"Don Pearce" wrote in message
...


Apropos of the actual power supply. WIth valve voltages, during
development, I always had biggish resistors wired across the main
electrolytics to ensure that they discharged fairly quickly after
switchoff - about a couple of seconds was my target. These came out
for the final design, of course.

Many old studio amps had these bleeder resistors permanently installed.
220k seemed typical. They dissipated only a couple of watts, which was
negligible in the overall scheme of things, and discharged the 'lytics
well within the time it took the service man to remove the amp from
its rack, and take of the bottom plate.


Iain