It's an interesting project that I thought about doing myself. I also thought about building a Tape Project preamp for my RTR. Haven't gotten to it yet.

Here's a youtube vid of someone who built the little Pass Labs amp.

https://www.youtube.com/watch?v=DpzTZ1oPYt0

I think it's great that Nelson Pass takes the time to help the DIY'er like he does.

I've done a few. They sound pretty good depending on what components you chose to use but I personally didn't keep them very long. I probably should have for an office setup though. I ran them as monoblocks.
https://i.ibb.co/PjFBqbx/IMG-9848.jpg

https://i.ibb.co/Hh8cv7D/IMG-9627.jpg

Puma Cat, can you describe the sound difference between Bridged and Parallel?

Also, you mention premium parts - what are those parts?

Thanks, Steve

Never ran 'em as parallel monos.

As for the premium parts, check the ACA Premium parts build thread at DIYAudio. I just used the parts that TungstenAudio did in his thread (at the beginning of the thread).