Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Leevi on May 06, 2018, 10:29:37 am
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I have been adding a Vibrochamp type cathode tremolo to a 5D3 circuit and after several tries the best point
seems to be the PI cathode.
http://el34world.com/charts/Schematics/files/fender/Fender_deluxe_5d3_schem.pdf
http://el34world.com/charts/Schematics/files/fender/Fender_Vibrochamp-AA764-schematic.pdf
Since the voltage raises on the cathode too high on full intensity the tremolo signal will dampen quite heavily.
I have balanced the situation by decreasing the 1.5K PI cathode resistor to 1K.
Do you think this will cause some bad consequences sound wise?
/Leevi
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IMO, the best option would to adapt the 5E9A tremolo to the 5D3 circuit.
http://thevintagesound.com/ffg/schem/tremolux_5e9-a_schem.gif (http://thevintagesound.com/ffg/schem/tremolux_5e9-a_schem.gif)
You might try tying the PI cathodes togther and use a common 750 to 820 ohm bias resistor. Interject the LFO signal to the joined cathodes.
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I don't see a big difference between Vibrochamp and 5E9-a tremolo.
Furthermore I have made some changes in the tremolo circuit in order to prevent thumping.
You might try tying the PI cathodes togther and use a common 750 to 820 ohm bias resistor. Interject the LFO signal to the joined cathodes
Might be worth to try
/Leevi
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How did you find the result?
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How did you find the result?
~OK, maybe not the strongest one but a useful tremolo. I had to tune the intensity down in order to prevent thumping.
A 22n cap from the plate of the tremolo tube to its cathode eliminated the rest of the thumping.
/Leevi