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oscillation in power supply filter caps

Hello, I have two VTL 225 mono blocks that I just got and I feel an oscillation in the both of the filter capacitors on one of the amps only. They were made for VTL and have a value of 3800uF and 400 vdc. Could the caps have gone bad, I have ordered replacements for both, 4900uF at 400 vdc as the units I'm sure are 30 years old. Any thoughts?
128x128hoghead1
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noromance's avatar
noromance
9,766 posts
 
If the caps are bad, there could be an increased load on the transformer causing it to vibrate.
glennewdick's avatar
glennewdick
1,658 posts
 
also one of the down stream components could be failing causing the circuit to oscillate this could potentially do serious damage so if in doubt take it to a local tech. 
millercarbon's avatar
millercarbon
12,531 posts
 
You are right to replace the caps. Hopefully the caps you ordered are not merely electrically the same but "designer" ie better sounding. Cheap caps do indeed sound cheap. Swapping out caps for higher quality is one of the surest, easiest mods you can make. Probably second only to diodes.

Anyway, swapping them out would be a good time to check those transformers. Some are bolted straight to the chassis. If that is the case you might want to try putting O-rings or rubber washers between the transformers and the chassis. Or if the VTL already has them they will be hard, maybe even cracked after 30 years, so there you go.
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