merry Christmas. I need help!!!!!!

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Dear all,

Today I received sample from japan's friend & he advise me use this type of resisters used in my Version II TDA1541a Non-oversampling DAC. He said this precision rersisters was very good in digital circuit. My Version I 1541a kit was used Dale in the digital circuit. My friend said he can offer a good price to me for the 5/1000 tor & 25ppm model.

pls click the website.

http://www.koaproducts.com/english/index_02.htm

model which I prepare used in my DAC Version II.

http://www.koaproducts.com/pdf/090-091-MFP.pdf

http://www.koaproducts.com/pdf/088-089-MF.pdf

The brown one in the photo was 5/1000 tor, blue one is 1/100 tor.

I hadn't any experience for this resisters.

pls advise

thx

thomas
 

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dear janneman ,

do U had any experience using this brand resisters??
Do U know the performance about this brand resisters??

my previous kit use dale metal film resisters, all 1% tor & 50~100PPM. But this brand was 5/1000 tor & 25PPM.
Better Spec than dale but performance?????? I don't know, so I ask diyers to help me. Hope can get some advise!

Japan suggest the I/V use carbon film & digital circuit use this type rersisters.


thx

thomas
 
AX tech editor
Joined 2002
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Well, you must understand that I am a typical sceptic about "this resistor sounds best" or "this cap should have the plastic jacket removed to sound best".

There are so many components in a typical equipment that I find it very hard to believe that changing a few to other types will be audible (exceptions below). As can be read on various places on this board, there are many, many factors determining the perceived audio quality of a piece of equipment *other* than the sound itself. To mention a few: size, color, weight, price paid, your friends opinion, your expectations, etc.

On the case of resistors, unless you have a special piece of equipment, 2% tol should suffice. Every competently designed amplifier should be able to function according to spec with small variations in components. For example, transistor gain often varies over more than a factor of two. There are some exceptions: sometimes you need a specific ratio in a design to set a current gain or something. In such cases you may need two resistors with a certain ratio, and it is easiest just to get two .1% ones. But other than that, the tol (within reason) has no bearing on sound quality.

Resistors DO vary in noise between types. Again, the designer should take care that the amp doesn't need some unreasonable low noise resistors. Still, in input- and feedback resistors, for example, especially when higher that say 5k or so, low noise types *may* lower the measurable and ausible (ear-in-speaker) noise. Finally, resistors should be reasonably stable, for instance not change more than say 1% over 50 degrees temp change, which I think comes out to 200ppm/degree or something.

In analog stages, the resistor noise for example can directly turn up in the analog signal. I have no idea how this could ever happen in digital circuits. Digital circuits are known for the lack of resistors. I don't know to which digital circuits your friend refers to.

So, my answer would be: no, I have no experience with these specific resistors. But.... see above.

Jan Didden
 
Dear janneman & pburke,

thanks for your opinions & share experience to me.

BTW, How about the precision series of philips.


http://www.texascomponents.com/Tx2352a.pdf

This type of resistors will be very good in the I/V resistors of the DAC. Per DAC only use 2 pcs, I think will acceptable for them although in high price.

but, dear Pburke, do U compare the performance for

http://www.texascomponents.com/Tx2352a.pdf, vishay & caddock????

thx

thomas
 
Hi Thomas

KOAs are Ok. Many of them are made in China now so I think you can easily find cheap sources for them.

For I/V, I prefer to use things as neutral as possible. Caddock TF02 is the one I use on your kit. Vishay S102K, the bared one is another good choice. They both sound the same to me. I went for the Caddock simply because it was cheaper! :) Riken's sound has a distinct signature, I use RMGs only on the tube buffer board.

As for those .1% Philips resistors, I have found IRC's .1% is less noisy. For general high precision purpose, I use mostly IRC. Good price, too. .1% Philips are hard to get here.
 
Dear finneybear,

thanks for your advise.

For your questions I ask for some of the big dealer already.

They said most populare 1% 25~50PPM will made in China. But the precision series or another higher grade as the photos show 0.2% 10ppm will not made in China.

I got 68Ohm of the 0.2% metal film resisters sample already & try to use in the I/V of the kit, it really very good. The black one is also precision but non-inductive. So the precision grade, non-inductive one & the 0.2% for I/V will use in the ver.II kit.

thx

thomas
 

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