Good Design Bad Design and DIY

Battle of the old NOS legend? Part 2

2012-01-05T09:22:00.000-08:00

After the new year woes over, now it's time to write again about our good old NOS DAC's. I have listened extensively to my NOS TDA1541 hardwired prototype, NOS AD1865 with 74HC04 and 74HC02 glue logic. Are there differences between them? Yes...quite so, even between the two AD1865, how so? It's just there and measurement proves that.

Last month in 2011 I just listened to 2 or 3 CD's, with 3 DAC in turns. For critical listening I listened to the following CD's :

Herbie Hancock , Possibilities. This is a cool jazz - kind of progressive jazz rock mix with famous singer on each track. There is a movie version as well. I listened tracks with Christina Aguilera here (yup..WOW...that Christina..), now you know why I like her..:). Also the Sister Moon with Sting here. Highly recommended if you bored with the usual mainstream jazz. Believe me, this is a very good CD both music content and sound quality, not to mention the swingin' , and some kick in the *ss quality..

The second CD is very old classical promo CD, by Teldec 1991, the title is Jonge Mensen op het Concert Podium. free translation : Young people in concert podium...and what a young people they were and are today !
I listened to tracks of the (then very young) celloist Matt Haimovitz on Max Bruch's Kol. Nidrei, op.47, and the barely (then) teenager violist Midori on Frederic Chopin, Nocturne, op. Posth. in cis.

See the Midori video here , too bad I can't find the exact video of Matt. Both player's were passionately deep in playing their instruments, that can be heard !, bristles of Matt's vest against the cello and his gasp for air were repeatedly heard. While the tiny Midori accompanied with piano and several noises and coughs from the audience really wonderful, and then that applause!.... You know these music can make you cry...so little fingers so beautiful music...

Here are the cheapo but very good sounding CD :

To me, the above tracks and Herbie's album and a few more are my "eargasm" ticket after a long hard day..

My system is as usual, Sony CDP950-digital out, Aikido tube pre-amp, Aleph J clone and the gentle giant ScanSpeaks Elan.

After some quick evaluation, the Vout AD1865 / 74HC02 is not very good, it's noisy and I'm not using any filter on the output (120uH and 0.01uF ?) so I changed analog out to SE JFET, sound better but the noise stays. AD1865 / 74HC04 sounds very good indeed, no noises but tiny bit lacking attack & speed compared with TDA1541 and AD1865 / HC02.

In term of speed, attack and timbre the verdict is TDA1541 followed by the noisy AD1865/HC02 and the calm AD1865/HC04.

On staging, details, separation : AD1865/HC04-gracefully wide, then TDA1541 and AD1865/HC02, maybe this is why most of DIY DAC pcb's with AD1865/HC02 always using SPDIF pulse trafo and output filtering.

On foot tapping and musical involvement, this is my get into the music quality and personally I rate this highly above details, staging and separation : TDA1541A, then AD1865/HC04 and last AD1865/HC02

By no means one or all the DAC were sounds bad, they are the legend!, only my power supply is right out mediocre :) told you that in Part 1, and these King DAC does not deserve it at all.

I did measure the contenders, here are they and with surprises ha ha..some predicted and some not :).

The Silence (of the lamb...he he..) : both channel measured

Woow...uugglyyy..!...this one is TDA1541A hardwired..a very far cry compared with Salas previously measured here, I'm surprised, strangely it's quite ok sounding, specially with frantic and very fast details on Herbie/Sting Sister Moon...already went to some haziness I admit.

This one is from AD1865/ 74HC02, best of the contender

This one is from AD1865/ 74HC04, notice bumps on 50 and 100Hz, that's the power supply...hmm, the only difference with HC02 is decoupling bypass, red wima mkp on HC04, and green Wima FKP on HC02, the lytics are Nichicon Muse KZ, 47uF. So get that green Wima's guys!..

Conclusion , this confirms my suspicion, AD1865 gives better performance with mediocre power supply, while TDA1541 ask a lot more to get in par.

The square 1kHz signal, I can't see any particulars, all DAC's are multibit's, very little pre and post ringing and fast!, maybe we can see the rise time difference ? from what I've listened AD1865/ HC04 is a tad slower than the rest, so the square flank should be less vertical.

TDA1541A

AD1865/74HC02

AD1865/74HC04

My favorite, 500Hz 0dB, now the results were predictable, especially that noise of AD1865/74HC02

yup..there it is again...uuuglly...:), TDA1541A with garbage...

And this one? AD1865/74HC02, not very pretty as well, you see (too) many spikes also small ones before and after main harmonics, that's where the noise come from, also note that the 50 and 100Hz bumps re appears! In my simulation the data stream, particularly on the left channel have a very short duration pulse before each left channel MSB, I'll update about this later. Maybe that explain the inherent noise.

The winner is.....AD1865/74HC04, in spite of my 'prediction' of single data line for both channel it doesn't reflected much here, and this with no SPDIF pulse trafo and output filtering

I'm now listening to Christina & Herbies A Song for You on TDA1541A..that vocal quality of TDA1541A is really hard to beat, but in my case here, AD1865-N-K with single logic gate 74HC04 is the clear winner!

Thanks for reading & have fun..

Battle of the old NOS legend? Part 1

2011-12-13T09:30:00.000-08:00

I don't want to miss writing in December :), there are some design things in the pipeline, but first my current DAC adventures. I have managed myself a piece of equally legendary AD1865-N-K DAC. It is one of 'a must have' DAC chip, I'm always a fan of multi-bit DAC, next in my list is the expensive PCM1704, may Allah The Great permits.

Me not buying ready made PCB for the AD1865 :), not challenging and not fun enough :), so the usual PCB layout-ing took some time, and to my surprise, this time designing is a breeze compared to TDA1541 board!. The AD pins are very layout friendly. I use both NOS schematic with 74HC04 hex inverter and the other with 74HC02 NOR, why?. Well, blessing in disguise really.

First I made CS8414 - 74HC04 - AD1865 pcb. After powering up the damn thing just gives noise, all effort to resolve failed, check and rechecking everything, tried other connections etc...very frustrating.

So then come the other schematic, now instead of 74HC04 I use 74HC02. I always think less is better. Using the 04 you use only 1 logic, while with 02 you use all 4 logic's.

The 04 however has 1 data line for both left and right channel, i.m.o. not so elegant, both AD1865 inputs are continuously bombarded with digital data, while in the OFF state, I can be wrong of course :). One way to try is to slit apart data trace with a cutter, and listen to your DAC, it still managed to get through!.

The 02 in contrary have 2 separate data lines for each channel. Mind you though, both NOS digital glue with 04 and 02 introduce data phase shifts between channels and clock (SCK from CS8414), with 02 comes worst. I know this from DIYaudio and by simulating the digital input-output data stream. But the shifts are small, and people says this is similar with moving your head 8mm during listening :), or is it?

This can be fun to check, because TDA1541A NOS with CS8414 data stream is exactly in phase! Ok, here are the plan, I use mediocre power supply (ex. Pioneer LD player), measure all 3 DAC boards : the original hardwired TDA1541A DAC, AD1865 with 74HC04 and AD1865 with 74HC02, all analog stage are my favorite single ended -DC coupled 2SK170 jfet, All board will use the same CS8414 receiver..how about that?..

How about the HC02 board?, still no luck bringing it alive!, must be the DAC...even a Vout mod from Iout did not help..

Frankly, I have listened to all of them :), I got my AD1865 replacement (many thanks Doc!....) , the AD1865-HC02 is still using Voltage output. This is preliminary listening though, I'll let them for a couple of weeks playing...

Here are the pics, AD1865 PCB's are CNC'ed, I tried as far as possible using same brand and same values component.

From bottom left : the 'Red' shoebox power supply, TDA1541A DAC, AD1865 with 74HC04 and SEJfet out, AD1865 with 74HC02 and Vout, note the coupling capacitors.

Now, back to listening he he he...

TDA1541A Balanced DAC, part 2

2011-11-04T11:14:00.000-07:00

I'm listening now to Andrea Bocelli's Amore album, right now Estate's is playing, using balanced TDA1541A-S1 DAC and it's direct heated triode output... the sound makes you really enjoying the Andrea's emotion... man... I have to write this instance..:). There were few moments like this when you're deep in to music you're listening, really caresses my ears and you forget about analyzing music, let alone measuring he he..I lost my measuring urge :). I'm just going to enjoy it before this DAC moving to it's new home.
Damned!!.....that voice of Christina Aguilera...what a talent!..what a waste in her pop music!...and just past midnight here, the volume knob barely at 9 ...Somos Novios......., my ears were tickled nicely here :)

It's have been almost 2 weeks since I have boxed up brother Y's balanced DAC and fired it up. Before that I use his DAC - Jfet - LME49720 opamp board and the little DHT bugger in my DAC box with the famous Salas shunt regulator.

I should mention that a few weeks back we have had a very nice blind test session. I for sure have participated, bringing this balanced DAC. The result? well a mixed bag really. I've heard 2 to 4 very beautiful sounded DAC there. A matter of taste though, only 1 of my favorite made it to final. The winner is a humble AD1955 DAC..congratulation ! here is the pic of my box with brother Y's boards.

There are the 4 Salas regs, at center the TDA1541A-S1, the DC coupled single ended Jfets, next to it is the balance-single ended opamp converter (with bit of gain) that going to ..yup, a pair of direct heated triode :). a very nice sounded ones those little buggers !, I did not believe my ears when listened to them the first time. I've made both anode & cathode follower/CF, the above is CF. Heater cathodes were battery powered. Why DHT output? I'm quite bored actually doing another 9 pin tube things, maybe octal tubes will be nice but I'm daunted with so many choices and what if the sound is not right...

Now in new box, not as large as mine, standard thin steel box, but modified with 8mm thick aluminium face plate and 2mm rear plate

Anti clockwise from top left : 2 EI trannies for digital supplies, 1st 2x Salas board, DAC board, 2nd 2x Salas , SE Jfet's, opamp with LM317-337regs for supply up to +/- 17VDC, DHT DC heater (modified Tom Ronan's supply), DHT board with supply, analog transformer (both high voltage, 2x 10V for heater and 18V for opamps). At center are cap banks for opamps.

This project to me is the most difficult and challenging, but worth the effort. This is my many "first-time" experiences with balance topology, first with I2S splitter, first balance- SE opamp, all including Salas board were custom designed and CNC'ed, and yes, first time DHT and I highly recommends you guys overcoming that famous DHT hum with DC heater!. very frustrating and yet rewarding ..completely gone? nope, but I remembered 'complaining' friend's DIY DHT amp..now I have experienced it coming with that "low' hum is admirable!.

