2. amps-preamps
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Need help to trouble shoot the noisy amp.

Gentlemen,

Not too long ago, I bought a pair of hybrid monoblock amp. One is dead quiet and the other is noisy but still plays good music. 90% of the amp is point to point wired so very easy to compaire the two. The noisy one is also running bit hotter and vibrates bit more on my touch.

Upon careful inspection, I've noticed that the power supply wires are connected (bunched up) differently. The quiet one is joined with (thick red + brown + black) & (thick white + white + light brown) combination. The noisy one is joined with (thick white + brown + black) & (thick red + white + light brown) combination. It has one big toroidal transformer and on small one connected to the input tube.

Could this be the problem? All other wirings are same on both. I'm tempting to re-wire the noisy one to see what happen. However, I don't want to distroy the amp either.

Big TIA for your kind advise....
zt000
albertporter's avatar
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albertporter
4,949 posts
 
Ask the manufacturer of this amp before swapping anything. You could harm it (or worse), yourself.
gs5556
1,235 posts
 
If you cannot identify a problem, you cannot fix it. Please leave it alone. Power supplies are dangerous even with the unit disconnected (those big capacitors can pack a lethal punch).
audphile1's avatar
audphile1
5,159 posts
 
did you contact the manufacturer for advise? I wouldn't think that the color of wires is important. Most likely it's a bad transformer. If you put your ear next to where the power supply is on this amp and it buzzes and the other one doesn't, my guess would be that it's a bad transformer.
clio09
3,355 posts
 
Perhaps the best thing to do is go back to the manufacturer and provide the same description and ask the same question. Are the amps consecutive serial numbers? Who is the manufcaturer?
metro04
222 posts
 
Zt000,

I agree with albertporter about calling the manufacturer first, as it just takes a few minutes to verify. If not obtainable, and you have even basic electronic trouble shooting skills, and can locate a cheap volt meter (Home Depot, Radio Shack, etc), at least take some measurements before swapping the wiring. Mr. Porter and Gs5556 are right about their warnings, so, at least verify and discharge any HV caps before tinkering.
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