Have you thought about feed back destroyers ? I know Behringer make some and if they do, it is a fair bet other people do also !
If it is 60 Hz humm the problem may not be one a feedback destroyer or a noise gate can do anything about and the answer may be a get a power conditioner and make sure your grounds are good
[Edited by Dr_simon on 10-01-2003 at 07:02 AM]
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my toons Brought to you by Dr BadGAS
my toons Brought to you by Dr BadGAS