Thanks for reading....thanks to brother Y for the challenge, may the emotion be with you!

now on : Solamente Una Vez (oh my...Stevie Wonder just great with Andrea..), Sony CDP950 digital out, TDA1541A-S1 balanced DAC-DHT tube out, Aikido pre amp, Aleph J clone tweak nr.xx, Scanspeak Elan

A new DIY audio adventure, TDA1541A Balanced DAC, Part 1

2011-09-26T10:43:00.000-07:00

With no design thing comes to my mind lately, why not sharing my on going venture into another TDA1541A DAC topology with you?. After finishing and more or less settled with my hardwired single TDA1541A DAC, a good friend have listened to it during a listening session at a friend place, he's blessed with a old pair match of TDA1541A S1 or what we called single crown. Pair match? yup that's right, each TDA1541 chip I've listened sounds different to each other, some subtle within one production batch, others like night and day :).

My friend 'brother Y' was impressed with the sound of his S1 chips sitting in my hardwired DAC and rightfully asked a balanced topology, I couldn't agree more. Balanced topology requires pair match of everything, from DAC chip down to Jfet and opamp output stage down to single resistor & capacitor in the signal line. After long study at DIYAudio.com (as always, thank you guys..) I've found the way how to do balance DAC using I2S splitter, yup, there is one good man behind this, Pedja Rogic, kudo's to you sir!.

The digital data from CD transport is first entering the receiver CS8414, which gives I2S data out, this data then go into splitter which feed 2 TDA1541A, one chip received Left data, the other Right data. Now the splitter does something else, it split the audio data into + data and inverts the other half of data into -data. So one dac chip will output L+ and L- analog out, the other R+ and R-, clever isn't?

From there I will have 2 pairs of (now) my favorite discrete 2SK170BL's single ended current to voltage converter I/V as in my hardwired DAC. From the JFET's the the L+/L- and R+/R- signal are fed to balance - single ended converter op amp :(...but this is the easiest & speediest way. After op amp you can do tube out, just what I did, later on that... :)

Meanwhile, I did got busy making that double sided PCB which since the start of layout I've incorporated possibility for paralel and balance configuration. Not a world class digital PCB I admit, but it works wonderful. I got also many valuable advices from the NOS TDA1541 man himself : Thorsten Loesch, thank you T.., and this means the layout is evolving :).

Well, quite an introduction to this challenging DIY project, now (finally) some pictures, I've made my PCB's using my (DIY) mini CNC machine that I've made back in 2004, told you that I'm a hardcore DIY guy :)

CNC ing is very nice if you do only limited quantity, and when you experimenting (read: playing :)) but take bit of time of tracing & converting ECAD data to usable GCode for machining, but what we get is nice clean process without chemicals and of course nice copper area for power and digital ground plane...

The long awaited parts were finally complete, specially the hard to find old Philip chip for I2S splitter, the famous Toshiba 2SK170-V for the 4 Salas regs, and the most important, a pair of dual matched 2SK170-BL, quad match were simply not available anymore. Got 1 quad match in my MC phono pre though he he..hope to share this as well soon.

Here is how the DAC and splitter board looks like

Top of pcb, the splitter with 3 red cerafines and the left channel DAC, bottom pcb are for the CS8414 and the right channel TDA1541A, notice detachable risers for ground return and power supplies.

And does these things worked? You bet!..perfectly by the way :)... here are early measurement using TDA1541 non A and John B's single ended Jfet, tested here the L+ and L- signals, the usual 500Hz/0dB

Green is the L+ signal, red the L-, they are exactly, well..within the limitation of our beloved VisualAnalyzer of course :), have you got one installed yet?
You see, the whole balanced thing comes to to this, you add 2 exact but opposite phase signal, summing will get rid of all even harmonics (what????...said a nice tube guy over there...:;D..), what left are the odd harmonics...and in total lower distortion figure.....why oh why???...said another tube guy....:(...

That yellow curve is full of even harmonic and it IS being removed. This cleaned signal then enters the op amp to be made single ended again, want to add flavour? you can, I'll add tube out just to add a pinch of 2nd harmonic. My brother Y will have options of DAC outputs to choose, SE JFET, Balanced JFET, SE opamp out, or .....SE Direct Heated Triode tube out

stay tuned & have fun

TDA1541A DAC, Part 2, " measurements "

2011-08-13T12:47:00.000-07:00

Now I have finished my DAC, also have done many tweaks (and still continuing...) It's time to do some "measurement", why the "...."? well because it is not very serious measurement, I have no mega hertz oscilloscope, no proper signal generator, but anyway there are plenty soundcard based software, and here is my favorite : Visual Analyser 2011, it is free and in my opinion, a must for DIY audio.

Why measuring ?, I think it is a proper step to at least measuring the frequency response of our DIY audio projects. We audiophile likes to have low distortion and flat freq response and how do you know that without measuring? no way, maybe possible with a very trained ears and a reference audio gears. Me for sure likes to see what happened with my music signal, starting by putting simple sinus, square and pink-noise signals.

How do we start? first we must have test signals, some test CD are available, and you can make your own if you're lazy like me ;), I have my signals made with Audacity, loop recorded with EAC then burned to CD. The Pro's among us must be laughing when they see the 16 bit/ 44.1kHz digital sinusoidal waves, at 10kHz the signals looks like a triangle wave, at 20kHz even worst :). So I limit the signal up to 1kHz, a proper sinusoidal and square form still very good recognizable. With this frequency we can at least compare distortion and harmonics of our DIY gears, no more and no less.

I have 3 gears to test, my new DAC, my old tubed Sony CDP950 player and battery powered bit stream Sony DiscMan. I had a 8xTDA1543 DAC at home, listened to it, too bad have not measure it. Here is the setup when measuring CDP950.

It is very important to have any software like Visual Analyser calibrated correctly or you'll get garbage results. Be careful with your measurement voltages, it can easily destroy your sound card. A simple voltage divider (variable resistor) or a full blown measurement jig like mine (SW Jig II) is a must. Measure the signal with your multimeter before connecting to soundcard.

What else? after calibration I measured the sound-card it self, I connected my laptop headphone out back to line input. I measure all signals including the 'silence' track to see the noise floor of my sound-card. Here are they, signal is my favorite 500Hz/0dB

the 'Silence' track :

500Hz/0dB :

I know, I should have set the X axis to Log scale..hey...I'm just a beginner remember? What do we see here? the noise floor is below -114dB, and the 500Hz gives quite a lot of low magnitude harmonic spikes that will come back when you measure other gears. Ok, now my old CDP950, silence track and 500Hz

Whoa...you see? that 500Hz thing looks way different than the sound card, notice the high (and nice sounded) even harmonics...well, it sounds muddier than my DAC alright, but veery nice..not enough for me now haha, I want transparent and nice sound here, so the CDP needs tweaking for sure. How about the noise? well, it is just below -108dB, no worries for this AC heated tubed out CDP. If I have log X axis you can see the 50Hz and 100Hz peaks there quite high. And now my new DAC with very low noise Salas shunt regulator (big thank Salas...)

Now the noise? way below my CDP950, maybe a lot cleaner than the sound-card, and noise floor bit above at -114dB. And the 500Hz is way cleaner than CDP950, bet this that gave me better transparency :).

And how the discman measure? This is interesting, TDA1541 on my CDP and DAC are both multibit non oversampling, while the discman has 1bit deltasigma and battery powered, here is the 500Hz, forgot to measure the silence here, but you can see here as well, close to sound card noise floor. So battery does very good job indeed.

And this Philips Bitstream DAC measure very well, very transparent, much less harmonic spikes and in reality sounds smooth but have less soul in the music.Attack and decay in the music seems constrained, high is relaxed but bit feels synthetic / canny..I still prefer my NOS multibit TDA1541 here ;). I did try to measure the interesting square 1kHz signal, but its for next time :), thanks for reading and get this wonderful Visual Analyser right away. (below 1kHz square on sound-card). Happy measuring...

Finally, my own TDA1541 DAC, part 1

2011-07-12T10:49:00.000-07:00

After months of reading and mostly 'arm chair DIY' (just sitting, browsing and thinking...) finally I came up with NOS (non oversampling) schematic that combines what available on the Net, adjusted and combined them to my best knowledge.

There are great guys out there sharing their thought on this 'ancient' but highly regarded chip, the TDA1541A. Let's see, these gentlemen are Thorsten Loesch, John (aka ECDesign) , Pedja Rogic, Lesha, Pavouk, etc. and one Japanese guy whose name I can't read. Thank you gentlemen. Please read here on where I've got a handful of these jewels.

After having a schematic next headaches were PCB layout, at least I made my self 'difficult' by trying to learn about digital PCB layout which is to my understanding different than analog one. There are so many do's and dont's here up from PCB track level to component soldering pads and I think that ground return paths were most challenging.

To cut the crap ;), I've decided to use perforated board, good, thru-hole one and believe it or not, it is a complete hardwired DAC. Why? just quick and dirty way to check pcb layout and whether 'my' schematic runs or ruined. So here it is, receiver chip is CS8414, power supply is (or was) from my busted Panasonic Super VHS player.

Output stage is single ended JFET (2SK170) as per John schematic, still using output capacitor here to block DC offset voltage. I did have to add LM337 voltage regulator for -15V. Put in my favorite 500Hz/0dB Denon test CD, a nice 0.74Vrms was read ..yihaaa...!. It's alive and kickin..., now tested with some music..with my SOHA and my Samsung earphone...wow, what a powerful kick and what a wonderful NOS sound..and then..that details, tons of them. I know, what I will tell you next is cliche, I heard details never heard before..

Well, enough with first impression, I know from experience, it can sound better. My new DAC already making my NOS, tubed out Sony CDP sounding behind a curtain. Audio DIYer like me are always know that your best sound today may not be anymore after hearing better one.

After some tweaking I decided to get rid of all the output capacitors, changed some parts with better ones, and I've settled with this Shoebox DAC for a week or two and tried paralleling 2 DAC on top of each other. I liked single DAC better though. Friends coming listening to it likes what they heard..I did too..removing the C out really makes a difference.

I still have a plan on power supply, a very good one that is : Salas shunt regulators. Here they are, I used 4 of them, 1 feeding the 5V of CS8414, 3 feeding the hungry TDA1541A. The Shoebox is replaced by MDF board :), the sound? even better transparency and immediateness..but it can and must be better yet again..sigh..I have to get wider staging..

Now I can sit back and relax, enjoying another tweaks on my Sony CDP, it needed too..:), my Aleph J clone also needs power capacitor change..until then. I must thank many friends here, prof ATP for regulator boards, pak Richard for his generosity with his 2SK170-BL's, Mr. Bowo for his IRF's and more, last but not least to Mr. Doctor for the DAC chips and of course my DIY audio friends. Thanks for reading.

in the Audio pipeline :
'measuring' DAC, Sony CDP950 NOS/Tubed and Sony Discman..

Washing Machine and Mosquito Hitter

2011-06-17T10:51:00.000-07:00

I'm feeling like writing today :) but not yet about DIY audio though he he. Recently my wife complaining about our washing machine, the centrifuge just don't work. This machine is less than 1 year old. Here it is.

Opening the front cover reveals this, hmm...another plastic failure case..man....just hire me to do your design :), or pay me to check your design and products...

