First Watt F4

Not much in the forums about this Nelson Pass design. I've had this amp (actually an F4 clone) running into my Druids for a couple weeks now, and it's pretty stunning. No voltage gain, just current gain, which is a great match for high efficiency speakers and a relatively high gain preamp like my Jolida Music Envoy. Dead quiet at the speaker, and fabulous inner detail. I tried Monarchy SM-70 Pros, Sonic Impact Super-T, and Almarro A205A, and the F4 is easily the best of the bunch.

If you have Druids or any other over 100 dB speakers, the F4 is worthy of an audition.

And Nelson has just released the F5. The May 2008 edition of AudioXpress magazine has a full design description and construction instructions.

Can't wait to hear it performs.
Indeed, I find it interesting that the iterations of the First Watt series aren't meant to be improvements on the predecessor, but are completely different designs aimed at solving a different problem. The fact that he releases the schematics for DIYers to build is pretty amazing too.

Yep, Nelson only makes something like 100 of each F-series model and then gives away all the design info and schematics to the DIY community for free.

On top of that, he actually guides DIY'ers through how to make them on his Pass Labs forum on I've been waiting to see the feedback from the first builders of the F5.
Any impressions of the F5 yet?