cap across HT supply

[Alex R]

I just wondered... in a modern Orange head blowing fuses, I found a shorted 10n 1kV cap wired across the HT supply before the rectifiers - ie across the transformer AC output. What is it, an RF suppressor?

[PositiveNegativeMan]

Not sure if I am interpreting your description correctly, but I know that sometimes caps of this value were used to filter out unwanted high frequency ripple that may be lurking in the mains supply. Do you have a schematic? Is it on there as part of the original design, or is it something that somebody has retro fitted?

[Steve Conner]

Yup, it's probably there from the factory to snub switching noise from the diodes, that would otherwise cause the amp to fail an EMC test.

[Alex R]

Thanks guys - just checking that i had indeed taken the most economic route in clipping it out altogether...