My F4 Guide

This is a guide to building a F4 using my boards, but you may be able to find some useful information here even if you use other boards.

The boards are based on the schematics from Nelson Pass's FirstWatt F4. You can get the service/user manual here: First Watt: Products: F4

You might want to check out the GB thread here: https://www.diyaudio.com/forums/group...gb-f4-pcb.html

PCB
Here is a picture of the pcb.


Errata
There is a trace error around R22. I have cut the traces on most of the boards I have sent - and the rest of the batch will be cut before I send them out.

These are the cuts which needs to be made:


And the green lines indicate where a connection must be made:

This can be done simply by having the leg of R22 go through the hole and to the side.

Schematics
F4R0.pdf

BOM
TBC

Output devices
You can use many different output devices for this amp, but the standard is Fairchilds FQA19N20C and FQA12P20C. They can be difficult to get your hands on, so you can use the IRFP parts instead. You can order a kit for the F4 from one of the diyAudio members here: Tech DIY Company Store


FAQ
I'll put the Q&A from the comments and thread here.