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Smitty,
FWIW, I just set up a Marshall recently to feed the choke/screens/preamp from the PT CT of a FWB setup, it worked fine.
Triode Electronics has a new driver transformer with a 20K CT primary (10mA max DC imbalance) and four separate 20K secondaries (30mA max AC current capability per winding, I just learned this morning), which might work pretty well, for about $20. You could drive it with a P-P 12AT7 and parallel secondary pairs, loading each w/5K to the sec. CT - at least that's how I'd do it, but YMMV.
The Zener mod works by dumping excess cap-plate electrons to ground during the negative swing - I can't see any corresponding mechanism at work using transformer drive, and with substantial resistive loading it really shouldn't be needed.
Ray
FWIW, I just set up a Marshall recently to feed the choke/screens/preamp from the PT CT of a FWB setup, it worked fine.
Triode Electronics has a new driver transformer with a 20K CT primary (10mA max DC imbalance) and four separate 20K secondaries (30mA max AC current capability per winding, I just learned this morning), which might work pretty well, for about $20. You could drive it with a P-P 12AT7 and parallel secondary pairs, loading each w/5K to the sec. CT - at least that's how I'd do it, but YMMV.
The Zener mod works by dumping excess cap-plate electrons to ground during the negative swing - I can't see any corresponding mechanism at work using transformer drive, and with substantial resistive loading it really shouldn't be needed.
Ray
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