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Hi Gent's
This is my first post and I apologize in advance for showing up hat in hand with my first post. I recently completed a "low watt" 5F11 Vibrolux for a friend. Schematic wise it's pretty much stock except that required to change the output stage to use a pair of 6G6G tubes instead of 6V6. The bias circuit was modded to provide about -16v bias for the 6G6 tubes and of course the B+ voltages are lower across the board (in the 220v ballpark) to suit the requirements of the 6G6 tubes. The amp produces about 2.5 - 3 watts output.
The new owner loves this amp sans tremolo. Unfortunately he reports that the tremolo really distorts the output .. he compares it to the splatty sound that some pedals provide .. similar to what you hear in the first minute or of this vid:
My gut feeling is that given the BIAS voltage in this amp is roughly half what it would be in the standard 5F11 the trem output is more or less overwhelming the bias section and sending the tubes into an overdriven and/or blocking situation of sorts .. does that make sense ?!? I'm not sure where to start in modding the trem section to make this work.
I can post schematics and or gut shot etc it that would help. Note that the plate voltage on the trem tube is approx 133v and the bias is about 1v (.99v on pin 8) The components in the trem section are schematic stock at this point.
Any thoughts or ideas you have in this regard would be appreciated.
This is my first post and I apologize in advance for showing up hat in hand with my first post. I recently completed a "low watt" 5F11 Vibrolux for a friend. Schematic wise it's pretty much stock except that required to change the output stage to use a pair of 6G6G tubes instead of 6V6. The bias circuit was modded to provide about -16v bias for the 6G6 tubes and of course the B+ voltages are lower across the board (in the 220v ballpark) to suit the requirements of the 6G6 tubes. The amp produces about 2.5 - 3 watts output.
The new owner loves this amp sans tremolo. Unfortunately he reports that the tremolo really distorts the output .. he compares it to the splatty sound that some pedals provide .. similar to what you hear in the first minute or of this vid:
My gut feeling is that given the BIAS voltage in this amp is roughly half what it would be in the standard 5F11 the trem output is more or less overwhelming the bias section and sending the tubes into an overdriven and/or blocking situation of sorts .. does that make sense ?!? I'm not sure where to start in modding the trem section to make this work.
I can post schematics and or gut shot etc it that would help. Note that the plate voltage on the trem tube is approx 133v and the bias is about 1v (.99v on pin 8) The components in the trem section are schematic stock at this point.
Any thoughts or ideas you have in this regard would be appreciated.
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