[Milsurplus] Super Pro Help! - Transformer Needed

[Howard Holden]

Bruce, have you tried CFZM 740 in Toronto? You should be able to hear them 
day or night. They had some pretty good stuff (40s 50s 60s etc), at least 
through 2010.  I used to listen to them back in NJ at night, after WVNJ in 
NJ decided to abandoned the great music and went talk.

Howie WB2AWQ/7

-----Original Message----- 
From: Bruce Gentry
Sent: Thursday, September 25, 2014 8:07 PM
To: Milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] Super Pro Help! - Transformer Needed

The commercial SPs had very good audio. I have an SP-400, and it sound
great, I just wish there was something good to listen to on AM around
here:( .  I fear an AudioPhool got the transformer from yours.  I faced
the same problem with an HRO someone had converted to one chassis,
ripping out the push-pull to make room for a power supply.  I solved it
with a phase inverter autotransformer from an old early 50s tube car
radio (Buick or Cadillac are the best bet) and an output transformer
from a table radio or  car radio. The center tap of the autotransformer
goes to ground or bias, whichever is used, and the ends to the grids of
the output tubes. The drive is applied to one of the grids, and the auto
transformer inverts and drives the other grid.  I used the primary of an
output transformer from a table radio as a coupling choke in place of
the driver transformer primary, and coupled the audio from the 6F6
driver plate to one of the output grids with a .2MFD condensor. It
sounded very good, and certainly better than silence.  If you make a
bracket, you can mount the two transformers and the condensor in the
same place as the original and preserve the chassis for the time when
you might find an original driver transformer.

       Bruce Gentry, KA2IVY


On 9/25/14 9:32 PM, Robert Goff wrote:
> Picked up a Hammarlund Super Pro with PS at the last hamfest.  I'd
> really like to get this one up and running since it is the 200X
> version covering the BC band and 160m.
>
> The one thing missing, strangely enough, is the audio INPUT
> transformer.  This is single 6F6 to push pull 6F6's.  A look through
> my junk box yielded nothing even close.
>
> Anybody have a junker Super Pro with this transformer?  It's T-7 on
> the schematic in TM 11-866.
>
> Thanks,
> de Robert W7MKA
>
> PS.  This particular receiver, although it has civilian markings does
> have orange Signal Corps stamps and MFP varnish - applied (as the
> stamp says) Jan '52.  Panel is black and that seems to be the original
> color.  I'm guessing this was a very late pre-war production?
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