Selasa, 12 Juli 2011

Finally, my own TDA1541 DAC, part 1

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, 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..