Amps
[Top] [All Lists]

[Amps] 8877 negative grid current

To: amps@contesting.com
Subject: [Amps] 8877 negative grid current
From: Conrad PA5Y <g0ruz@g0ruz.com>
Date: Sat, 14 Jul 2018 09:20:45 +0200
List-post: <mailto:amps@contesting.com>
Hello all.

I have a question on behalf of an Italian friend of mine.

He has 8877 amplifier for 2m and what sounds like some tired tubes. His 'normal' tube is a 3CPX1500. Recently he has noticed that when he tunes for maximum during tuning his grid current meter goes negative. I personally have never seen this on either of the two 8877 amplifiers that I previously ran. He has tried 2 other tubes which do not have this behaviour although they do produce less output than the tube that exhibits negative grid current. So I suppose the simple question is what causes negative grid current on high Mu triode like a 8877? Back bombardment?

73

Conrad PA5Y

_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>