B&K Power Mosfet Replacements

[52 Bill]

I have a B&K Pro 600 power amp in for repair. All 20 Mosfets have cooked and burned. Surprisingly little else is damaged. B&K has supplied schematics but is unable to provide replacement output devices. The originals were matched quints of 2SK405 and 2SJ116's.

I figured that a 2SK1530 and 2SJ201 would be suitable for replacements based on published data. Matching may be a pain, but not impossible.

Has anyone here used these as replacements or repaired one of these amps?

[Steve Conner]

I believe these are lateral MOSFETs, the great white hope of the 1970s.

Hardly anyone makes lateral MOSFETs any more, except Magnatec and Exicon. They both do devices in the TO247/TO3P package that would probably work, but they're so expensive that the amp may not be economical to repair. Maybe you can get those Toshiba parts you mentioned cheaper.

You can't substitute the more common vertical MOSFETs like the IRFxxx series. They'll be thermally unstable.