Class-A Williamson Vintage Hi-Fi amps

I finished a repair of a Knight KB85 stereo amp, and found it to be a great warm amp, 

very magical sound, typical of the great 1950s era of Hi-Fi

These older Hi-Fi amps have fantastic output transformers and circuits designed to put
out a wide range of frequencies, flat response, and small amounts of phase shift.

I am surprised when I crank one of these amps up and hear really deep bass notes come
out of the Wharfdale as most guitar amps have no real bottom end and are tuned
toward highs out mostly as guitars need lots of high boost.

Here is some of the fun wiring underneath, and me measuring everything without
melting one of my test leads while around the 485 to 500 volts on the plates of the KT66
tubes. I tested the amp with 6l6gc and these amps will run with EL34 tubes, but vintage KT66s
are super smooth and very rich magical sweet sound.

These tubes were invented by the English as a high voltage version of the 6l6g for their
super-williamson circuis that became the Heath W-5M amps and others we know
today.

So the KT tubes are High-voltage versions of 6bq5, 6ca7, and 6l6 tubes and EL tubes are
European versions of American tubes for serious High-Fi gear.