G
Guest
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I have been interested in doing a vibrato circuit based on the ones used in Magnatone guitar amplifiers. I finally got around to breadboarding it and thought I would share the design with the forum. I poster the schematic here.
I ended up buying a sample of most of the varistors I could find on sale and just tryed them in pairs until I found some that worked reasonably well. There is a pretty narrow window of values that work on my circuit. Below a 20VRMS rating not much happens, above 30VRMS rating the signal gets killed. I settled for 25VRMS ones from Littlefuse (V39ZA1).
The audio signal is slightly frequency modulated to make a nice smooth vibrato, and it also modulates the amplitude for tremolo effect. All in all I am pretty pleased with this little circuit.
I ended up buying a sample of most of the varistors I could find on sale and just tryed them in pairs until I found some that worked reasonably well. There is a pretty narrow window of values that work on my circuit. Below a 20VRMS rating not much happens, above 30VRMS rating the signal gets killed. I settled for 25VRMS ones from Littlefuse (V39ZA1).
The audio signal is slightly frequency modulated to make a nice smooth vibrato, and it also modulates the amplitude for tremolo effect. All in all I am pretty pleased with this little circuit.