The broken thing is safety switch housed in plastic casing. When the lid is open the centrifuge stops. Consequently when this switch is broken you can not turn on the centrifuge, since it is a 'normally closed' switch. What went wrong? well, the switch housing is kind of poorly designed, small footprint of attachment and cross sectional area, with lots small and sharp notch. Perfect recipes for failures waiting to happen.

Here is another details of the switch housing. Blue marker indicates cracks that originated from sharp notch.

I reckon only about 2mm X 15 mm square of area that must withstand cantilevered housing of 60mm long. If the force required to close the hard copper leaf switch is 0.1kg then the root suffers 0.1kg X 60mm of bending load plus 0.1kg vertical load reaction, small loadings? maybe..but that small loads repeated over 200 times and with that sharp notch? exactly!...for quick fix I just hardwired & isolates the leads...at least the centrifuge works now, without the usual 'safety' feature though :)..

Another product I've observed is the famous mosquito hitter. We have used and throw away many of them, they're cheap and short lived :). The green one here last a month. Most annoying is that the switch of the lamp is on the wrong side, so when you put it on that side, you will unintentionally switch the lamp on, emptying the battery...yes the mosquito's is laughing at me :)...

Now we got another one, sturdier, better looking and ergonomics, very powerful, until I got that high voltage - low current power right on my leg..I screamed the **** off...yes the mosquito's are laughing even more louder ...sigh...ze power never the same again..absorbed by my leg I think :)

So in one evening with nothing to do, I opened both hitters..1350VDC mylar capacitor?..no wonder :)..

and 2 A3 rechargeable battery...now I know how NOT to buy another hitters...:)...watch out you mosquito's...!!

CD Jewel Case, CD "perfect sound forever" vs good old Vinyl

2011-04-10T09:44:00.000-07:00

I guess when it come to audio format I'm one of the lucky ones. During my childhood I have listen to old but very good sounding tube radios and mono's black vinyl in 78 and 45 rpm. Later on my dad bought a Lenco turntable and bunch of 33rpm black discs, Paul Mauriat, Frank Sinatra, Demis Rousos, Nana Mouskouri that I still remembered, oh yes and Koes Plus :).

Then comes the bulky Philips Compact Cassete and the final compact cassete. Yea, one of my cousin prefer Teac tapes reel while I played with cassetes and vinyl. . My kids and many younger generations knows only MP3's, Ipods and for sure never heard of Walkman and Discman either.

It is now about 30 years after CD introduction. There were Laser Disc, Beta, VHS, S-VHS, DVD's in between. SACD, blueray, MP3, AAC, Flac, and bunch of other 'transferable' digital formats. Me? I prefer to hit my brake soon. It's CD, Vinyl and one of those 'bit to bit perfect' digital format out there.

When the silver disc first came out I remembered one of the marketing hypes - "perfect sound forever", after 30 years let us see what happened to my old -early CD collection and of course similar aged vinyl ones.

But allow me to whine for a while :), the jewel case of CD's. For me it is irritating. The hinge breaks off very easy, it happened just after every time you buy new one. This is a bad design case for me and sure for others and after very long time no one cares. They even selling empty cases :). What is going on?

Hinge of the case is the most heavily loaded section. Although the case is made of though polycarbonate (and later, cheaper polystyrene) there is one problem here, stress concentration. Because of the geometry around the hinge the stress there is much higher than in other area. The location is at the root of the hinge. There is a sharp corner and to make things even worse, people add ridges there, further weakening already flimsy thing.
The stress there is at least 3 times higher so no polycarbonate and polystyrene is tough enough. First cracks will develop and then.....

Actually it can be prevented by adding a stress relieving geometry, such as adding a round in the corner. Mysteriously this never happened, maybe it's good to have many broken jewel cases for the producer

Luckily in recent times there are several better CD packaging in the market, but I think this new packaging is what I called 'cost driven' designed. Just because world oil price is hiking- so virgin plastic pellets are more expensive, particularly the transparent ones that the music producer need to show off the cover. Here are some of them. I loved the paper ones. Never breaks , have a nice booklet that do not need to take out and put back again :) and makes little noise when it falling down...

So there is my whining and now what happen with the perfect sound forever ? I have here one of the GRP CD, Chick Corea Electric Band (1986). I did nothing wrong except playing it occasionally and most of the years just sitting in the box. Some years back I started to saw holes through the disk, and the holes are getting bigger and more holes appears...so much for a perfect sound forever.

Another CD, Chick Corea ' Light Years' (1987) album stays fine, just as fine as the vinyl one below. I guess it depend how lucky you are with your CD's. I have many more CD's damaged by it self than vinyl damaged by my worn needle. I do have some scratched and warped vinyl. But the vinyl do not change it condition during all that years!. At most finger prints gets moulded and fungi growing in it and after washing the disk it plays perfect as it gets. I do have some pristine old CD as well after storing it more that 20 years.

So, does CD gives perfect sound forever? No, I don't think so, Vinyl is? no it's not either but it's closer ;)). Thanks for reading

in the pipeline :
my 'new' TDA1541A NOS DAC, single, parallel, reviewed together with on board DAC and 8x NOS TDA1543 DAC

Entry to wonderful world of tube audio

2011-01-30T01:53:00.000-08:00

When we first think about this 'ancient' amplifying device, at least 2 things comes into beginners mind, lethal high voltages and expensive tubes. Both of them drives many first time DIYer away. I must admit it's not easy for most of us to start with glowing tubes after the comfort of making a Gainclone or chip amp.

Well there is an answer in this, a cheap tube and low voltage supply or what we call as B+. To add some warmth in clinical sound produced by CD player and our gainclone, a topology called buffer is all we needed. Buffer does not amplify, it's just make driving your amp easier by providing better impedance matching, also the gain of this buffer is actually less than 1.

About a year ago Mr. Arif from Tubelover introduces tube buffered Gainclone, he gave us the schematic during DIY audio Blind Test gathering at Mr. Didik W. home. There are high voltage tubes that can sound very nice in low voltage, such as 6DJ8, 12AU7, and the Russian 6N1P. This 6N1P is the cheapest and widely available so I started to think about this buffer when friends at Solfegio Forum are looking for cheap and 'safe' tube gear. So here are the story.

Schematic from Mr. Arif (many thanks for sharing pak !) it is his hand writing :)

My translation of the schematic and board layout

But before I built the buffer I would like to see how it's perform by simulating it, I want to know what is the 'harmonic distortion' figure say at 1kHz sinusoidal input signal. Fisrt the input-output figure,

Traces : green is input signal 2Vpeak -peak (just like most CD-DVD player output), yellow is the buffer output, note that it's not 2Vpp anymore. Now let's see the harmonics of the same signals,

Green is the input signal, yellow is the buffer output. Clearly the tube does something to the original signal, it's adding harmonic peaks at 2kHz (even harmonic), 3kHz (odd), 4kHz (even) , 5Khz (odd) and 6kHz (even).

What does this means, it's means that we get distortion on the output. Notice the higher 2nd harmonic at 2kHz relative to the other, people says that this is the 'nice' sounded even order distortion, just like what happen in nature, so we tend to call it pleasant sounding. The not so pleasant sound are the odd harmonics.

So simulation show quite promising figures. Will the simulation results reflected to real build? I don't know so let's build this buffer and fast forward to the final one after days of tweaking :)

My buffer is using 6N1P tube, 6.3VAC heater, why tweaking? after initial listening using a DVD player it's really needed that, the buffer sounded mediocre but it have potentials. First the output capacitor, final value is 6.6uF, then power supply electrolytic, also the type and brand of the drop resistor for heater (from 12VAC) has significant influence to sound.

I did tweaking after hearing and 'measuring' the DVD with and without buffer. I've found a nice software called AudioDiffMaker , its do the comparison of reference signal against a 'tweaked' signal. In this case I compared direct DVD out to Buffer out. I did 2 signals, a 500Hz 0dB sinusoidal from my Denon test CD, and music signal. Here are the screen shots.

AudioDiffMaker form

500Hz direct DVD out

500Hz Buffer out

500Hz Difference DVD-Buffer

Here we see again the harmonics of 500Hz signal, what to understand? first check out 2 small peaks after large 500Hz peak. Direct from DVD shows 2 small peaks upwards, out of buffer 2 small peaks one upward (even 2nd harmonic) and the next downward (odd 'bad' harmonic), so at least the tube somehow alters the peaks. As for the rest the AudioDiffMaker sort out the difference and in term of signal it is very large difference and you can hear it!.

I did another signal, this time a real music signal. here are the differences, and yes you can hear them as well

the form

the difference, both channel

So finally Bill Waslo, the developer of AudioDiffMaker gave us the tool to check whether you have 'improved' your system using new cable or 'voodoo' tweaks :). As for me, the software will not tell you how good the sound is and I have tweaked my buffer to a level that I missed something when I'm not using it :) some day I'll measure it again with AudioDiffMaker.

Check here for details & friends building their first tube buffer. Thanks Bill, thanks pak Arif. And to my friends..built it, tweak it and enjoy it

Cheers

DIY Audio pot pourri 2 : Woody film capacitor

2010-11-22T09:04:00.000-08:00

Long time ago I came across a Dutch web site explaining electrolyte capacitor modification. Recently a fellow (senior) DIYer Mr. Paul also have done similar mod with paper in oil capacitor, DHT Rob reports improvements on replacing aluminum can with wood filled with beeswax. Also mixed results from Pak Paul from what I've heard.

A longtime DIYer friend said that you'll get sound improvement just by lightly sanding the caps. Nothing but subjective result analysis though, but I've found a freeware just for that, detecting difference of the same music signals one as a reference- the other may be through a different cable - more about this in my next post.

I've got 4 Solen MKP capacitors belong to a friend ( Hi pak Johny..) so I'll give a shot. I've made mahogany tubes, soft wood cover. I've broken in the caps before for very long time on the bench. So here are they. The tools are small PCB drill for the caps leads through the soft wood cover and a tweezer. This soft wood is press fitted to the mahogany tube.

I still have some space left in the tube, so the Solens are wrapped with the tissue and pressed in to the tube. The input and output leads are marked, they do make sound difference how you connect them even the Solens are non polar.

Wrap like this, plenty of excess on both ends, they can be removed easily.

Excess tissue paper removed with tweezer

There you go!. A pair of Woody Solen :). Notice that the leads are not centered. Good idea if you marked them before drilling

I did a comparison in my Sony CDP -M75 - looks awesome!. There are difference in sound - not much but the Woody tend to sounds smoother. Definitely better than the original CDP ouput (with Elna Duorex 2 electrolytes).

Here my friend Aphinx using the Woody for input coupling on his D class amp. Originally his input coupling was the Russian MBM 1uF we found the woody sounds better. Below the Woody tested against Ampohm MKP, he likes the Ampohm better .

