Hello AC'ers!
For Sale: DIY Class A, no feedback, no gain, Impedance Converting Amplifier based on (Firstwatt) F4!
*For those of you who do not know what the basis of this amp is, you need to read the Firstwatt website, so you don't accidentally buy something you cannot use*
Here is the backstory:
A few years ago, I decided I wanted to try my hand at building gear. This F4 was the first (and so far only) piece that I laid out the entire component without help. Yes, you can tell. Also, I built the "chassis" that you see in the pictures. Don't judge (ok, I guess you can), I had no clue!
I purchased the signal boards from Peter Daniels, but ended up point-to-point wiring the linear power supply myself. All the parts are very good to excellent. Antek torroid transformer, Dale resistors, Silmic II caps on the signal board and Nichicon KG Superthrough caps in the power supply. The KG caps cost $160 alone and were on sale when I bought them! This amp does not have balanced outputs, but the RCA unbalanced jacks are Cardas, the 5-way speaker binding posts are WBT. It has very nice rubber feet from Parts Connection. I did rob the power switch/fuse from an old preamp. It works perfectly.
The internal construction is a bit goofy, no doubt. In the pictures you can see my version of a star ground, and also the banks of resistors in the power supply that are floating above the caps, held in place by the stiffness of the wiring. Like I said, goofy, but it works.
Okay, so the elephant in the room: The chassis is poorly constructed. It does have commercial heat sinks robbed from an old computer power center. The chassis is solid aluminum. While I have holes drilled for hardware of some kind, I never completed attaching the top/front cover. (I kinda liked looking at the interior while it was playing.) It does have one-of-a-kind artwork on the top: FUGLYF4!
By this time, you are probably thinking this amp is a joke. I assure you, it is not. The bottom line: This amp is amazingly quiet and sounds terrific. I was using it in "boost" mode, taking the speaker outputs of low wattage tube amps to the inputs of the F4 and getting 25 watts of Class A SS with a tube vibe. The
only reason I am selling it is that I no longer have any of those flea watt amps, nor do I have a preamp that will swing the voltage to drive it (See the FW website for a schematic and information on the many ways this amp can be used and the preamp requirements). The clone F4 does run hot--like is it supposed to do--and this one is larger and differently shaped than a FW F4. I have no way to know, but I am guessing my power supply is stiffer than any other you may see, as it is certainly overbuilt.
I want to sell this amp to a good home. Preferably to someone familiar with building Pass/FirstWatt DIY gear. I am not going to embellish the chassis, it works, but you will have to attach the front/top.
This is pick up only, as it would not survive shipping in one piece (The caps are glued down to the bottom plate with hi-temp silicone.) I live in Bloomington, Indiana, and work in Indianapolis, so I could bring it either place. I may be at AXPONA 2016, but only on Friday.
Price, as is, $475.00 USD. Cash, US Postal Money Order or Pay Pal + 3% surcharge
Pics are not too good, I'll add some more soon. Thanks for looking!!!
