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-   -   TDA1543 and CS8412 NOS DAC (http://www.diyaudio.com/forums/digital-source/75385-tda1543-cs8412-nos-dac.html)

Igla 7th March 2006 12:11 PM

TDA1543 and CS8412 NOS DAC
 
2 Attachment(s)
Hi all !
I have a question which bothers me for quite some time.
In allmost all TDA1543 NOS DAC schematics I've seen there are electrolitic caps on regulators output pins and also on pin 7 and 22 on CS8412 (for example 220uF and 22uF on NONOZ DAC III by Fedde).
I've built the last DAC without these caps and this DAC performs better than my other DAC with all those electrolitic caps.
I can't see any unstability or anomaly on my scope when these caps are not present in the circuit.

So...is there a special reason everyone puts them there?

Thanks a lot for the answer.
Regards;
Igla

poynton 7th March 2006 01:23 PM

Re: TDA1543 and CS8412 NOS DAC
 
Quote:

Originally posted by Igla

So...is there a special reason everyone puts them there?




According to some data sheets, a small capacitor next to the terminals of the regulator improves stability if there is appreciable distance from either the reservoir capacitor or the device bypass capacitor.

In digital circuits, it is better to use a small cap with low esr after the reg. and work upwards. With analog, the rule more is better seems to hold.

There should always de a decoupling cap as close to the device as possible.

Igla 7th March 2006 07:23 PM

Still; there is no need to use electrolitic caps next to CS8412 or at the output of the regulator.
I think that everybody puts them there because Kusunoki DAC has them (33uF on CS8412 and on TDA1543).
The only schematic I've seen this far without any caps on CS and TDA is Peter Daniel NOS DAC.

Elso Kwak 7th March 2006 07:27 PM

Quote:

Originally posted by Igla
Still; there is no need to use electrolitic caps next to CS8412 or at the output of the regulator.
I think that everybody puts them there because Kusunoki DAC has them (33uF on CS8412 and on TDA1543).
The only schematic I've seen this far without any caps on CS and TDA is Peter Daniel NOS DAC.
Hi, What helps more is a low noise analog supply for the PLL section of the CS8412.
:cool:


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