Kamis, 29 Januari 2009

Check your Loudspeaker Crossover

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

Rabu, 14 Januari 2009

Pentium Motherboard Case

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.

Sabtu, 03 Januari 2009

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

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!.)