This is pretty loud.
And as I said, it seems to be eminating from the PSU... As in you can hear the power transistor on the -15Vrail whining away, if you've got the audio out disconnected.
But it manifests on the audio out as well. Round about 5KHz I reckon.
On Thursday, June 11, 2015, 'Stephen Parsick'
wavecomputer360@... [yamahacs80] <
yamahacs80@...> wrote:
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I recently read about a modification that was done by Kent Spong which involved re-routing the cable loom because it would produce some kind of high-pitched whine. Maybe Kent could elaborate on his?
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Mine does that as well but it's only audible when playing lower notes.
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Stephen
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Hi
Still having issues with this CS50 PSU.
I've got a horrible high pitched whine all over everything. If I turn the amps off, I can actually hear this noise emanating from the PSU.
If I put a probe on the lines, I've got oscillation on both the + and -15V lines. Much worse on the -15V line.
I've recapped it, changed all the transistors, and diodes (Apart from the rectifiers)
Changed the 4458, but no change.
What's really odd is that if I touch the anode of the -15V zener (Opamp supply) with a scope probe, it collapses the Opamp supply.
Also... If I remove voice cards 3 and 4 from the rack and the problem goes away... even though they're still connected to the power.
Any incite, or suggestions? most welcome... I've got to get this thing sorted in a couple of weeks, so a client can use it on a session. :-s
