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Output transformers for DACs

I just wanted to send out a note for anyone thinking about the AG/CU transformers.

I have been using the original CU/CU 1:4 transformers (with the low-pass filter) with my Ian Canada stack for a couple of years.

It's a significant step-up using the 1:15, with no LPF and AG wire. Clearer top to bottom, higher resolution in the midrange and vocals (which added a nice dollop of realism) and what appears to be a darker background.

A worthwhile upgrade and I'm likely to order another set before he runs out of AG wire for an AD1862 build. The best bit about buying stuff of Ivan, is his helpfulness and responsiveness is excellent. Extremely trustworthy.
 
Thank you Seb for kind words!

Somewhat quieted down the activity ... Meanwhile I am trying to record my home system on microphones. To your attention a short track "Percussion improvisation". DAC on 1541A, output stage on my transformers, SE amplifier on 845 tubes, DML panels + Heil tweeters (HQP).

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WOW! What a sound!!!

Congratulations!
 
I have been using Ivan's output transformer pair on my DDDAC 1794. I also own a pair of Cinemags 15/15B trafos, which I was using with this dac till a couple of months ago. Since, then I have been using Ivan's trafos and I am super happy. I will keep this post short and provide a detailed review at a later time. However, even in summary, I can say that it is totally worth getting his trafos. I did a blind buy and have 0 regrets. The primary reason for me was wanting a hotter output for my dac and I could not afford the more expensive options that were available. I had detailed discussions with Ivan. He took the pain to understand the working of my DAC, studied the circuit and did some simulations at home. When he was convinced, he asked me to take the chance and I did. Boy, am I glad I took the plunge. I am still trying to work on the resistive loading to find the sweet spot but in short even with the same output as I had with Cinemags, i.e., 2.4Vrms, I get a more analogue, more spacious and a richer sound. A friend of mine who is only into vinyls and never cared much for my dac or digital playback, took notice of how good the system was sounding once the dac was paired with Ivan's trafos.

Now, the biggest point I want to mention is that not only are Ivan's trafos amazing, he himself is a super guy to work with. He is so friendly and helpful. He takes interest and cares for his customers. Honestly, I consider him as more of friend now.

I and 2 of my friends who heard his trafos in my dac were so convinced that we have already placed an order for 3 more of his MC SUT trafo pairs, which we are eagerly waiting for!!

I wholeheartedly recommend his trafos for dacs. Once I am settled with the trafo loading, I will recommend the same to other DDDAC users as well who are on a budget and don't want to consider buying 700-1000USD trafo pairs. Ivan's trafos are amazing.
 
Thank you Kartick, I am really appreciate your feedback and thoughts!

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My precious :djinn:
 
I have already written earlier that I use low-valued resistors as current-voltage converters before transformers. But in this case, the question of such a resistor quality is always arose. And if this issue can be solved on "small" transformers by transferring this resistor to the secondary coil, then on larger transformers this trick works worse, since the transformers are excessively damped. I tried a lot of different resistors, but my own resistors worked best. My DAC is really close to analog source now. The burn-in period takes more than 100 hours for such resistors.
 
It is a wire wound resistors made from a high-impedance wire cuts (manganin, constantan) using non-inductive winding technique and metal welding for leads (instead of pressing caps/soldering). Can't show photos right now as I am still searching the best enclosure design. Something tells me that the best for these resistors is to place them right inside the transformers. Pros - the shortest path from i/v conversion to transformer and EMI shielding, cons - no way for gain adjustment (for increase at least).
 
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I had detailed discussions with Ivan. He took the pain to understand the working of my DAC, studied the circuit and did some simulations at home.

I think that's what makes Ivan amazing to deal with. He has answered 10's if not a 100+ questions from me and studied several iterations of my amps, speakers, source and gain strategy for my system. Strongly recommended.
 
Hello, I bought a pair of transformers without intermediate tap last year. Can I use them in modern current mode DAC chips such as pcm1794? I think the middle thread is completely unnecessary, just like my picture.
 

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