"Phil Allison" wrote in message
...

** One maker of Mosfet power amplifiers (Perreaux of NZ) had a
major issue with PCB dust/fluff contamination - it made the amps
crackle loudly or even blow up spectacularly.

There were signal tracks that ran parallel along the main PCB,
spaced by about 0.4mm, that differed by 240 volts DC.

I remember Perreaux. I thought, with a name like that, their products had to
be dogs. Looks like they were.