Thursday, December 4, 2008

Ampeg V4B bias mod

A bit of a test post really - trying out the photo upload.

This is the inside of a Ampeg V4B that had burned out the screen resistors. The pic shows a mod done I found in there done by a previous tech. Stock V series amps derive the bias from the B+ supply. The transformer next to the power tubes was added across the heater supply to kludge an independent bias supply winding in the power supply.

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