While other tubes may do better, I've had good luck using AB1 807s in
VikingI/II/DX-100 class transmitters - they'll do 100% cleanly.
-Larry/NE1S
Gary Schafer writes:
Just remember if you are going to use a tube phase inverter rather than a
driver transformer the modulator tubes need to be run in AB1 and not AB2.
You can't run any grid current without a driver transformer.
This leaves out 807's as modulators as you can't get very much power out of
them in AB1 but they are fine in AB2 as they are used in most rigs. Dx100
etc.
73
Gary K4FMX
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:amradio-
[EMAIL PROTECTED] On Behalf Of Peter Markavage
Sent: Sunday, March 26, 2006 1:34 PM
To: amradio@mailman.qth.net
Subject: Re: [AMRadio] Modulator design needed
12BY7 drives the driver transformer which, in turn drives the EL-34's.
Build a phase inverter, like many of the Hi-Fi amps that don't use a
driver transformer to drive the EL-34's.
Pete, wa2cwa
On Sun, 26 Mar 2006 13:19:06 -0500 "Mike Sawyer" <[EMAIL PROTECTED]>
writes:
> Bob,
> I suggest you look at the schematics again. The output of the
> 5763 goes
> no where near the modulator. I don't have the schematics in front
> of me but
> I have done some extensive work in the audio section.
> Mod-U-Lator,
> Mike(y)
> W3SLK
> ----- Original Message -----
> From: <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>; "Discussion of AM Radio"
> <amradio@mailman.qth.net>;
> "Discussion of AM Radio" <amradio@mailman.qth.net>
> Sent: Sunday, March 26, 2006 12:59 PM
> Subject: Re: [AMRadio] Modulator design needed
>
>
> Mark,
>
> Take a look at a Heathkit Apache schematic, (TX-1), for ideas.
>
> There is NO driver transformer. The 5763 driver goes to the Mod
> transformer
> and the EL-34s feed it for audio.
>
> Bob - N0DGN
>
> -------------- Original message ----------------------
> From: "W1EOF" <[EMAIL PROTECTED]>
> >
> > I've been gifted a nice mod transformer so I can build a modulator
> for my
> > Johnson 6N2. I don't have a driver transformer so I'm looking for
> a design
> > which doesn't need one. I'm sure the schematics are out there, but
> I keep
> > finding ones with the driver transformer. Same with all my old
> radio books
> > that I've looked at so far. Can someone point me in the direction
> of a
> > good
> > design that is online, or one that you can share with me via
> email?
> > Thanks!
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