[Boatanchors] general PA question

[Gary Schafer]

Idle current on a single 4cx1500 should be 300 ma according the spec sheet.
60 ma or 100 ma is way too low.

73
Gary K4FMX

> -----Original Message-----
> From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-
> bounces at mailman.qth.net] On Behalf Of George Morton
> Sent: Saturday, April 11, 2009 12:31 PM
> To: w2hx at w2hx.com; boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] general PA question
> 
> 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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