So there are differences in sounds when you do this kind of modification, whether the sound is better or worst is another matter. Any explanation on this phenomenon? Let me guess, first the skin effect - greatly influenced by surrounding material or dielectric- nowadays 'we' prefer natural materials - hence the the sanding, beeswax, natural fibre like wood, cotton, silk and paper. Silk? I think one electrolyte maker used it on Elna Silmic...

Secondly vibration - with tight clamping the caps are protected from it. Lynn Olson told stories about 'microphony' effect of vibrated capacitor - it wasn't pretty picture - he said . I believe them because I've heard the mod my self. My Spica TC-50 crossover is placed outboard , guess what? the caps vibrates like crazy there. So, at the very least we should tie, damped and fixed our caps very well. Good luck !

DIY Audio pot pourri 1 : Spica TC50 crossover tweak

2010-11-01T09:37:00.000-07:00

During several months I've carried out many small audio tweaks. Not full blown projects though but I think it's maybe quite interesting sharing them :).

First is my Spica crossover tweak, continuing effort IMO still necessary to replace those old ECI lytics. This time I like to tackle the high frequency section. On September 2002 the Spica designer John Bau was interviewed by Enjoy the Music.com and asked what to do to improve his Spica, one of his answer is to change all the electrolytic caps to Film.

So here are the pics, some caps, made some 'risers' for easy soldering and quick caps change.

first on the board are Wima MKC 4.7uF, Green Nichicon Muse's 10+22uF, Black Nichicon BP-S 4.7uF. Left them for 3 days about 12 hours on play, sound? me not like :). So instead of waiting for another 3 days I just pick - place - listen - change. An advantage of working with broken - in and old caps...

The Wima MKC can stay, it sounds well for coupling capacitor on my CDP-M75, so next on the board is 0.1uF K42y Paper in oil bypassed the BP-S, still not liked it, then I went to my garage pick some big 22uF Solen MKP - the last pair I have, this in parallel with poor small 10uF green Nichicon Muse, sit and listen...man!..the bass is like I never heard out of this Spica..I wonder though..I'm working here in the high freq region and I get that bass?..well the Solen and the Wima stays!.

Now the job is much easier, that what I've thought and I was wrong. I got better bass & high, same and maybe better staging, but some tracks still give sibilance. Swapping the BP-S to Evox MMK did not help, same with 'old' Yellow Rubycon.

The last 4.7uF film cap I have is a pair of el-cheapo yellow Audiophiler..yuck.., nonetheless I've soldered them and ...its sounds ok, no, they sounds quite well indeed..and totally acceptable to me, much better than the Evox.. So the Audiophiler stays! After 2 months listening I tend to let this setup freezed and change the 10uF Muse to MKP and maybe another Wima MKC replacing the Audiophiler, I miss the high notes timbre of acoustic piano sometime.

My lessons here, tweaking the sound for Mid is very difficult, many times proven cheap parts perform well in combination with other. Thanks again for reading guys..

In the pipeline :

-Part 2 : film cap gets woody jacket..

-Tubelover 6N1P tube buffer in depth..

Electric Fan, MMC holder

2010-10-08T10:37:00.000-07:00

Now, some design cases recently I've observed as always - at home. A memory card holder and an electric fan. Nowadays you can barely escape from plastics, everything we use almost certain contains plastics - one form or another. Let us begin with another well executed design first.

A plastic holder made from PP of polypropylene. Very nice, compact and functional. This one comes with my digital camera. It's function is to hold a pair of memory cards, MMC. Lets try to see how such a design took place.

First is surely the design requirements to function. It needs to hold MMC's, must be transparent or a bit see through so that we can see what cards inside, light, very cheap, not easily breaks, the card must be secure enough - not falling down by itself, easy to use etc. These are just wordings, no design concept or design sketching whatsoever.

Now comes the Task. Task comes after function. Tasks are whatever you need in the design in order your design to function properly, still no real design yet at this stage :).

To cut the story short, take one of the design requirement, lets say " easy to use", now let see the 'design' below. What features coming from the 'task' of the holder supporting this requirement?.

There are several, as this 'easy to use' requirement is the most vague and hard to implement. We can see small recesses on both side of the holder. Curved recesses on the sides are for your, say left hand thumb and middle finger. Also on the top where you can pull the card inside using your thumb and index finger...smart eh..?. Last thing you want is to be able to insert a card and can not pull it out....

What else? yup, easy to use often means easy fabrication as well. Hence the two parts, mate both half, press clicks..you're done. Why not one part? well it can but the metal mold will not run very long. Lots of small thin 'cores'. Easy to break with high molten plastic pressure and you production will be ruined.
See small slit and a bulb on the right sides? It is an integrated spring, it task is to push the card to the left wall. This creates enough friction, preventing the card from falling down..another smart design.

Such a simple thing like this are full of hidden smarties, which greatly contributed by systematic thinking in terms of Function and Task. Most of innovations are made by thinking hard this way, rather than 'eureka' thing..., smart!.

Now, a saying that says A Chain is as Strong as the Weakest Link is really well said. Look at this beautiful small electric fan. Same brand as my problem rice cooker. Their products have the bad habit of early broken up..sigh..watch out!.

All the parts, plenty of them laboriously made. The styling is not bad either. The fan cost less that $15, last less than 5 month just because of ..weakest link!. see below.

The weakest link in this case is the transformer wire. It gets hot, even there is thermal protector- the wires are broken somewhere in the winding. So all the labor, effort and resources just wasted. Really? not much though.

Buying this fan keeps the factory workers get their salaries. The seller get profit and can take care of their family. What about I'm throwing this fan in garbage bin then?
Hmmm..there comes the most environmentally friendly job in the world...the Recycling Man!. Yes they live from our garbage, they will sort and pick all the plastics and metals for further recycling. They get money paid for that. To me, the Recycling Man is my Super Man!.

What do you get? Next time you buy new product please don't be surprised. 80% of that product was indeed once your garbage :))
And what did I get? just a lousy transformer bobbin with 30ish gauge enameled copper wire from which I planned to make something like this see below and several hours of Audiophile-foolishness fun :). Thanks to broken fan and Bud Purvine and his DIYAudio postings on ground side electrons..what ever that means..

This is the first time I can relates design stuff with DIY audio thing. Thanks for reading my foolishness.

TDA1541A , more than I can handle!

2010-09-18T10:35:00.000-07:00

Actually I've planned to write about yet another good design bad design thing, this in waiting my mood to finish-tweaking my Spica TC50.
During visit to my audio part supplier friend just before a long Eid el Fitr holiday, I in all a sudden being blessed by a chance of trying out a bunch of the legendary TDA1541A DAC chips from Philips, not one or three pieces, but 4 tubes with about 8 to 13 chips each!. plus a pair of TDA1541 (non "A")..More than I can handle..so I've postponed the Spica tweak and design thing...

My friend is just one out of many victims around the world of TDA1541A frenzy that still on going even today!. It's the Fake or Genuine TDA1541A debacle that started out around 2004. This chip is so high in demand that some people just make fake ones and sells them. Just read this thread about it in DIYAudio.com. My friend have tested the chip randomly some 6 years earlier, none working he said..

Being a TDA1541 fanatic (see my Sony CDP950 tweak stories starting here ) I took the challenge of testing all 4 tubes, may be, just maybe I can get one or two working chip. As a positive thinking guy I assume there is always some good thing out of even bad guy!. I even told my friend if I can find a good chip I will let him know. So here is the chips, my story & the pics..enjoy!

The tubes, yes in the 90's and early 2000's Philips made the chips in Taiwan, many says even with better production process than in Eindhoven Holland. The highest grade, the TDA1541A/S2 (so called 'double crown') is made in Taiwan.

Testing all the chips here in my salvaged Non Oversampled Sony CDP-M75 with Sennheiser PX100 headphone. This player was totally wrecked and non functional. I've got it from a good friend (thanks mas Yuda!). I planned to take out the DAC only for spare and piggy bagged to DAC in my Lampized Sony CDP950 for higher current output. It turned out that I have the luck to bring it to life :) so here we go..

After testing the chip halfway? Guess what?.. there are 5 chips or so that completely working! But beware!, and I know from the DIYAudio thread later on, there are some chip that can blow your CDP!. Here are the 'test result 'modes' :

the CDP just doesn't want to turn on, no display at all when powered up - the chip felt cold and is busted
as above but the chip felt warm- busted as well
the CDP and the display turns on, the disk spins and ...HEY..it worked!....yippee!
the CDP turns on, the display also, the disk spins, chip is very hot and I can hear some music-heavily distorted and interrupted often..then I heard loud DC signal through my daughter's PX100..frantically switching off the player.......what... was.... THAT??..

Tried to turn on the player no luck...sigh...yep..sometime you gains..and other time you just loose..within a fraction of a second! This 'mode 4' is by far very dangerous. What I did was repeatedly switching the player on and off during this mode 4, a big No-No, learned later.

After checking the M75 for supply voltages on DAC pins, I found that pin 15 reads -34VDC..woow..it should be -14.9 or so... Luckily the other day I got schematic from Mr. Jeffry, thanks Pak!..read them, testing some components & yes one transistor is surely went busted.

Late in the evening and no electronic shop open for sure, I just browsed my old PCB's junk collection, looking for equivalent replacement, yup, found a better equivalent, 2SB734 in place of the fried 2SA1015. Fit the B734..aah..yes..the player worked again, so I continue testing, until my left hand thumb felt numb putting and removing those 28 legged little monsters...this time I'm very careful, no more switching in on and off again. No display- no disk spin -the chip is simply busted, and yes I recalled another 3 or so chips with 'mode 4'..

At the end of this tense testing session I can smile, BIG TIME :)...the TDA1541 non A worked very well, and hmmm let just say ~20% out of 50 TDA1541A chips are working too. My positive thinking and all the effort paid off well...the harvest? here are they..:)

My conclusions are that these chips were : original and working well (mode 3), the original damaged-rejected ones (mode 4) , original totally damaged rejected ones (mode 2) and the rest is just plain fakes (mode 1)

Me and my friend strokes a win-win deal. I think I'm getting closer to my dream, a dedicated DAC......so much about these and our audiophiles earthly needs...sigh..., thanks for reading my friend..

Rejuvenating Spica TC50

2010-08-22T03:48:00.000-07:00

I'm currently listening to my Spica and also waiting for my fastening break time, why not continue the Spica story?. This legend is known for its 'disappearing' and staging quality. When you listen to it soon you'll forgot that there are speakers in front of you. Just sounds floating around and in front of you. That's the way I liked it just like my more refined Magnepan SMGa.

My Spica : pre 1988 built !

One box sounds not so loud as the other. So I starts measuring both with my DIY Speaker Workshop Jig II, here is the result, yes the "B' channel just sounds softer.

Now it's confirmed I planned to move the internal crossover to outside the box for better tweaking and checking. I opened both boxes & smells 22 years old odors of this spica. All drivers were in unbelievable good condition, original French Audax including hand markings for each driver to match the crossover. Not to forget, thick genuine sheep wool blankets

So lets see the crossover, as said in the forums, electrolyte capacitors , those yellow things says ECI on the marking. Hell of electrolytes, after more than 20 years !. Inductors are cheap ones with ferrite cores both for high & low frequencies. Resistors are good metal oxyde though.

