In <200207060110.g661Amx23986@nimbus.heaven.net>, on 07/05/2002
at 06:13 PM, Richard <2@mail.vcnet.com> said:
>>>>Some time ago a guy told me he was substituting the
>>>>4-400A tube in his Swan Mark 1 amplifier instead of
>>>>using the 3-400Z tube. He had a large supply of the
>>>>4-400A tubes on hand and said they were working very
>>>>well in the Swan Mark 1 even though it was designed
>>>>around the 3-400Z tube. Is this an ok thing to do in
>>>>the long term?
>>>>73,
>>>In g-g, at 0v bias, the 4-400A needs c. 3400V to idle at the requisite
>>>75mA.
>>
>>So add some bias already. <g>
>Adding bias to raise the ZSAC to 75mA/tube with 3000VDC would require
>connecting a 1A, 1 - 3 volt neg. polarity PS to the CT/cathode return.
[grumble-grouse] . . . Oh, I see, a trivial task.
--
wwd K2AME
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