[AMRadio] Modulator design needed


Peter Markavage manualman at juno.com
Sun Mar 26 13:33:45 EST 2006


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" <w3slk at uplink.net>
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: <rbethman at comcast.net>
> To: <w1eof at hamnutz.com>; "Discussion of AM Radio" 
> <amradio at mailman.qth.net>; 
> "Discussion of AM Radio" <amradio at 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" <w1eof at hamnutz.com>
> >
> > 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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