@brbrock - I started conversing with Steve McCormack about the SMc Audio upgrade possibilities probably 10 years before I actually had them do work for me.
In 2012, SMc upgraded a McCormack TLC-1 passive/buffered preamp for me using design features based on their highly regarded VRE-1 preamp, including the exact outboard choke power supply, the Shallco discrete resistor (AN resistors) volume control, Lundahl transformers wound with Cardas wire, and special capacitors, connectors, and wire. I have run through about 20 well-respected audiophile preamplifiers in my system (a couple over $10K) and none of them sounded as good to me as that SMc TLC-1 Signature Edition. Several years ago, I decided I needed to have a remote control for volume and a digital display that I could see across the room. Steve still wasn’t putting them in upgraded TLC-1s (he may be now) so he helped me modify my preamp by taking the volume control out of the circuit and replacing it with two large Audio Note silver resistors so that the unit is now a unity-gain buffer without a VC. I run my DAC output into a custom made Khozmo passive unit (dual mono, single input/output, large display, remote), and then from the passive through the SMc TLC-1 SE buffer, then into my SMc Audio amps.
The amps started as two McCormack DNA-1 stereo amplifiers and then Steve and Patrick did everything they could (at the time) to improve them including using their new circuit boards, basically all new parts, and their gravity base. Pictures of the amps are on their home page (the black amps at the bottom of the first block of pictures). They sound outstanding to me and also do an excellent job of powering my hard-to-drive Aerial LR5 speakers.
I have been speaking with Steve and Patrick for a couple of years about their DAC and sent them an old,stock DAC-1 that I found on-line (had it shipped directly to them). I sort of forgot about the project and then a couple of months ago Patrick called and asked if I still wanted to do the DAC project. The result is better than I imagined. If you look at the picture earlier in this thread you will see they have a new board that they now use and have done a remarkable job on the power supply and upgrading parts. They also used their Gravity Base on the DAC-2. By all accounts I can find, the DAC chip is basically bog-standard, the DAC only accepts a S/PDIF input (coax), and the input must be limited (i.e., down sampled if necessary) to 48 kHz and 24-bits, but this thing sounds way better than I ever imagined it would sound. I have three DACs here now and what I can say is that, after just over two weeks, the SMc DAC-2 holds its own with the others, and maybe more. The other two both cost in excess of $10k. It is a very musical sounding DAC, a little different from the R2R DACs I have been using, but just as musical and very enjoyable to listen to.