[Amps] World's worst coax connectors

[Jim Brown]

On 4/20/2023 8:30 PM, Jim Brown wrote:
> hat's something I've never experienced, and I did a LOT of work in 
> downtown Chicago!

Couple more thoughts. Many years ago, running Jazz Fest, I had a lot of 
AKG condensers, including a version of the C414 that had Pin One 
problems. This was '80, long before that was known. I killed RF pickup 
by coiling the mic cable around the boom stand.

With respect to mating connectors -- Neil Muncy did a demonstration in 
his EMC talks where he ran maybe 10 XLR cables (probably the big Belden 
braid shielded) around the workshop site connecting a mic to a mixer. He 
ran a big tape eraser along the cable; the magnetic field coupled only 
where the pair was untwisted through the connectors, demonstrating the 
importance of shielding.

At another workshop that Bill, another engineer, and I did in 2005, we 
fed two condenser mics with fairly long runs of cable to a Mackie mixer, 
one using that big Belden braid, the other using a good Belden CAT5/6 
with molded pairs, with one pair carrying audio, both conductors of 
another pair connecting the Pin 1s. I used a Kenwood TH-F6A, 
continuously keying the talkie to produce square wave pulses as I moved 
it along both cables to find hot spots, on 2M, 220, and 440. Both cables 
provided pretty decent (but not perfect) immunity, and neither was 
better than the other. The mic had some susceptibility, and the Mackie 
had a lot, but I didn't get close to it with the talkie. :)

73, Jim K9YC