Le 25/02/2025 à 19:16, Casey via
groups.io a écrit?:
It's a
two-wire capsule () -- AFAIK the ground
terminal is connected to the capsule body in that capsule.
I have continuity between capsule body and plug sleeve. It
just seems like the connection between the cable and the
capsule (maybe 5 or 6mm) where the wires are exposed is
enough to admit hum?
Not in normal circumstances. Are you sure that the body in
which you put the capsule is properly grounded?
No: there is no body -- well, no metal body; it's inside a
bakelite antique wall-mounted telephone mouthpiece. I was
under the impression that a 2-wire PiP capsule acts as its
own shield so I didn't need shielding, but apparently I'm
wrong and the join from cable to capsule does need to be
shielded?
Yes indeed.
Got it, thanks for the education.
There is a splice near the capsule, now shielded, and a splice
near the plug which is not shielded. The second splice does not
cause hum -- is that because it is further from the capsule?
I don't think so. It looks like there's more EMI/RFI near the
capsule. Why, IDK. It depends on too many factors. Or perhaps the
splice near the capsule is more exposd than the other.
-c
