[BC] Re: 317 and MW-50

[Mike McCarthy]

WJJD did get their DX 50 in the mid-90's to replace the dying RCA.  It was 
Joe Wilk's last install project before succumbing to the devils associated 
with diabetes.

MM

At 10:25 PM 1/2/2006 -0500, Xmitters at aol.com wrote
>In a message dated 1/2/06 5:09:48 PM Central Standard Time,
>broadcast-request at radiolists.net writes:
>
><< That said, the 317 always sounded a little cleaner, but comparatively
>  less loud than the MW50, driven by the same chain.  I always assumed it
>  was slightly higher IMD and distortion from poor high freq. negative
>  carrier pinchoff in the 50 that contributed to the very slight apparent
>  loudness increase ('filling in the holes'). >>
>
>To be totally correct, the envelope, and not the carrier pinches off at the
>negative modulation trough. Vector sum of the carrier and the two 
>sidebands is
>zero at that instant.
>
>IMD was an issue with our 317C-3 as well. We usually had to swap PA tubes
>around and tune up again to see which tube worked the best in which 
>position. A
>good friend of mine can hear the difference between the 317 and MW50 with the
>317 sounding "warmer". I often wondered what the PA screen audio coupling
>transformer did to performance regarding overshoots and distortion from 
>the iron in
>general. There was a nice audio feedback loop that worked very well that
>probably killed most of it, but I often wondered what exactly that 
>transformer was
>doing to the audio and the effect on loudness. At the time I was in Chicago,
>of the 50 kW stations almost everyone was using the 317 so engineering got
>little pressure from programming about loudness. I think WJJD had their DX-50
>sometime in the mid 90's when I was in that market. anyone remember?
>
>Jeff Glass, BSEE CSRE
>Chief Engineer
>WNIU WNIJ
>
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