One elco is not in good condition, white thing comes out so must be leaking then. Here is my old story about electrolytes in loud speaker. Not bad, one out of 10 elco after 20 years!. I just replaced it temporarily with cheap MKP until I have the mood for tweaking.

Leaking capacitor

Now it's the turn of the enclosures - a closed box with no leaks. I have to make sure of no leaks all the time.
I reversed the bolt and nuts for crossover PCB to be mounted out the box on the rear side. Notice white glue and rubber washer..no leakage.

Hmm..does not look pretty yet. I'll put the board in a box when all is tweaked right..that's a promise for an old friend. How its measures now? well quite ok I think, both box sounds more balanced now.

Here is the crossover as per today :) waiting for better components, some are almost ready and still in 'burning' process. Nichicon Muses and BP, recycled Philipes- Epcos- Wima MKC , some green and silverish Russian paper in oil and maybe a pair of 30uF big oil can?..who knows.

As for now I felt little to be modified, its sounds already good enough for me, groans-moans and throat sounds of Diana Krall's voice is just awesome also her piano 'kick'. Maybe I need to remove a little harshness and sibilance a bit for complex music. That's the next tweaks are for. Thanks for visiting.

There are second chances in my simple life : Spica TC50 speaker

2010-08-19T11:57:00.000-07:00

Have you ever thought that you'd have to make choices in the past, well a luxury choices that is. And all a sudden there you are, after say more than 10 good years being confronted again with the second chance right in front of you, dejavu all over again :).

Mine happened long time ago when I was still a near graduation student in the Netherlands. I started looking for a pair of serious loudspeaker to take home and live with it..just like a wife isn't ? except it comes in pair :).

At that time I was considering an unusual speaker, Magnepan SMGa and another pair which I have listened at my well funded friend apartment, Spica TC50 driven by high-endish gears such as Goldmund turn table with Van den Hul Grasshopper cartridge, Aitos tube MC Pre-pre and Aitos tube power. Really an experience not to forget to hear the sound.

Finally I married to the Maggie SMGa, took her back to my country home after graduation. Why SMGa? they are more expensive than the Spica, more than 3 times. The reason was that Maggie in combination with my system at that time, second hands Counterpoint tube pre & hybrid power amp sounds quite good, maybe scoring a decent 6 points out of 10 points of my friends gears.

Fast forward to present time, I started doing DIY audio thing and with several 'hardcore' audio friends planned a visit to a place known as electronic ghetto in Jakarta, a Bronx kind of place with many unexpected audio jewels if you're lucky.

And how lucky was I indeed. In one of the shop I saw a familiar sight...a TC50 Spica..to be honest I'm bit disappointed to see both grills full of holes and one of them are totally broken into 3 pieces. Hmm..lets see the speaker driver then..looks unfamiliar though, especially the woofer, not the same as my friends. Need to gather more info on the net after asking the price, quite pricey for jewel from the past. Got home and started browsing.

Here is a link on the net. Yup exactly, the Spica's have stood bravely the cruel tests of the time. With many fanatics. A proof that the TC50 is a legendary loudspeaker. Woofers and tweeters are no longer in production, the designer John Bau just don't want to continue his creation, etc. etc...

To cut the story short, the next day I went back and got myself one of my 'youth' mistakes home to correct, a pair of legendary TC50-Spica, here is the pic. the date was 12th April 2009, just maybe after 10 years, nope, more than 18 years later, can you believe it?

Talk about second chance? I will give this Spica a real second chance..it needed too.., one speaker sounds not as loud as the other, the grill have to be made anew..hmmm..sounds yummy for a tweaker like me..so the story will continue for sure..thanks for reading

DIY resistor for DAC current to voltage conversion

2010-07-08T09:58:00.000-07:00

June this year is my zero writing month. Don't want to skip July so here it is another DIY audio adventure.

My tweak darling, the Sony CDP950 is almost weekly being changed. I used it for learning both digital & analogue wise. At DIYAudio I came across a strange resistor made by John a.k.a EC Design. It is quite complex to be made- although fully doable in my workshop. Here is my 'dream' Ri/v - the resistor that convert current out of the DAC to voltage that goes to the tube grids. In my case its valued 33ohm.

A beauty isn't? (hopes John wouldn't mind I use his pic.). Why all the troubles? well this DIY resistor promises low capacitance - non inductance - and high wattage. All good for tiny current out DAC.

What I can not get are a coated resistance wires & patience for winding it. Being a naughty DIYer like me, I have once hammered several of those white bricks, just to see what's inside :). It turned out that for low R value the R is wire wound. Higher value some kind of carbon film. Hmm..this brings me to an idea..

So, armed only with double tapes and 2 pairs of white bricks 39R/5W here we go :

The tools are 1 hammer, 2 pliers, cello-tape, double tapes (thick & thin semi transparent), scissor or a cutter, a tweezer.teflon tape...thats it.

Take care not to break the wire from the end cap. Tape the wire to the cap & legs for strength

Thick double tape both end stripped & glued to the table and start making zig-zag pattern of the first wire lay up about half of total wire length (my case 28cm ~ 1ft). plan for the double tape length.

Cover the first lay up with thin double tape, next lay up

The first lay up is now 'insulated'. Start now with a second layer, now you know why I need a semi transparent tape :).

Measurement shows a lower R value than the original 39ohm. This happen once you unwind the wire from the ceramic center piece. Not to worry & its closer to my 30ohm target :).

Cut both ends, add another thin double tape, peel wax paper on both sides & start rolling

Two DIY Resistors :)

Rolling & teflon taping. measurement shows quite acceptable 'tolerance'. After rolling the tapes the R value goes higher a bit.

In action :)

The sound? well the 'cocoon' beats my Philips metal film for sure, and about a 'tie' with the pink Takman's, not yet decided though ;). Highs of this DIY Ri/v are quite breath taking...

But...hold your horses, recent discussions on DIYAudio with EC reveals that this DIY Ri/v is not completely non inductance yet. But it can be made non inductance, using a so called Ayrton-Perry_winding and for this I need to insulate the wires using a proper lacquer. Not so hard to do compared with 5m long EC's wire :).

So ..my adventure is to be continued...thanks John..

Don' buy just a faucet - buy a heavy one!

2010-05-18T09:57:00.000-07:00

Did you ever change any of your water faucets at home? How often and how many already?. Well I'm kind of lost my count here, and add another count last long weekend..sigh...

There..the bad faucet number XX..totally new, bought in a well known hypermarket (c4), a well known brand (k**m****r), hyperlight, hypershiny and last but not least, hyperItaly as shown. This thing cost about 1.5USD, comes complete with thick lovely blue hanging plastic tag and a teflon tape, nice bonus..o is it?.

The usual routine: closed the central water tap, removing the old bad faucet number XX-1, happily wrap the teflon tape (my favorite thing to do) laa..di dam..di dam..put and turn the number XX to the wall socket, there goes the wrench..laa di dam...la..di..WHACK..what the...? Is this faucet that bad? It's just can not took even the light twist of my light wrench..whaaa...!!.

Did I need to comment on the design - material - fabrication? No..not a bit. Even the fluorescent colored plastic faucet is doing better than this hyperItaly. This is an outright robbery...where is the Ombudsman here? Hellooo?..knock knock!.

Do me a favor. Just buy a heavy real brass nickel chrome plated faucet. It will cost you 10 times more but will safe you 10 years of not using those red plumbing wrench...while I left here with very expensive teflon tape...thanks for reading..

Good, and not so good design, Plastic Clip & Microphone Jack

2010-04-09T10:30:00.000-07:00

I've thought that after posting mainly DIY audio stuff, its time again to look at design things. First, a 'sorry' microfone jack for my son's electric guitar and second a deceptively simple clip.

I've bought these poor jacks to replace low quality cable that comes with the guitar. Just rush to nearest small electronic shop around the corner & found very low quality jack, asked for another but to no avail :(, My son just want to play (read: make noises..) so I grabbed a pair knowing I can fix them temporarily.

So whats wrong with these sorry jacks? See pic below, the paired one. Built is very poor, thin and flimsy solder prongs, cable grip that's too short to fully clamp my light brown Canare mic cable.

But the biggest problem is that the ground shank (negative) does not stay fixed to the threaded body, in fact you can easily turn the shank relative to the body. Now that's a good design or what ?. I can imagine my son will make more noises - pops and cracks all the time due to poor ground contacts...

The temporary fix?, I've soldered the prong to the body - so that's solved. The Canare's sounds cleaner and more full bodied against noisy giveaway cable :)..

Since I know this is a temp-fix, I bought another pair, a much better build and sturdier thicker metals and you can not turns any of the shanks. The clamp just can grip the cable nicely with slight overlap. Just a week ago or so the sorry jacks gave up, so 10 minutes jobs with this new jacks and my son can make more noises...sigh..

What I don't understand is why on earth you make things so badly? You'll do badly on the market, you've spent at least the same amount of money and effort to produce them and what a waste of resources? Think about the shiny metal plating process that pollutes river?. Beats me..that's why we need industrial standards, in our case SNI-short for Standar Nasional Indonesia

Now to the good executed design..a simple plastic clip shown below. What are they used for? It's used originally for bread plastic wrapping, yes to tighten the 'bag'. I always hate the green tapes - while they are a breeze to apply for the store clerk but not to us the user.

Now somebody very smart have made both the store clerk and us happier. this clip is very easy to apply and to detach. All plastic design philosophies are used..in short, one piece, integrate all functions in one single part.

Lets see, there is a hinge, a toothed ribs for better grip, there is a lock that function very well, easy to lock, not easy to open unintentionally but easy to unlock ..now..this locking things sound familiar to me? an echo of my past..yes it is one of the design requirement for an aircraft door - even after crashing !...how about that!.. for a simple plastic clip?

None of any car doors in the world even come close to this clip! Now don't get me started on public transport doors in Indonesia ha ha....(this one is unique..you can throw garbage and yourself in and out the door while driving....)

And the best part of this 'simple' clip is...see for yourself....:), my 4 thumbs up for the clip designer

iPod Mini alive again!

2010-03-14T19:26:00.000-07:00

Last year sometime in November we got lightning strike at home, just when my daughter sat in front of her (and our family) PC..She told me blue light appears accross the main board. The PC is dead, so does the cable modem, the printer and my daughters iPod Nano..sigh..but thank God she is OK.

The Nano got so hot she put it in the freezer!.I wasn't at home. Alas it was over then with it. So with no budget after buying new motherboard-second hand-Phenom X4-cable modem, her dead iPod mini is my target operation. Thought that only the battery needs replacement.

Spend a half afternoon to read how to open the thing-and finally have luck to change the battery after admiring the Wolfson DAC-Phillips chips-no wonder people like the sound of this 1st gen mini. Apple just wants only the best for their products that time. But the display shows discouraging message..a frowning face appears then followed by an URL..bah..., must be the mini drive that gives up..so did I..throw a towel.

