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Old 12th Jul 2019, 8:08 pm   #40
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Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 7,734
Default Re: Hacker GP42 and AL42 restoration help

Also when the amp is powered up with no speaker connected there is a strange squealing noise coming from the amp
Probably the output transformer protesting, don’t run it without a load of some kind, speaker, low value resistor.

Change those components, they will probably be out of specification, confirm the cathode components are good, they may be in that list from Michael to replace.

I am just wary of saying get two new valves at the price they are.
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