[BC] WLS Tx History Update

[Warren Shulz]

The 317C3 has an active  5534 differential input.  WMVP-AM-1000  has an early 317C0 and the control circuits are K-logic (K101, K102...) and it is disconnected in deep standby.  Looks to be 1960 vintage.  That draughty designed lived for a long time as the 'answer' for AM.  Kevin at WJR was actually using the 317C3 for the sound performance vs DX50.  the 317 has a high amount of distortion (compared to the DX50) in the IM area and it would lead one to believe it to be objectionable.  But as I reported with DX50 on and 317 into load a blind test you can't argue the 317 is deficient.  If you apply a square-wave the 317C3 will reproduce it as does the DX. I suspect that is the reason it passes the ear test even thought the distortion readings in IMD area go from 1.3% to about 5-6 % for the 317.

The WLS one looks like it did when installed in 1989.  In the 1978 air (kept in place from MW50) handling design any outside air passed through a 12 inch deep pleated 48 x 48 bag filter and 48 x  48 x 1 pre-filter.  While its 22 yr old it has about 10 run years.

Good square-wave response is still a good go test even though it was removed from the 'Audio-Cyclopedia' in later edition.

Warren Shulz
WLS CGO

-----Original Message-----
  From: Dana Puopolo
Importance: Low

At 850 WHDH in Boston, I had a 317 C2 and an original MW-50, updated to a C.
Both were licensed as alternate mains. I much preferred the sound of the
Continental to the Harris on air, as did my boss, the GM.

We modified the Continental by replacing the input transformer with a
differential input. Boy did it like that! It modulated like crazy!

Later on I visited the site. The Continental was on the air, but absolutely
filthy inside. Later on it caught fire and they replaced it with a DX50.

-D