But with luck and persistence of a DIYer-I found this link..of the late Mark Hoekstra, who back then in 2007 have already done it!..replacing the venerable minidrive with 4GB compact flash memory card. A couple month later and it's just yesterday I found a 4GB Transcend CF card that known to be working well with iPod. I've spent a couple of hours and yes..it works, here are the pics. Veel dank Mark..you've leave us wonderful knowledge..

The mini drive-new batt-and CF card

This thing makes the old iPod mini to a cult status..(Wolfson 8711 DAC) and yes there are people out there tweaking this little guy !

after restoring with iTunes....

With backlit ON & the busted Nano..Apple proprietary chip in there and a korean memory chip..:(

This morning I've made my daughter happy, also my son who got new iPod shuffle for his birthday to day..not to mention my wife who otherwise will spent more money!..So, please throw away then your iPod 1st gen...to me :).

Sony CDP950 hardware mod-wooden transport

2010-03-08T07:35:00.000-08:00

After modding this Sony CDP950 heavily, these are the results.
Electronic wise, well never ending tweak that is :). Found during a recent blind test with a poor result ha ha..It turns out that the R value for current to voltage is very important, and you need really second-third even fifth opinion to judge the sound when you're constantly modding and didn't know anymore of 'correct' sound. So it was my take for another lesson.

Hardware wise I consider it finished..yihaaa!. Acrylic plates does wonder and also a quite difficult task in taking care of the old transport. It's all wood now :)..not the famous Phillips VAM or something like that , I dubbed it Sony WAM :), short for Wood Augmented Mechanism..just kidding :). here is the tranny cover

The 'new' Sony CDP950 'Lampized'..thanks again for your mail Mr. Fikus..
A broken beam of my workshop roof, or a part of it :) & a design drawing
Made some noises..
Fitting & mating plastic, wood & the CD player..

Adding a nice old teak top layer
underside of the 'WAM'..
Nice gold plated springs..(guess where the h**** I've got it..)
Fits well..
fastened & adding brackets..
Well..more pictures this time. As February was a really busy times. Also recently this CDP yet again showing another sickness. The CD just turns very fast counter clock wise. After cannibalizing my 'spare' Pioneer LD player for few chips, particularly the spindle motor driver chip. this old guy just runs well again. Now back to that never ending tweak again...thanks.

Sony CDP950 TDA 1541 NOS ed and Tubed

2010-01-15T23:44:00.000-08:00

I have to confess. I'm really excited with my Sony CDP950 with 20years old TDA1541 DAC. Several tweaks & heavy modifications resulting upgrades in sound each and every time. I always set my mind towards the final tweak-a tubed CD player- since last year and starting to spare my money for collecting tubes, HV transformer and other component. And of course continuing learning how tubes works.

Last tweaks were the opamp change, the bypass operation here and the non-oversampling things.

At the end of last year I've heard that a Blind Test for CDP and/or DAC going to be held in January 2010, so it's time to put the effort. Top cover is cut for tube base plate and top loading system. Also 2 left over 8mm thick acrylic plates for beauty and tube protection were made with my own hand :).

Schematic is as always..from Mr. Lampizator himself, a SRPP with 2x 6N2P-EV, for this I thanks Pak Dino. I plan to use hybrid tube rectifier - AC heaters all the way and 6X4 tube-USA origin I got as a gift from Pak Ado. HV tranny, sockets and resistors were from Pak Alex. Thanks to these good people! I can keep the mods at low cost, in term of materials that is :).

Socket, components & wiring were planned, sketched & routed. Keeping with my Reuse-Reduce habit, wiring and, diodes and the capacitors are all used ones.

The simple plan is you tap the Iout signal from the TDA1541, route them to the 6N2P grids. There is a 60-100R from grid to ground which convert the current to voltage. Here is the I out wire, doesn't have to come out of PCB bottom this time :)

Piggy bagging the HV tranny..

Refinished top covers & tube base
Now the messy, tiring & fun parts...no..not that fun anyway..
I blew my cheap compo speakers-I think the tweeter just gave up-they got 75VDC for a second or so..sigh...stupid me. Also I've got 255VAC on my right hand fingers..boy..felt the jolt up to my arm pit..the hairs there felt smoother now :). How about the sound?...there is music..very low level..even I have cranked up the volume..lots and loud hum, check and recheck everything..no result, de solder & resolder the R's..also not helping. changed the AC heaters to DC with 7812 regulator..even worst..I gave up, just pull out the tubes- de solder the 220VAC from HV tranny and get ready for the next day Blind Test just with Non Oversampling tweak.

I have said the NOS tweak is a leapfrog compare to Bypass tweak. The blind test result confirmed this..at least the for Jury, session 3 got number 3 out of 5 players. This old CDP-loses to would be winner-CDP333esd nosed-reclocked-BGed and external tube buffered CD960..interestingly 4 out of 5 players using TDA1541 !. The non Jury said other way..last position for my old CDP..so..I have to make my CDP really sings or else...

In order to understand what is going on, I've made a simulation in orcad, yes there is 6N2P Spice model out there. Simulating the SRPP with Iout of 1kHz at 0.4mA (TDA1541 datasheet) shows nice high Vout :0... So what might happen? Searching the Lampizator site for (hidden) clue..no result--Mr Fikusz hiding something? nhaaa!... My tubed CDP very low Iout-Vout signal indicates that the Iout from DAC is being corrupted a great deal, like everything here in Indonesia :).

I can only point that the BB OPA2134 as the I corruptor !. Gothca...the opamp pair on temporary detention now. Turn on the CDP next the HV switch...yes..a big YES...Ingram Washington sings loud and clear!..almost no hint of hum..this AC heater tubes!..

Ingram Washington sings :"...What the difference a day make...." this day for me was 1 week after the blind test. The OPA2134 now permanently out of my CDP..too bad though as I can not directly comparing NOS-OPA2134 and SRPP. Or is it necessary?..No it is not necessary.

The difference is very clear right away. I will spare my comments for later :)..my wife just shortly said.."empuk"..means (maybe) "smooth" in English..that with up to now unbearable to hear CD from David Foster & Friends..

Wiring & sound testing this way :) with Gainclone amp and 2 samsung small speakers.
Bunch of resistors to try. And finally testing in my system..with a C out coupling rig for finding the right caps. I'm tired but fully satisfied. There are some minor tweaks must be done on the HV PSU, R values & types, Cout and last but not least the CD transport itself..maybe a Phillips CDpro2 transport Clone..:). Thanks for reading my DIY audio adventure.

Rice Cooker, Good ones?

2010-01-15T09:53:00.000-08:00

Last year I have started this blog with a design case. Inline with 'tradition' here we go again. This time you may ask, what the h*** is that stone doing on top of my rice cooker?. Are we (God forbid) so poor that we eat stone?. No..please no..

The answer is here, no stone-the cooker cover won't close, I eat no rice, so does my wife & kids, o yeah..the cats as well :), what has happened?

I've seen too many cases of plastic products used in the wrong way. Plastic and heat do not go together see here . The same goes here. The blue hook is intended for locking the cooker cover to the lower part. After few months, yup, it just lost the grip and hence come the stone. I have once broken a plate full of rice because of my slippery hand :(.

Maybe, just maybe, the designer have calculated the hook well, but the maker just want to have cut the cost by using recycled plastic. Or its just another bad design..gosh..

My wife has learned, she bought a new cooker..no..not the same brand..ever!, see here the good solution? Yes..a steel hook, you can go very very far with steel in 110 centigrade..lets just hope it will not corrode too fast, as the hook is galvanized..bravo C*****S

LM3886 Gainclone, My Fisrt DIY Amp

2009-12-29T10:44:00.000-08:00

Exactly this month last year in 2008 was my first step into DIY Audio. Full of doubt I've started with the popular LM3886 chipamp a.k.a. Gainclone which gained enormous popularity among do it your selfer around the globe. Never good in electronics, don't understand a thing, but out of love for my daughter I've tried it anyway. So first I made 2 'bird nests' and I'm surprised with the sound. I have decided since then never to buy branded amp anymore, make them yourself. Its cheaper, educating, fun with many friends and most importantly much better price to quality ratio.

2 proper casings was designed & crafted in our workshop, for power supply and the amp itself. Here is the 2 PCB's and a solid aluminium heatsink.

A 'see-through' amp casing, to date contains different and better components.

The pairs behind and front.

Wonders happen when you love your family and friends..long live DIY audio.

MP3 USB-MMC Reader

2009-11-23T16:48:00.000-08:00

This is my recent DIY audio thing. I found this USD 7,- little handy MP3 player that fits me and my family needs. My car audio head unit, a Sony cdxGT700d has lost its CD mechanism for quite a while, so no CD or MP3 anymore.

I'm also tired of using my old Sony discman as source in car. Sounds quite ok though, after some blue- tack tweak, but I have to put it on my lap when driving or the player just sputter, cough and more when I hit road bumps. Here is the 'replacement', a simple cheap USB-MMC reader, feed with 5VDC. Add a 5Volt regulator such as 7805 off you go.

There is an Aux in, it can only reads MP3's put on the root directory of your MMC/USB. Read the file in sequence only, no shuffle thing, its ok for me and many motorcycles rider who use it. At the beginning of each track the volume increased to full level in a second or so and gradually soften when track skipped, one at a time. It also memorized the last track it plays after shutdown.

For my kids, there is another version, bit more expensive but still below USD10 :). Provided with a remote control, FM tuner, display, EQ function, maybe shuffle thing as well...

Some tweaks are needed after listening familiar MP3 ed tracks. Four very small electrolyte caps, 10V, 100uF replaced by good Elna Cerafine, 16V, 100uF I have on hand. Boom...the sound goes to higher level!. Add blue tacks on top of the chip, the crystal and the sounds settles in orderly manner. Definitely it sounds better than my brother stock Simbadda MP3 player.
I have learned though, that how you rip the CD is very important for the sound quality. My first test rip is using Cowon Jet-audio. The result is quite OK, but after comparing with the original CD you missed quite a lot, especially in staging. Even I have ripped in dual stereo. Then a friend told me about EAC, Exact Audio Copy. I have read it in 6moons some month back..I'll try this for sure..

After a few days of use, I decided to give this cute player a cute casing, a beautiful solid teak one!, finished just with..teak oil...hmmm..

Analogue Volt Meter, Revived

2009-11-20T08:21:00.000-08:00

Sometime, we in our workshop just throw away damaged things into a drawer. The same goes with this cheap Heles AVM, after a few use it's just don't swing anymore, goes into one drawer some years back. When I bought old capacitors recently, I need to see needle swing on the meter, Digital Volt Meter is no swinger :). So, in line with my principle 'use whatever you have' , old Heles is my operation target.

