January 02, 2020

 

Do you want more tremolo? This could be for you. Read on...

This is a typical tremolo oscillator as found in many Fender amps, but the cathode resistor and bypass cap have been replaced with the LED portion of the optocoupler. This circuit produces a very strong tremolo effect without any annoying ticking, breathing, thumping, or pumping sounds. The circuit simply taps into the signal path and operates by smoothly shunting the signal to ground at the tremolo speed. The speed range is greater than the typical Fender circuit.

Intensity pot value depends on which part of the signal path you tap into. The 50K-RA pot shown works very well in a Fender AB763 amp. You may need a different value pot to use in another circuit. Some circuits may also require a series resistor between the INT pot and the signal path. Experiment to determine the pot value and/or series resistor value needed for a particular amp.

Trem-O-Nator
by sluckey 2/12/2019

 

I installed the original circuit in my '67 AB763 Bandmaster. Here's the schematic of my Bandmaster showing exactly how I installed it.

'67 Bandmaster documents

Sometime later I experimented with my Supro S-6424 tremolo circuit. The dual speed pot allows a slower speed that I really like. I have not used this circuit to drive the VTL5C1 but I feel confident that it will work just fine.

Link to the More Tremolo discussion on the Hoffman Forum.

Links to sound samples...

Bombacaototal used a different interface for his project on the Amp Garage forum. Notice the 100K Intensity pot (with 24K resistor) is placed in series with the VTL5C1. (Click here for link to the forum discussion)


Tubenit used the stock version for the Trem-O-Nator mod for his Carolina Special -RT amp.

Hoffman forum member ac427v used this interface on his Sumatra 25 Plexi-Vibroverb amp.

Hoffman forum member Platefire successfully implemented the TREM-O-NATOR in his Fender AB165 Pro Reverb. You can read about it in this thread on Hoffman's forum. And here's the pdf schematic/layout for the mod...

     Platefire.pdf

Hoffman forum member Dummyload added the TREM-O-NATOR to a stand alone reverb unit.  Here's the discussion and pdf schematic...

     reverb + tremelo - the fun way w/ 3 tubes. (el34world.com)

     Dummyload.pdf

Hoffman forum member Apexelectric replaced the standard tremolo circuit of his JTM 45 Bluesbreaker clone with the TREM-O-NATOR. You can read about it in this thread on Hoffman's forum.

Hoffman forum member Leevi added a solid state TREM-O-NATOR to his Fender 6G15 Reverb unit. You can read about it in this thread on Hoffman's forum. And here's the pdf schematic for the mod...

     Leevi_rt.pdf 

 

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