I had a fantastic time building this amp. It absolutely nails the VOX and Matchless tones I had hoped for. Pretty much powered right up without issue thanks to the well thought out layout and all the tips on the board here. I really only ran into 2 issues...
1) The impedance selector switch is really tight and the knob spins if I'm not careful. I'm guessing you have to index the knob stem? Maybe a dremel?
2) I am located in the West Hills of Portland and have 3 radio towers within a mile of my house. The amp was quiet on its own, but plugging in a guitar cable turned the amp into a fantastic FM radio. The click channel worked to change the stations, and I could fine tune reception with the tone knobs and cut knob
Anyway, I placed a 100pf capacitor between each input signal lug and ground. I then placed one 0.01uf cap between the input jack ground and the chassis. This worked perfectly to snub out any radio signal.
The amp is quiet when is should be, loud when I want it to be and sounds amazing. Great dynamic range and a wide spectrum of tones available from dark and warm to sparkling chime. Plenty of headroom as well.
A couple pics...