The problem turns to be a loose copper wiper and wobbly shaft of the disk. Thewiper was just fastened by 2 plastic pins that was melted by a solder to clamp the wiper down. Well, this is a good plastic design practice for non moving part, for moving part you need larger pins or a long rib.

So here are the fix, add a screws to the shaft and wiper. Now the needle swings !.

But the fix brings new problem..as always, a solution creates new problems :(. There is no room for the screws, so a 30 minutes fix became 1.5 hours... Bottom of the casing is drilled, then cut a jelly cup bottom (remember..use whatever on hand..), epoxy-ed them..voila!..

Another problem, the meter just does not want to stay put , so add 4 rubber pads, cut from black foam I have in my garage-double tapes them..

finito..and still fit in the old box ..., mother earth and my wallet is saved again, just 2 things I have to throw away..the casing cut out and a jelly cup with no bottom..now lets swing!

Sony CDP950 Tweak Part 3 : NOSed

2009-10-11T11:49:00.000-07:00

After enjoying my last tweak on CDP950, its time to see 'What NOS is means to me'. I've got info from The Lampizator site a while ago and made a plan on real PCB, here it is on bottom side.

This operation needs careful surveying of actual pins on the PCB. The job is really bypassing the digital filter chip CXD1088 who does the oversampling. The 1088 got its inputs from CXD1125 then outputs to TDA1541. NOSing is going direct from CXD1125 to TDA1541 with the help of shifter 74HC164, more details please check Mr. Lukasz Fikus site.

The first step is lifting the jumpers and resistors on the far side (from the 1125 & 1541), I use solder suction to do that. Then the 74HC164 soldered and glued to PCB, I've bent flat all its pins for easy soldering, see below.

Second step is to insert the wires (UTP) into pin holes of lifted jumper-resistor to the top side of the PCB & soldering them

Woow..looks easy, but I've made one mistake, it has cost me my brother in law amp..hiks.. :(. No sounds at all came out from the RCA, then I tried to short the R's...yep, some music (Andrea Bocelli-Amore CD) then silence...the amp is dead. Then I checked the plan, yes a mistake. Wire from 1125's pins 76 and 78 is the other way around, the wrong one it is, shown on the last two pictures.

Fixed them and YES...I heard Andrea singing through my throw away cheapo earphone..I knew the sound is already very good even with this horrible earbuds.

How is NOSed CDP950 sounds?..well, I think I'm closer now to my goal. It is a leapfrog from my last tweak, here are my early personal review :)

My systems : source CDP950, PreAmp Aikido DIY-6CG7-6DJ8 tubes, Power Amp DIY Aleph J clone, Speaker Magnepan SMGa.

Ze Sound : Wide and Grand, all the details & ambiance, effortless, not one bit tiring at all, you can follow each instrument easily. Timbres are really more correct. I'm not listening to lows, highs and mids anymore everything are there.

Surprises, compared to second tweak :
Some fast beat & complex tracks I usually have skipped due to unbearable & tiring sound now just opened up, no more congestion--newest CD from Dianne Reeves, Renee Olstead are full of them, hey its not the recording! Its YOUR CD Player!..

I hear many clicks and ticks and garbles during track change, pause and stop. I think I will live with them, or I have to look for muting schematic later on :)

Conclusion :
Don't blame your Pre Amp, Power and Loudspeaker just yet. It turns out that they are more capable than I've ever thought of, given the best possible source, that is, my CDP950-NOS..(..soon to be tubed ha ha hah...)

Now I urged everyone I know to NOS their old TDA1541 CD Player. Last but not least, really BIG thanks to Mr. Lukasz...

Really Good Designs

2009-09-13T08:40:00.000-07:00

Here are two good designs in the house. Used them frequently as good example for my students. First, my daughter's first iPod, now no longer functioning and needs battery change, and an ice tray.

Where are the good design aspect on this nice iPod, beside the styling & functionalities?. Well, they're the little grey spot at the center of the holder and the holder itself. Why?. The grey spot is made of silicone rubber. Without it the iPod just drop-off the holder to the floor...bang!..

Why again?. One of the reason people using rubber is because of they increases friction, things dont slip easily, think of your car tyres , underneath your desk foot or under yours!. Other function is fluid-gas tight sealing, that bring us to birth control or health issue, but its completely off topic here :).

Now it's the holder turn, it has to be engineered correctly to push the iPod against this rubber spot. Not to firm so its too difficult to put in the iPod, and also not to weak so the iPod stays put in it.

How does it works?. The friction works if we put a force perpendicular to the friction surface. So we know now why the holder has 'wings', they're there to generate clamping force against the grey spot.

This design aspect requires deep tought in ideas, design, engineering and manufacturing. Only a talented designer will came with this. Oh yes, I can imagine how the 'American' engineers going very tough and uncompromising against Chinese Manufacturer on plastic materials and holder dimensions ;). My hat's off to the designers!.

The humble ice tray.

The second example is my 10 years old 'Korean Made' refrigerator Ice Tray. The trays repels ice cubes by twisting the tray handle, so a shearing deformation occurs between the ice and the smooth plastic wall container..then the cubes fall.

Very clever, just what we have to do to get ice cubes out back in the 80's. Take the tray out, put under running water and bangs and twist the tray :) to get the ice.. in short, making some noises.

Also heavy engineering must be involved here, and prototyping for sure to check whether the design works. Plastic material used must be of high quality..there must be no too critical area on the stressed tray...here are some numbers.

10 years x 365 days x 2x twists = 7.300 times and still going (I bet the manufacturer aims for at least 100.000 twist action..). Now add same amount of stresses in the container, because water expands little bit when frozen, also add temperature change from 25deg C to 0 deg C repeatedly. Whew!..that's a lot to be considered. Even the collector tray below has cracked its bottom, the test of time is unforgiving. That's what it takes for a good design, reliable functioning.

Sony CDP950 Tweak Part 2

2009-07-24T09:15:00.001-07:00

Now I'm not feeling very well today, and just rest at home, let continue with my CDP950 tweak story. After changing the standard opamp to OPA2134, now is the turn for heavier tweak operation. My reference is a site called Lampizator run by Mr. Lukasz Fikus, I respect this Polish guy works. He is a no BS's just do it yourselfer type. It took me about 1 month on-off to study his stuff & my actual Sony PCB. Some work to reach 'little' audio nirvana eh?.

The operation is to bypass the TDA1541 DAC output from the first OpAmp (OPA2134 is now permanent), from first opamp output a wire is soldered to a set of coupling capacitor then to extra set of RCA plug. Sounds simple, but when you look at the PCB?..confusion is assured :-). Things getting better when I got a CDP950 schematic explaining connections in the DAC-Audio ouput area. Why this operations? the old CDP950 will sounds much better!, less parts & damage to the signals,..so Mr. Fikusz said. And after more than 1 year doing DIY Audio & hearing friends CDP hard for me not to agree. Now is my turn to hear the tweak my self.

step 1 , identifiying pins on PCB (opamp output & ground)

step 2, soldering wire to first opamp output

step 3, soldering ouput capacitor (phillips MKC 2.2uF) , RCA plug & ground. I like to keep the original fixed RCA for comparison

step 4, Now I can test the new sound!, and ? ...wooww..all I can say is that I could not believe that I have spent >17 years listening on this garbage CDP. I never liked the CD sound anyway, that is why I never upgrade to new CD player. Liked the old vinyl best. Now this almost trashed garbage player is my tweak darling.

I'm not just stop here, I know the sound can always be better and there are another steps to CD audio nirvana : making this 4 fold oversampling DAC to a non-oversampling or NOS DAC, then add a pair of tube buffer..long way..
But first just experimenting with coupling caps, better wiring, and variable output also bypassed. Coupling caps of the DAC also a tweak target using salvaged mylar caps from thrashed Blaupunkt Bremen car set. Another ways of reusing parts & save mother earth. Below, trying the sound of Russian Paper in Oil 2.2uF K75y-24 (the green thing).

above : harvesting result & Blaupunkt PCB, the mylar caps are 100nF, just the right value!

Final selection of coupling caps, I settled with paralleled yellow Phillips MKC 2.2uF, Blue metalic EroFoli 0.22uF, Back to back unknown electrolite 47uF (guess them Epcos?), in total of ~26 uF. These caps, especially after adding the electrolite, sounds very open-transparent , balanced low-mid-high. Overall the new sounds are very sweet, fluidic & analogue, now my Thorens TD320MK2-BlackPearl MM Cartridge-Cambridge Audio Azur Pre-MM have to fight very hard I must say.

final selection

Other tweaks are changing the diode rectifier to a ultra fast ones (BYV27), changing the old motorized pot to the sweet sounding little 50k ALPS green, replacing PSU Caps of DAC to Elna Cerafine, also a mishap of my tweak frenzy..a lesson learnt on my account. Changing DAC coupling caps the original 100nF ceramic cap//100nF mylar to Wima// mylar & a pair of (Auri?) MKT at the MSB pins. Theoretically the sound must improve since the Wima's and the MKT are better parts, the resulting sounds are worst. Details are lost, far from airy..well, once you get the correct sound, you must restrain yourself, except if you've got 14pcs of Black Gate NX of course!. Off with the wima's!, luckily I still able retain the sound I liked, just clean the solder pads thoroughly with acetone. I heard scary stories that you may not be able to go back to 'original' sound.

Diode, ALPS & tweak mishap

I'm completely astonished by the sound, and it's not even using 'better' op-amp than OPA2134, not NOSed yet & no Tubes. Thank you to all my DIY friends & cheers to Mr. Lukasz Fikus. Do not believe me, just try it yourself!.

Sony CDP950 Tweak

2009-07-16T07:51:00.000-07:00

After a friend recommends a bypass operation on my CDP and reading a site called Lampizator, I decided to do just that. The CDP output is bypassed from DAC-first Opamp, to coupling cap then to RCA output. But first, before executing this heavy surgery, I just change the cheapo JRC NE5532 opamp with audio grade Burr Brown OPA2134. Steps are quite easy, removing the opamps, resolder a good pair of IC socket, install the OPA2134..thats about it & enjoy..

How does now the CDP sounds?, quite surprising, it just sounds like a more expensive player such as Nakamichi CDP1 which I have heard for several days at home, vocals are warmer with touch of 'air'-singer's vibrato are now more pronounced, overall my CDP sounds less harsh & more enjoyable for long listening sessions..hmm, couldn't wait for next tweak.

power point, good design until it's broken

2009-06-07T07:51:00.000-07:00

Before I plan to continue my tweak story on my old Sony CD Player, lets us see this power point problems.

Like other people, I like to plug in those power cables to one hub. But beware of the rating. No more than 1PC and 1 LCD monitor, plus bunch of wall wart adapters. I bought this one some 4 years ago, no problems until now. I have selected this one from bunch of others.

