Re: amp vibrato (was: Little Walter was Re: throat vibrato)

[fjm <2738540@xxxxxxxxxxx>]

Mark Burness writes:
>Yes, the brownface Fender Concerts, Pros, Bandmasters >and Twins alter pitch.

This confuses me, I always thought the Concerts of that era used one of
2 versions of an oscillator circuit to vary the bias on the output tubes
which varied the loudness not the pitch of the amp.  I've owned both
versions of the Brown Concert, 5 and 6 preamp tube and neither one
varied the pitch of the output although both are much cooler sounding
than the modern Fender vibrato which uses an opto coupled resistor to
dump the signal to ground.  fjm