I have wondered about that. There may be some improvement. During the time that
the single ended amplifier is approaching cutoff there is considerable
non-linearity. In a AB push-pull amplifier both tubes conduct during through
cross over and possibly improve the linearity. I wonder if someone can put it
to the test either by simulation or by actually trying it.
73
Bill wa4lav
-----Original Message-----
From: "Gary Schafer" <garyschafer@comcast.net>
To: <amps@contesting.com>
Date: Tue, 14 Nov 2006 22:26:36 -0600
Subject: Re: [Amps] Class A for AM
No. Push pull has nothing to do with amplitude linearity in RF service.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Robert B. Bonner
> Sent: Tuesday, November 14, 2006 8:16 PM
> To: 'Tom W8JI'; 'Gary Schafer'; 'KA5MIR'; amps@contesting.com
> Subject: Re: [Amps] Class A for AM
>
> Hey Tom, isn't that why they went to PUSH PULL finals with a link coupled
> output? Still simulates class A with a pair of class B finals...
>
> I think a couple nice 4-1000's glowing in the rack should just about do
> it.
>
> Modulate it anyway you'd like. Sometimes just sometimes the old way is
> the
> best way.
>
> I wonder if I could still build a link coupled final? The last time I did
> one was my second novice transmitter a little 6DQ6 25 watter.
>
> 4-1000's? Whoops the only things I have pairs of here are: 3-500's 8877's
> 3CX3000's and YC-156's drat fresh outta 4-1000's.. Oh and you guys had me
> all excited there for a minute.
>
> BOB DD
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Tom W8JI
> Sent: Tuesday, November 14, 2006 8:06 PM
> To: Gary Schafer; 'KA5MIR'; amps@contesting.com
> Subject: Re: [Amps] Class A for AM
>
> > Except in class A the input power never changes. If it is
> > set up for 6000
> > watts input in order to provide 1500 watts output @25%
> > efficiency then the
> > input power will always be a constant 6000 watts with or
> > without modulation
> > or carrier.
> >
> > When it is putting out 375 watts carrier the input power
> > will still be 6000
> > watts.
> >
> > So the dissipation would be 6000 watts minus power out for
> > any given output
> > power.
>
>
> That's the way I see it also.
>
> Since it should make around 50% on peaks it should make
> around 25% on carrier, and 3000 watts plus headroom of
> standing power should do it.
> It will just be useful output power minus standing zero
> signal dissipation.
>
> 73 Tom
>
>
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