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Re: [Amps] Need reliable source for ACOM2000A tubes GU74B?

Subject: Re: [Amps] Need reliable source for ACOM2000A tubes GU74B?
From: Boye Christensen via Amps <>
Reply-to: Boye Christensen <>
Date: Sat, 26 Nov 2022 11:59:49 +0100
List-post: <>

I don't know ACOM2000 Amp how it is built e.t.c.

To take one tube out an test no 2 will be ok  with lower input PWR and Output PWR !

To disconnect Anode Voltage will be a fatal error, without any circuit protection

g2 will act as anode and posibly burn g2 then the tube is finish for all.

Most Amplifiert with tetrode has a safty circuit that discionnect g2 voltage if anode Voltage

is near g2 voltage.

73 Boye

On 26-11-2022 11:37, Rob Atkinson wrote:
Doesn't look like Array Solutions has any GU-74Bs at the moment but they
will test them for you for $35 each. Pretty good deal since they usually go
up one at a time and you are left wondering which one is still good.
Is there some reason why you can't disconnect the anode or remove one
tube and test the other one in your amp then switch to the other
socket to test the second tube?  Basically run a two tube amp with one
tube at a time.  It seems to me the dud will be revealed that way.  Or
both will be good or duds.  Save $70 plus shipping.

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