"Sub Zero" Low Voltage Submini Push/Pull Amplifier

[frequencycentral]

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[mojo2001]

Another cool design!

The obvious solution to the voltage quandry is the reverse filament trans fed by AC at the heater voltage.

A bit low tech but effective.

Or, for DC, how about a PWM DC-DC converter into a voltage tripler or quadrupler?

[frequencycentral]

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[mojo2001]

Since you are not running high volts, a HV mosfet is semi overkill. Motorola used to make nice 2 terminal CCS...not sure how much voltage would get thrown away across the device. Mosfet is cheaper, though, and those Motorola parts are obsolete.

Dirt common DC-DC converters go up to 28V, which would give ya twice as much wiggle room.

Or textbook RC voltage multiplier across any of these newfangled approaches would hook you up.

But you are talking to the wrong guy. I'm so old school I want octals in my projects!

[VacuumVoodoo]

The PI will be biased into cut-off. I would recommend to use boot strap bias scheme here.

[frequencycentral]

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[VacuumVoodoo]

The PI will be biased into cut-off. I would recommend to use boot strap bias scheme here.

Thanks - but can you expand on that idea a little please, maybe by modifying and re-posting my schematic?

Thanks again,

Rick

http://www.freewebs.com/valvewizard/cathodyne.html

[frequencycentral]

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