After 3 years of compiling parts and waiting for the spare time, I have finally put together my DAC. Design and photo of the build is attached. I still have to case it up and move it to my main listening system. So far it works :) It sounds very good and well worth the time invested in the project. More comments on how it sounds after I hook it up to my main speakers. Comments on design and layout welcome. Thanks.

The first attachment is not displayed properly so I think most people have missed it.

I am actually using a legato. I originally bought some transformers because I was curious to hear how it sounds after reading about other people trying it. I liked the sound of the transformer output directly from the Buffalo, but after I connect the Legato in between the two it sound much more dynamic. The difference being that the Buffalo is running in current mode with the Legato vs voltage mode with the transformers connected directly to it.

With a transformer, you need to keep the wire length of the output very short. I also wanted to power my headphones directly. Therefore the line stage I already had spare came in to the design. The Ventus would also be an excellent choice. I now have a DAC that had a great headphone amp and could also handle exotic high capacitance long interconnects.

In my own mind I justified having the transformer in the middle. It does the SE conversion (no opamp or nasty caps), has high CMRR (higher than a opamp?) which is important to make better use of a balanced DAC output, provides high frequency filtering as it can not pass through frequencies higher than say 200khz, lastly it provides ground isolation (the DAC + legato has a different ground to the linestage).

Someone with more audio knowledge than me would probably say that the marginal audio gains are not worth the extra costs. But it is DIY and I just want to have something different :)

Yes the balanced output of the legato go to the Jensen transformer.

Originally I had the Sigma22 powering both the Alpha20 and Legato. I then bought the Placid HD to have them powered separately but then also get ground separation. I picked the Placid because it was easily available in stock and I just wanted to try out Russ' new design.

sureshm: nice work. I am interested in transformer coupling the output of the Legato III as well, as this would eliminate the DC issue, and create a nice RF filter as well. I am interested in which model of Jensen you chose, and what are feelings as to whether the output impedance of the Legato (around 150 ohms perphase stock, mine is around 180 ohms) is low enough to drive the Jensen for low distortion, as my understanding is thta transformers need to be driven from a low impedance to achieve good perfrormance. I am also going to ask this question of the Jensen folks, and Lundahl distributors.
I run short cables, so no need for me to buffer the output after the transformer, but I ma wondering if I need to buffer it before the transformer. I also run balanced only, so no need ot do any converting to SE... just considering the transfomrer to get rid of the DC to G, and entirely block RF on the output.
I actually suspect that some of the "magic" heard from some tube gear, is actually a result of transformer coupling and not the tubes themselves: RF seems to have a way of contaminating signals in a subtle but annoying fashion...

Barrows: I chose the JT-11P-1 which is a 1:1 10k transformer. Since the impedance the legato sees is 10k I think it powers it easily. With a 600ohm transformer it would struggle. I have seen some designs with a buffer before the transformer to lower the impedance but my main concern was my interconnects being about 1m and Jensen advice to keep it below 45cm for optimum performance. Plus I get a headphone amp as a bonus.

I agree that some of the magic of tubes could be the transformer. I just liked the idea because I thought it might take the “digital edge” off and also breaks any feedback in the loop (although the legato is a no feedback design).