400 buzz ; need help

jerry harkins · Post by **jerry harkins** » 2 Feb 2002 6:47 am

I have a nash-400 that sounds great; but after it has been on for about 1hr it develops a buzz that seems to come from the amp head, not the speaker.this does'nt happen until it heats up. has anyone else had this prob; ?

Bill Crook · Post by **Bill Crook** » 3 Feb 2002 2:45 am

As you said:

seems to come from the amp head,

I would check the power transformer. It sounds like it's beginning to vibrate at the 60 cycle rate of the A.C. line after it gets warm. Try tighting up the screw and tap set at the corners of the txfmer. Or mabe the windings have become loose, in which case disassembly of the device (transformer)will be needed to remedy the problem.

I must caution tho,if you arn't confortable in pokeing around your amps inards, I would take it to a repair shop and ask them to look at it.
[This message was edited by Bill Crook on 03 February 2002 at 09:09 AM.]

Mike Brown · Post by **Mike Brown** » 5 Feb 2002 6:23 am

Check your reverb ground(if the reverb circuit is on when this occurs). This could cause the symptom. Also, it could be the power supply regulators.

I would think that the power transformer would be the last component to go south, but it could(but is rare).

Let me know if I can be of further assistance.

Mike Brown
Peavey Electronics Corporation