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[AMPS] tank spark discharge

To: <amps@contesting.com>
Subject: [AMPS] tank spark discharge
From: W8JI@contesting.com (Tom Rauch)
Date: Sat, 11 Mar 2000 15:25:40 -0500
> In my 8877 home brew amp, when I turn it off about a second after I do, I
> hear a little 'tink' of a spark from the plate tank area.  I traced it to
> a little spark which travels between the C2 end of the plate inductor and
> ground on the C2.  It jumps about 3/8 of an inch. I suppose it has
> something to do with the collapse of the 'magical fields' in the tank
> circuit and no doubt reflects the 'Q' of the tank.
> 

It sounds like the "safety choke" is defective, or perhaps missing.

Without a dc path to the chassis, when you turn off high voltage 
the blocking cap will discharge into the tank. That can cause 
something to arc.

That's one reason all amps need a good dc path to ground in the 
tank circuit at all times.
73, Tom W8JI
w8ji@contesting.com

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