Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on November 06, 2011, 06:08:00 am
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For those that can be interested in Tremelo circuits
I noticed that an old italian amp, the GEM Deluxe 10, used that tube for the tremelo circuit
thinking that someone can be interested on it I post the schematic here
Kagliostro
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TFT Kagliostro. Its always interesting to see different applications for 'non-standard' tubes. I note the cathode in that trem circuit is 1M, and the the max h-k voltage for that tube on the datasheet is 90V. I wonder what the cathode voltage is?
Also they have the trem output wriggling the grid of the 6V6 which is cathode-biased. When I tried that with a cathode-biased 6V6, it required the depth pot to be turned about 50 to 60 percent rotation before the trem kicked in. I wondered whether this was to do with the trem 'fighting' the auto-bias tendency of the cathode biasing in the 6V6. How much rotation does the depth pot require in this trem circuit?
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The 6AV6 is very similar to half an 12AX7. The 1M cathode resistor has to be a misprint.
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I've find the schematic looking for the schematic of the GEM Super Deluxe Reverb I've got few time ago at a flea market
Sorry I haven't hear one of that amps (neither the one I got, because it is broken)
About the 1M cathode resistor, who can say ......... there aren't original schematics available for those old italian amps
I'm looking to reverse engineer the circuit in my amp to have the schematic, but one error or a previous "unauthorized" modify is always possible ................. :dontknow:
I posted the schematic because it uses an odd tube and I know that here in the forum there are some guys interested in the reuse of this odd tubes
Kagliostro