Hum in Vegas 400

basilh · Post by **basilh** » 29 Jun 2001 1:04 am

What would cause hum in the reverb circuit of my amp ? It's only noticable when the reverb volume is turned up .
Baz.

------------------

<SMALL>Steel players do it without fretting</SMALL>

http://homepage.tinet.ie/~basilhenriques/

http://www.stax-a-trax.com/

Mike Brown · Post by **Mike Brown** » 29 Jun 2001 5:21 am

Most likely a loose wire in the reverb harness, whether it is at the molex pin connection on the bottom of the circuit board or an open pin in the Molex connector itself. It might even be a defective reverb pan. If the reverb pan has been relocated in the bottom of the cabinet, it could possibly be that the pan is too close to the speaker magnet.

Another possibility is that you might have a poor ground on the reverb pot itself.

Hope this help.

Ken Fox · Post by **Ken Fox** » 29 Jun 2001 6:12 pm

I just fixed a LTD 400 with the same problem. The hum was only noticeable when the reverb was turned up. I replaced the power supply filters and problem was gone. The filters were not quite bad enough to show up in the amp otherwise. I had just replaced the filters about 8 years prior to that. Life expectency is about 10 years for filters. I'm not saying that's your problem, but it fixed mine!!

Ken Fox · Post by **Ken Fox** » 29 Jun 2001 6:17 pm

Just an added note. This amp is old enough to merit a good check-up! Send the chassis to Peavey. You might see if they have a tone mod available for it, another good reason to send it down to Meridian. They'll do a great job and you'll find their repair cost as or more competitive than anyone else.