[Amps] cathode to ground in tetrode amp

Bill Turner dezrat1242 at ispwest.com
Mon Jan 30 11:41:58 EST 2006


ORIGINAL MESSAGE:

At 08:13 AM 1/30/2006, Partain, Chuck wrote:

>>OK, getting into this more and more every day and learning. Looking 
>>at some designs on this GU-84b
>>amp, I see a lot if not most of the cathodes have resistance, some 
>>a lot(30k) some little (.7) to ground.
>>The screen grid and control grids are not grounded and have 
>>respectively ~350 and -150v on them.
>>
>>Why wouldn't it just essentially go to ground? what does the R do in series?
>>
>>thanks as always.
>>
>>KA1MWP


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

That design is a little unusual. Cathodes do not usually have an 
inductor in series with the ground lead and a resistor paralleled 
with that. Otherwise it appears to be a conventional "passive grid" 
circuit. I'd suggest contacting NI4L and asking him.

73, Bill W6WRT


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