Transformer DAC Experiment

[pftrvlr]

revintage,

I added 3.6K primary and 10K secondary resistor today. The result is very positive. The DAC sounds cleaner with better pace too. Now it is again the familiar lean and engaging CS chip sound. Actually this DAC has the best ever CS sound I can remember. I am satisfied and will keep it that way - at least for a while.

Next I will try transformers in my Twistedpear PCM1794 DAC. It is current output chip, I guess I will go with 600 or 150 transformers.

[revintage]

Hey p,
Normally a higher value secondary loading or only the Zin from the next stage sounds best for a transformer, but I don´t know in this particular case. Try different values to evaluate.

About current DACs and transformer, check this:
Passive output

[pftrvlr]

revintage,

Initially when there were no resistors on either side of the transformer, the output went directly to vin+ of an opamp follower. It sounded slow and muddy. Though I am sure how big an impact of the primary side resistors have.

I will try different values of secondary side resistors later on.

Thanks for the link to RAKK.

[Pano]

Interesting. Is the 10K across the secondary before it hits the opamp?
For sure the 3.6K across the primary should help - but I've never followed the transformer with an active stage, so don't know how that would sound.

Keep up the good work, let us know what you find.

[bbp]

have you ever test the performance of the output transformer?

[pftrvlr]

Originally Posted by bbp

have you ever test the performance of the output transformer?

Directly output of the transformer alone without resistors on either side sounded pretty bad.

I might try bypassing the OP Amp follower and see.