Cold solder joint???

[xr650jkallen]

I've got a soundstream reference 500s. In stereo mode for about the first 10 mins of play I get a funny noise out of my right channel. It seems to go away after the amp warms up. This has got me thinking its a cold solder joint, but if I put the amp in bridged mode the noise goes away, so this baffles me a lil bit. I've cleaned the switches which is a known prob. I haven't lifted the board off the heatsink to check for cold solder joints yet, kinda wanting some direction on we're to possibly look before tearing into it.

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[xr650jkallen]

It does it with the rcas disconnected also.

 

[wew lad 5,000+ posts]

99.9% chance you're overthinking it, check your power and ground. make sure those are clean as can be and a great connection.

it may be a bad amp, problems like this can be hard to diagnose

 

[xr650jkallen]

I put the amp on the bench today. There were no burnt spots and all the transistors checked out ok. My noise has somewhat calmed down, but while on the bench I noticed the left channel is weaker than the right. Im pretty sure its one of the feb boards, but im not sure which one is for the left channel. Anybody know?

 

[wew lad 5,000+ posts]

If you're dead set on the amp possibly being bad post om MAF or diyma in the amp internals help section

 

[xr650jkallen]

It still sounds great, I can just tell that the left channel aint being driven like the right. Thanks Mitchell I have been lurking around on diyma just haven't joined.

 

[wew lad 5,000+ posts]

No problem, there's just a bunch more people proficient in circuits than those here

 

[hispls 5,000+ posts]

It still sounds great, I can just tell that the left channel aint being driven like the right. Thanks Mitchell I have been lurking around on diyma just haven't joined.

You're dealing with a very old amp. Electrolytic capacitors fail and who knows what else has happened over time? It may be time to send it to a professional for restoration of all out of date parts. Correct me if I'm wrong, but that amp has to be 25 years old or so right?

 

[xr650jkallen]

The date on the board is 11/96 so its bumping 20 years. I might just have to send it off, I love the way it sounds.