[PlanetCCRMA] Re: Delta 1010 buzzing - update

[Joe Hartley]

On Sat, 24 Sep 2005 02:27:04 -0400
Mark Shuford <mark@tmhco.com> wrote:

> I wasn't around for the 1010 buzzing issue discussion which involved
> those capacitors. Was the advices to replace the caps w/ better quality
> caps? Was their any suggestion of using different ratings, particularly
> voltage? 

Richard Humphrey, who worked on the 1010s at CCRMA, said this:
  Yes, I've replaced these caps in several 1010s. The ones I replaced were 35
volts, if I remember correctly. This was clearly too low and I think the
replacements were 63V, but they may have been 50V. The circuit is a voltage
quadrupling bridge, and the input is 9VAC. This should require at least 48v
caps, (9VAC is about 12Vpeak),  and this assumes the 9VAC doesn't run hot,
which it almost certainly does.

  I think the problem here is they used CHEAP, rather than inadequate caps. 63
is plenty. If you replace them with better ones, you should be fine.

-- 
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       Joe Hartley - UNIX/network Consultant - jh@brainiac.com
Without deviation from the norm, "progress" is not possible. - FZappa