Things I've looked from what was visible underneath the packaging :

wire thickness or gauge, the thicker the better
available ground connection (3 prongs connection), safety reason
thickness of brass receptacle & ground contactor in the socket, for durability & contact firmness
plastic housing quality, choose heavy one that easy to clean & does not change color

Conclusion: this power point is a good one!, good designed & made, it lasted 4 years

Just a couple days ago, the red lamp switch just gave up. It made a sparkling noise. That was no good for my daughter's PC and LCD monitor. In fact, the LCD went in to protection mode. No picture at all. One of the mains pin is melted..so I have to cut the cable & hiks...throw away the plug..sorry mother earth..

When I tried to replace the switch, it turned out that the manufacturer used special screws, that need a special tool to unscrew them. Well...screw the maker!..they just want us to throw away the thing & buy new one..no thank you..not me!..safe the planet you know?..

Here is what I do to open the case & replace the fragile switch (no lamp this time). Lamp gave heat, heat is the enemy of plastic..they went broken because of long time heat exposure.

I just cut the screw head with mini grinder wheel, along with plastic casing , just deep enough to create a thin groove for unscrewing, but still retain the screw bosses on the casing. The rest is history. This power point will go for another 4 years and I feel good saving it for the trash!

How about the design?.. Its good up to the switch durability. On the end product life cycle? such as design for servicing & for environment protection? I'll give the maker zero out of 10 for making us throw away things and buy another.

Sony CD Player Laser/ Optic change

2009-04-09T10:04:00.000-07:00

Finally I have replaced the old optics of my very old Sony CDP950 CD Player. That is after many weeks of frustration due to weakened laser optic (type KSS150A). Many hours I've spent to adjust the small trim pot (just below the lens assembly, on the back side), tracking & reading is getting worse every time. Hmm, it time though to look for new optic. Asked around some shops..there are no KSS150A everywhere.

the kss150A

No wonder, this little guy is older than my daughter!!, bought around 1988, one of the second generation of CD Player. In one shop one guy advising me to use a newer type, the kss210, he is a honest man, told me that some player can be replaced some not..price? less than USD 4. What the heck, I'll try that along with a new disc motor with long shaft (mine is wobbly), availability is very good here. Old motor is made in Taiwan, the new one is Malaysian made.

old disc motor

Got home and soon the Sony is in pieces.., removing the motor you'll need to desolder the board. I've marked the + and the - of the motor. Next is removing the old optic assy & install the new guy. Whew..that was easy!. The new motor is also installed as marked in the PCB.

bottom view of tray

See the green board? That's the motor PCB. The right side motor is the tray motor, the middle one is the disc spinner. Just below is the optic, the one with wires and red connector. Here is the top view.
Also the variable output capacitors are replaced, see below.

Now comes another lengthy frustration, ...got everything re connected, turn the power on, put a CD..well it's spun very well..but, where is the music?..no reading?..no time on display?. Well..its might be not as easy as I've thought, I remember the shop owner words.

I noticed that the CDP main board has many trim pots, wonder what they do?. Before I tried to trim the pots I marked them. So I know their original positions. First the trim pot on the optic..no luck. Then the rest of the pots on the mainboard. Yes, they have some thing to do with the optic head & motor speed (the servo things!), still no luck..at 3 AM I thought I'll have to say good bye to my CDP950.., pity though, they have many quality components. Nichicon Muse & Elna Duorex electrolytic capacitors, nice resistors & ceramic capacitors, there are also high quality silver mica ones. And most important..the now sought after TDA1541 DAC/ digital analogue converter.

I thought I'll go to sleep then. The next morning I need to listen to some music (I'm still felt frustrated all right), I picked up a DVD player below our TV set, hooked & put a CD and..blah!!..the sound is very harsh, tiring to hear... I thought that some tweaks will tame this USD 20 player...I really missed my CDP950..

Again, the cheapo DVD is in pieces, changed the capacitors on the power supply board, they've used a switching one, with very small transformer. One capacitor near the trafo is bulbing on the top side, waiting to burst open..who to blame? Ok. everything is re installed, put a CD and hooked back to my system without top cover. Hmm..the CD sound's stabilized now..but WAIT!!..why is the disc turns the other way as my CDP950?, this DVD turns the disc clockwise viewed from front side...could it be?..that my CDP?..or this DVD is wrong..or?

I rushed back to the Sony, desolder the motor, marking is ok, + on PCB is + on the motor (red dot)..ok, now resoldered the other way around, + on PCB is - on motor, put all things back..MAGIC!!....my CDP reads the disc flawlessly, tracking is excellent, track changing is lightning fast..so..this is my tweaking DIY audio story..really full of surprises. Next, this CDP will get custom top loading!. The tray system is not working well. But for now..welcome back my old fellow!!

Bad, Bad Hammer, Bad..

2009-02-20T09:23:00.000-08:00

I thought this post should be about DIY audio..until a couple days ago I found a smallish (broken) hammer. This hammer was new, bought by a friend because we do not have a small one.

Well this post is going to a BAD Design Case again, or to be exact..bad material selection, bad manufacturing process..bad quality control (doesn't seem it has any)..God know what else..

Ok, here is it..

I'm kind of speechless when I saw this pretty hammer. The material used is bright cast iron instead of a forged one which is a standard in the (good) hammer industry. Also the head is broken right at the most critical area and happen to be less material there. Have you seen a (good designed) hammer bulged around the hole of handle attachment?..Exactly! Here, some more pics.

The label says "Target" Contractor Grade ..Graphite..whoaa!!, what contractor? house of cards for sure ha ha.., another look how the attachment hole looks like, far from smooth, just waiting for a small crack to emerge (this material is kind of brittle) and then...thwak..broken

The only good design here is the color selection, it's pretty & catchy, makes my friend bought it, ..also the wooden handle is stronger than steel ha ha...too bad I didn't saw his expression when it happen. I'm still speechless..do you?

Check your Loudspeaker Crossover

2009-01-29T08:15:00.000-08:00

It was last week, when I brought my 'analogue arsenal' to my Dad's home. He want to listen to old vinyls he discovered lately in the house. All set up, all LP's cleaned (washed to be exact), put an LP from Tony Bennett..this great guy voice's sounds great..but why is the right speaker sound more pronounced?..aah..the old Technics left tweeter did not work..why?..

Took the box home and off the grill, ups..the woofer dust cap did not look right, off then with the tweeter, the mid (it is a 3 ways system) and the crossover. Checked the tweeter with a multimeter, yup..it's dead all right. Those cheapo crossover !, they use a very cheap bipolar electrolytic capacitor (small cylindrical thing). They have a limited life, and when it did went bad even the speaker protector can not do anything. There goes the culprit, and I have replaced it with two quality film capacitors, now you'll have extra 10-15 years of listening pleasures.

So, please check your 'expensive' JBL's, Bose's, Sony's, Phillipses, etc. If you see this kind of capacitor, replace them immediately with film type, the same value of uF and same or higher Voltage of course. Do this before your tweeter goes in to smoke, and if you planned to go the DIY way make sure the warranty time is out.

When I took off many parts of the speaker (it's an old Japan design), I have noticed that I have to use 2 types of screw drivers, found many types of screws, each different in size and form..what??..

In term of mechanical design, this is a BAD design practice. Too many parts, too many items, one too many tool, way to many part bins during assembly, storage, purchasing-inventory management..on and on..(you get the drift..).

I have counted 6 types, plus another 2 on the crossover assembly, oh yeah, another one on the speaker protection PCB in total : 9 types of screws. This is too expensive. Is Technics still around this day?

Thanks for reading

Pentium Motherboard Case

2009-01-14T08:36:00.000-08:00

Okay..this one is about PC Motherboard. I have one just like this one on the left at home.

What is wrong with this one? Well, not much will go wrong in, say 2 years. Ok. let's see. The white fins is the heatsink of the CPU, on the right is the DRAM, the brown connector is an AGP graphic card slot.

Note the layout of the CPU heatsink, also the golden one..the direction of air blows through the fins is down towards the AGP slot and up to upper side of the casing, vertically blowing thus. This is important. The heat is better transferred this way (chimney most of the time it is vertical isn't it?).

On the other hand, my third PC, the CPU heatsink has a different layout, the fins are oriented horizontally..that is..the hot air blows directly to the DRAM.
For those who have already tried to touch the DRAM..it is hot already by itself, never mind the additional CPU 'warmth'.
And to make things worst..add some dust..(lot of it after 3-6 months in my case)..and they stick to the DRAM chips, making them more difficult to get rid of the heat, and yes..the DRAM and the slot are also turning brown in color.
Within 3 month I have to replace 1 DRAM, one slot completely shorted & shows burn marks..me? I know better now, which board to choose.

The What's, the Why's and the When's of this blog

2009-01-03T10:49:00.000-08:00

Hi friends!

I like to introduce myself here, I'm an aerospace engineer living in Indonesia (a MSc. if you want to know).

The What's :
This blog is all about my passions : design engineering and DIY (do it yourself) - at the moment especially in Audio (yes..I'm an audiophile, a design-geek and of course an avid DIY'er )

The Why's :

First-in design & engineering.

During the course of my education, my first-second-and finally the third employment in local aerospace & automotive industry I have gained a kind of sense of critical design evaluation.

Until to date, as an independent design-engineering consultant, have designed-built & prototyped many products, machinery, custom equipment, big and small, very light to 700tonnes, in the air, on the land and sea, underground..I have always use that sense.

And you know what? I've started to evaluate things that I and my family member uses everyday..a broken toy, tools that keep falling when you put them on table..there must be something wrong. And the answer is yes. There are many products that are poorly designed and manufactured. But there are also things that makes me smile..the good designed products. So there you go "...Good and Bad Design..". You'll find here examples of both..soon.. :-)

Secondly, in DIY- do it yourself

I don't know why (this is not the Norah Jones song.. ) since I was a kid, I like to create things my self. Smashed tin car in pieces & look inside it, modified my first bike-with front telescopic and rear suspension at 12, my go-kart in grade 8, and on..and on..until today.

Why DIY?. It comes out handy & you will know better at the end. I have saved my money most of the time by fixing many non functional things we owned (yes, you'll see them soon). In current tight financial situation, DIY is the way to go.

Why pay someone for the job you can do yourself?, why buy a Denon amplifier costing USD400,- when you can build from kit for less than USD50,- that sounded like an USD2.000,- amp?..well you know now. But very careful, DIY can be expensive..it is in time you spent & money that is. In audio for example, if you search for perfection..before you know, you'll spent USD150 for a pair of capacitor.., don't worry there are much cheaper ways...again..there go my DIY.

The When's :

Why just now I write this? Yesterday I tried to organize my DIY files & photo's..OMG!..there are more that 10 folders of individual "projects"..it's about time to share them with you...hope you'll enjoy & learned (from my humbly mistakes)..

It's in my third years (soon fourth) that I gave lecture on Design at one of local university, also I have documented many products, good & bad designed, thought this might help many people including students. You know, it might even help you when you buy any products..look close, compare, try..imagine..whats will going wrong if you are using them... Me? I don't want spent my hard earned money for things that will regret me sooner than later..so, now is the time. (My God..there are even a broken things they sell next to competitor product!.)