loud hum from power amp.

It may be some kind of grounding issue in your electrical somewhere. It has happened to me as well, where one amp is perfectly silent, and another amp buzzes / hums like crazy through the speakers. Some amps are sensitive, some not.

A quick check to see if there is a grounding loop / problem is by inserting a ground defeating plug into your outlet, then plug your amp into it. If the hum is gone, you have a grounding issue.

Tks 1markr for valuable input. Pls adv what kind of ground defeating plug you are refering to. where can i get one.

lift the ground on the amp by using a 3 prong to a 2 prong adapter plug. Any hardware store has them. If the hum goes away and I am sure it will, a search here on ground loop has valuable info. Good Luck.

Faziod

tks valuable input, will give it a try, keep my fingers crossed.