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Re: Any.. SuperAmp Vibrato pump cure?

10/21/2004 4:08 PM
moocow	Re: Any.. SuperAmp Vibrato pump cure? I worked on a blonde Bandmaster that had a horrible thumping problem and most of it was caused by bad filter caps in the power supply. After those were replaced, the amp still thumped so I used my oscilloscope to figure out just how much intensity the circuit really needed to operate the tremolo circuit. It turns out only a few volts need to get to the circuit but the oscillator was delivering about ten times too much voltage. I changed the stock 8.2M resistor/10M intensity pot to 4.7M/250K and the thumping was nearly gone but the tremolo intensity was still good. I don't know why Fender decided to use so much oscillator signal, but they didn't need to.

10/21/2004 4:08 PM

moocow

Re: Any.. SuperAmp Vibrato pump cure?

I worked on a blonde Bandmaster that had a horrible thumping problem and most of it was caused by bad filter caps in the power supply. After those were replaced, the amp still thumped so I used my oscilloscope to figure out just how much intensity the circuit really needed to operate the tremolo circuit. It turns out only a few volts need to get to the circuit but the oscillator was delivering about ten times too much voltage. I changed the stock 8.2M resistor/10M intensity pot to 4.7M/250K and the thumping was nearly gone but the tremolo intensity was still good. I don't know why Fender decided to use so much oscillator signal, but they didn't need to.

Replies:

Greg Simon Moocow, which trem circuit is that ... -- 10/21/2004 6:02 PM
Frid Moocow, thanks for detailled inform... -- 10/25/2004 2:13 AM