[Boatanchors] general PA question

[George Morton]

IMHO the idle current of 100 ma sounds about right for
running in class AB1.  I run a single 4CX1500 and the idle current
is about 60ma and plate current at 1500 watts output is
in the 800 to 1000 ma rane.  Use the amp and be happy!  Brgds, Geo
----- Original Message ----- 
From: "W2HX" <w2hx at w2hx.com>
To: <boatanchors at mailman.qth.net>
Sent: Saturday, April 11, 2009 8:26 AM
Subject: [Boatanchors] general PA question


> Hi there. I am working on a power amp.
>
> The unit runs 2 4cx1500B's in parallel driven by 2 8122's in parallel.
>
> When idle (no rf input, no key) the plate current is supposed to be 0 ma.
> However, I seem to get about 100ma.
>
> When keyed at 1KW output, I get a little 750-800ma plate current. The unit
> is not supposed to exceed 750ma (800 absolute max).
>
> Does this sounds like a bias problem? Could an incorrect bias voltage 
> cause
> about 100ma too much current overall?
>
> Thanks
> Eugene
>
>
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