Thanks for responses.

N_Cook : i know your website, thanks. It's interresting and I keep
your address. I find the colt 120 schematic. The build of the power
amp is the same of the viper. For this moment I did not test the amp.
The guy who send me this amp told me the compressor didn't work.
I will start the test today probably.

I didn't find some info archived.