Power MOSFET for VCB/VVR
Toshiba 2SK2968 power MOSFET for VCB/VVR
For control of the B+ power supply voltage in an amplifier, there are several options. Amp Maker’s 0-190-275V power transformer allows 3-way power output switching at a low cost. But VCB/VVR allows continuous control.
At the heart of the VCB/VVR circuit is the power MOSFET. You can use several types, and Hall Amplification (the guys behind the original VVR circuit) use the NTE2973. That’s hugely expensive and hard to find in the UK, so I supply the equivalent 2SK2968. That’s also getting harder to find and I will find a substitute soon.
Most importantly, the MOSFET must be mounted to the chassis (or an equivalent heatsink), and for this you MUST use an insulator (mica, silpad, etc). This MOSFET comes with insulating film and M3 mounting hardware and is supplied in a special anti-static bag. MOSFETs can be destroyed by static charge, so be careful when handling.