I have available a CFA3, built by Dukei here on Head-Fi.
This is a legendary amp with top tier performance and ridiculous value, built by the best builder here on Head-Fi. It has gobs of power and is ideal in particular for the AB-1266 Phi TC, but works well for other headphones, such as my Modhouse Argons. I've also used it to drive my single-driver speakers and that worked well too -- great bass. I have heard reports that using a tube pre in front of it (such as WA33 or Supratek Cabernet) sounds incredible, but I haven't tried that.
I think this build took me over a year to receive after being commissioned (good things are worth the wait).
I have just recently sent this CFA3 back to Dukei who looked it over, cleaned it up, fixed a volume pot issue, updated the internals, did a listening test, and sent it back to me. I have not used it since it was returned to me.
I originally purchased this amp for use with my 1266. Regrettably, I have sold my 1266, so I have no use for this amplifier. Even when I had my 1266, I didn't actually use it that much, so this amp has not been used much (less than 100 hours). I would keep the CFA3 anyway, but am selling to recoup funds and shelf space.
This is a single-chassis unit, no speaker terminals, non-stepped volume pot.
Asking price includes insured shipping and Paypal fee.
If you have questions, I can provide relevant exchanges between myself and Dukei.

As for a sound description:
Overall the best headphone experience that I have ever heard was a DCS Vivaldi One feeding into this CFA3 into a 1266 TC. CFA3 and TC is truly excellent for evaluating sources.
I would describe of the sound of the CFA3 as not warm and not bright, and smooth but incredibly detailed. It is a like a light shining into the darkest corners of the music to illuminate everything, but without a trace of being fatiguing, which is unusual. I thought it would have a similar tonality to the GS-X Mini (warm with bass emphasis) but it does not. It has Class A illumination rather than Class A warmth. The first time I received the CFA3, I hooked it up to my Holo Spring 2 KTE and 1266 and immediately cried. I then understood the true nature of the 1266. I do confess that I personally prefer in general a more "dark and mysterious" tonality as can be achieved with tubes. The 1266 while not bright is also definitely not "dark and mysterious", so while it is easily the most impressive and uncanny-valley-realistic-sounding headphone imo, it was also perhaps not the best fit for me for day-to-day enjoyment.

I will entertain trade offers (speaker amps included) but I am hoping primarily for cash.

Thanks for reading.

Paradoxper, I welcome your comment