Pushing the limits of TDA1543 NOS DAC

[le´flu]

Hello Peter,

thanks allot for sharing. Just some questions at the moment...
right at the beginning, what brand is the black five-pole connector from
psu to main circuit? And What are those bib black ´lytics on the DAC.
board?

Greetings ulf

[Peter Daniel]

The connectors are from Switchcraft (Multi-Con-X), digikey part# SC1221 (for female cable mount).

The caps are BG FK 2200/35 and BG N 1000/50, the latter can be replaced with BG N 470/16

[le´flu]

okay, GREAT...thanks allot

As my whole System is unbalanced, would you recommend building
the balanced version and use it unbalanced?
Why are you not using any output-caps in your version?

Greetings Ulf

P.S. forget about the stupid questions about outputcaps...found all the answers :-(

[Peter Daniel]

If the system is unbalanced, there's no reason to built the DAC balanced, UNLESS you are using TVC which can convert balanced signal to unbalanced with the advantage of eliminating coupling caps because of zero differential offset (the 4V outputs from a DAC cancel each other when connected to primaries of the transformer)

My amps are also unbalanced.

[le´flu]

Okay...
well i don´t have TVC but an Valve-based unbal- LinePre
But there is the possibility to use an input from bal. via
inputtransformer to unbal. Would that be an upgrade over
just using unbal. DAC directly into the unbal. pre?

Greetings ulf

P.S. What do you thing..how many TDA will be needed to
find a matching pair for using the sym. DAC

[Peter Daniel]

I think transformer may be introducing as much coloration as quality caps. It's really hard to say what's better unless you compare it directly.

The guy for whom I converted DAC in post# 21 still raves about it and it's unbalanced DAC.

I sort chips in a circuit and takes at least 20 pcs to find a reasonable match.

[le´flu]

Just because i´m curious, Peter at post 24 what for is LED
S1 S2 and p on the front?

Greetings ulf

[Alexandre]

Originally Posted by Peter Daniel

Commercial or not, any input is useful and I appreciate your advice anyway. I might even try it one day.

Yes, try it, I have a correction to what I wrote earlier though. A single inverter might be needed as well. But the Tent clock output goes directly to the BCK of tda1543, which is the jitter critical input.

I will draw a schematic later.

Best,
Alex

[dantwomey]

Originally Posted by Peter Daniel

I think transformer may be introducing as much coloration as quality caps. It's really hard to say what's better unless you compare it directly.

The guy for whom I converted DAC in post# 21 still raves about it and it's unbalanced DAC.

I sort chips in a circuit and takes at least 20 pcs to find a reasonable match.

It would be interesting to see if Lundahl or Jensen had any transformers that would convert balanced to unbalanced without coloring the sound.

Regards,
Dan

[Peter Daniel]

The main reason I'm using transformer is because it is also my preamp. I mentioned it already that I can't imagine better passive line stage than TVC: it adds gain, converts balanced to unbalanced, unbalanced to balanced, allows phase reversal and of course, attenuates. There are kits available with stepping motors that allow adding remote control function. It also sounds better than most active preamps out there, if system is set up properly.

Jensen or Lundahl are certainly fine, but then you need additional line stage, which increases complexity and certainly affects the sound.

My preamps are based on S&B TX102 which are not available for diy any longer, however, I also tried Sowter and it seems as good as S&B.

I've built one such preamp for a local guy (using Sowter 1035) and he replaced his AR Ref 3 with it. Recently he asked me to build another one.

1035 offers balance control, if that is not needed, then 9395 would be a good choice: SOWTER ATTENUATOR TRANSFORMERS TVC VOLUME CONTROL

Those are probably not much more expensive than Lundahl or Jensen, but offer so much more...