next candidate - Stereo-vib GA-83S

[Rob Mercure]

For my next candidate of interesting circuit is the Stereo-vib (do you think Gibson really meants "vibe?") GA-83T on page 259 of the Gibson Master Service Manual. The tremelo circuit is "wild and interesting" and I'm not sure how perzactly the oscillator circuit hits the circuits on each leg of the 12AU7 split load phase separator (not using the term phase invertor as this doesn't feed the output tubes) before driving the 6CG7s. Unlike the last post where I was thinking "compressor" all along in this case I know it's a vibrato but I have trouble thinking out how the above described section works.

And I've got a few more Gibson circuits after this one - never really went through the manual before but Gibson really tried to carve out a niche as an innovator in amps - too bad the contractors who actually manufacturered the amps did such a bad job, for the greatest part, in creating a trouble free well built product. Fender was a bit "boring" but reliable.

Rob

[tubeswell]

Tis a strange amp indeed. The oscillator hooks into the cathodes of V5 and V6, which appear to be out of phase with each other? Would that be to cancel-out the background noise of the oscillator?