SOLD to a good home! Okay, this is the only one of these in existence that I am aware of… Though Craig did make at least 3 different prototypes in this kind of chassis that got into the wild: 1. Zana Deux stuffed into one chassis (he eventually made the Zana Deux design with an external power supply) 2. 2A3 prototype 3. 6B4G prototype Craig agreed to sell the prototypes to his trusted tester/listener in the community (Mikey01) after his help. Here is the thread where Mikey01 was selling the prototype that became the Zana Deux: https://www.head-fi.org/threads/the-original-zana-duex-protype-handbuilt-by-craig.544011/ You can see I posted there in 2011, trying to track down that amp. Here is a Trader Feedback post showing Mikey01 sold a 2a3 prototype: https://www.head-fi.org/threads/mikey01.75731/#post-2973978 I tried again several years later to see if I could find the Zana Deux prototype and I finally got in touch with Mikey01... He had one last prototype and it is the one that you see here below: This prototype is a 6B4G prototype amp with (2) 6J5 driver tubes in a Moth Audio chassis. The idea behind Craig using these tubes is that NOS versions of these are nowhere near as expensive as the “usual” driver and output tube types you see in an amp. Driver tubes = Phillips JAN 6J5WGT (2 of these = 1 6SN7) Output Tubes = Ken Rad JAN-CKR-6B4G Ampsandsound uses the 6B4G in their statement amp, along with a 6SL7 instead of 6SN7 or two 6J5 tubes (which equals a 6SN7): https://ampsandsound.com/products/rockwell Ampsandsound also say “The motivation of the Rockwell is to provide access to the wide availability of NOS tubes and give the warm mid-range bloom that is at the heart of single-ended direct-heated triode designs.” Craig did most of his testing with HD600 back in those days (okay almost all days) and so this amp is very lush/warm and great with HD580/600/650. PLEASE NOTE #1: This is even warmer/lusher than the Zana Deux (and definitely warmer than Zana Deux Super). @Bill-P has heard this amp. He owns a very warm OG Zana Deux that I used to own. And he says this amp is even warmer. PLEASE NOTE #2: There is a little low-level noise when no music is playing, which is a reason that all Zana Deux have external power supplies. Craig already went through the prototype years ago and there is nothing to do to remove the slight noise floor. “There’s nothing you can do about it…just enjoy it.” PLEASE NOTE #3 (most important note): I promised Craig a couple of things a long time ago (and I think there might have been some 18 year Oban involved to even have him look at it) NEVER to bug him with the amp again (wasn’t a usual practice for him to even sell any prototypes and he didn’t make any money on this. Not to sell it and have it come back to him later with ANOTHER owner <ever> asking to have him work on it. SO: if you are okay with the low-level hiss + lushest EC sound (bit rolled at top) + you promise never to speak about this amp to Craig (or ask him where/how to work on it)…DM me. When I have considered selling it, I have “tested it” to make sure it works. And then I don’t want to sell it. I haven’t put many hours on it (have usually had a lot of set-ups rotating for different reasons). Just tested it and it still makes me happy to listen to HD6X0 series headphones. It is working! (Prefer someone in the Bay Area if possible so we don’t have to ship...) SOLD to a good home!