New TDA1541 based DAC - mods?

[Dowser]

I cleaned out Studer CH of their spare S1 chips...CHF 38 each from memory One I have fitted is genuine, as are my remaining spares. While it’s still socketed, I may try a late Taiwan stock chip I have to compare at some point.

I’m happy to take your 1541 too, I’m in Switzerland though, so would have to pay postage as well - what date code is it?

 

[russel]

Got one of these http://rover.ebay.com/rover/1/711-5...0001&campid=5338728743&icep_item=192267358039 to play with, sounded a bit rough with stock components, so changed opamps to OPA2604, local decoupling added 0.22uf plus low esr electrolytics, added local decoupling directly to the pins on the upgraded to TDA1541A, from my stash of kosher devices. I had heard the 7220 was noisy and scope showed it was, 0.22uf plus 470uf low esr made a huge improvement, no hf oscillation was noticed on the supplies. been listening to it for a couple of days and it’s not bad, not bad at all.

 

[Dowser]

Just checked power rail strategy on this - dedicated regulator for the SAA7220, and one each for the 3 1541 rails too - not bad, although they could all do with some local decoupling.

However, the thing is using 270uF/16v Sanyo electrolytic output caps - seems weird to me - what happens if I drop 10, 22 or 100uF tants in there instead? Still sounds very good to these old ears

Thanks, Richard

 

[Mike P]

I know we don't necessarily have the same taste in coupling caps but I really don't like Oscons for analogue stage coupling or decoupling, they just sound wrong to me.

I'd definitely try some other caps in that position. My personal choice would be Silmics or Nichicon Muse Bipolar, if sticking with electros or Wima MKS2 if trying metallised films.

The two Oscons could be very usefully re-purposed for digital IC decoupling where they're ideal.

 

[a.palfreyman]

Please stop showing this sort of pron as it whets my appetite
AP

 

[IDM]

How is the I/V conversion done with these boards?

My TDA1541a DAC is completely home-brew with AD844 op-amps doing the I/V with the output from pin 5 (TZ). I recently tried stacking 2X AD844 (for each channel) with only pins 2,3,4,5 and 7 soldered together. There is in my opinion a big sound improvement to be had. There are threads on Diyaudio that describe the mod.

Cheers
Ian