New build ultimate dumblebased amp (3):more depth in tremolo

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fjonkman
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Joined: Fri Sep 09, 2011 2:57 pm
Location: Netherlands, Rosmalen

New build ultimate dumblebased amp (3):more depth in tremolo

Post by fjonkman »

Since I build my amp and published it on this forum I didn't change anything in the schematic, but lately I noticed that my tremolo was not as deep as the old Fender-amps. But all these are not bias-driven tremolos and for me it wasnot clear if it was even possible to reach better results with my bias-driven tremolo without introducing a higher bias current. For two 6L6GC's in push-pull maximum dissipation is 30 watts. With a plate-voltage of 336 that means a bias current of about 60 mA to be safe.
I changed the 470K resistor from the cathode of V5b to the capacitor of 100nF to 56K. A lower bias current of 50 mA (tremolo off) gave me more room for maximum tremolo that drives the bias current up to about 70 mA which is not to much.
The result is a much deeper tremolo comparable with the old Fenders driven by a optical tremolo circuit that influences directly the volume on the power-amp input.
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