[Hammarlund] SP200/BCC779 audio xfmr

[William A Kulze]

Thanks, Chuck

I've found a Hammond at Antique Radio Supply (www.tubesandmore.com) that
might work. I don't know the Hammond no. but the ARS PN is P-T1608. It has
a 10k CT pri and 4/8/16 sec. It says it's suited to 6V6's, but it's only
rated at 10W. Seems like I heard the Super Pro can deliver 14W. I doubt
I'll be running this thing full blast, but I'd like a little room there.
If anybody has an opinion on this, by all means...

BTW- Do I have to do any changes in biasing for 6V6's? I've got a bunch of
them, and not so many 6F6's. I know they are close.

I'm looking forward to getting this going. It's in really good shape,
other that needing a bit of a cleaning. When I got it I thought it had a
dark green front panel. After putting it in my industrial parts cleaner
(kitchen sink) I found that it was a nice black wrinkle finish. You can
see a pic at http://pages.sbcglobal.net/bkulze/radio.htm . It was taken
before I had a digital camera, though.

I really appreciate all the help.

Bill Kulze

> Bill-
> Until I read your query, I did not know there had been an SP-200 version
with a single output transformer secondary.....but I just found an early
commercial schematic that shows just that, with a DPDT toggle switch to
select phones/speaker.
>
> For a replacement transformer there are several options (besides the
obvious - find a parts receiver)
> 1) Hammond #1650G provides output impedances from 3.5 thru 500
ohms...but
> the primary is only 6600 ohms, better suited to a pair of 6L6's than 6F6's.
>
> 2)Hammond #125D or 125E  could match your 6F6's directly to voice
coil...
>
> 3) The output transformer salvaged from any audio amp using 6V6, or 6BQ5
output tubes should work, again matching directly to voice coil.  If you
can find a PA amp that used these output tubes you will probably find a
500
> ohm output tap.
>
> There are guys around who will rewind a transformer, but the cost is
about
> equal to the hamfest price of an SP-200.
>
> Good luck,
> Chuck N7RHU
>