I built the Ramsey 20m amp with mods and
heavy heat sinks and it has worked fine for
almost ten year now. I am driving it with a
Small Wonder Labs PSK-20, and keep the power
throttled back to about 13 or 14 watts due to the
duty cycle of the mode. I have both boards
built into one enclosure with a small fan and it turned out
to be a spiffy little project. Most of the time
I run the PSK-20 barefoot (QRP) but can switch
in the Ramsey amp with a switch when needed.
A couple months later I built the 40m version
using the same mods and precautions and on first
power up .....
WHOOSH it went up in flames. 
Literally flames.
Go figure.
I would not recommend them to anyone.I just got lucky.
If you want a nice QRP amp, save up your spare
change and get an HF Packer Amp. THree watts in,
40 watts out, operates 10m to 160m including WARC.
73, Ken AD6KA