BAD Buzz with SWR Bass-350

[noob2amps]

I'm pretty new to diagnosing amps so I'm looking to some of you more experienced people for help.

So here we go:

My SWR Bass-350 has a HORRIBLE buzz problem. I have figured out that the preamp is not the problem. There is a balanced XLR output that runs through the preamp but not the power amp. And it works perfectly.

As soon as I plug into the speaker cable outputs or the Speak-On outputs, the buzz ensues.

So I'm wondering what it could be in the power amp that would cause such a problem.

The bass will still come through, but there is just an obnoxious buzz behind it all, practically unbearable.

Any info would be appreciated.

[Enzo]

Your power amp needs two power supplies to run - a positive and a negative. I don;t recall on yours, but I would guess 50-80v on each. If the filter cap fails on one - or both - then that smooth DC is no longer smooth and there is intense hum.

It is more likely the solder under the cap has failed than the cap itself being bad. But they do fail. I am talking about the two largest filter caps in the amp.

[noob2amps]

Thanks man. I'll check it out and let you know how it goes.

[noob2amps]

YEP!!! That did it.


Thanks man, I really appreciate it. I'm glad I got this SWR back in action. It is loads better than my Kustom 250.

Peace