[AMRadio] Help Identify This Transformer and Choke
Donald Chester
k4kyv at hotmail.com
Sun May 15 13:02:11 EDT 2005
>
>>The PA-710 is possibly an older version of the CG-710 which is:
>>commercial grade
>>+/-1.5dB 40-10,000 cps
>>audio output, 20 watts,
>>push pull 41, 42, 47, 49, 7B5, 6AK6, 6K6GT
>>primary 14K/20K
>>secondary 500, 200, 16, 8, 5, 3, 1.5 ohms
>>case RC100 (round can with square flange)
That is correct. In 1948 UTC revised its transformer line. The PA (public
address) line was renamed CG (commercial grade), keeping the same numerical
suffix. They also changed case styles. The potted types went from the
rectangular black case to the familiar round grey can with the square flange
and terminals on the bottom. The open frame types were rotated 90 degrees
so that they became tall and narrow instead of low and wide. The actual
laminated core and coil assembly retained the same dimensions, just the
mounting hardware was changed.
I once rebuilt a defunct open frame PA series power supply choke by
disassembling the replacement CG counterpart I was able to acquire, and
remounting it in the original PA style end-bell casting I salvaged from the
burnt-out choke. When I reassembled and repainted it, it looked identical
to the original and I did not have to drill any new holes in the chassis for
the mounting screws.
Don K4KYV
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