XLR to TS grounding/shock concerns

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FAP
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Re: XLR to TS grounding/shock concerns

Post by FAP »

crochambeau wrote: Wed Nov 23, 2022 7:39 am Do you measure +48V at both locations there?
Yes.
Illustrations would help.


EDIT: On a hunch, I browsed through the comments on the video I got the initial schematic from, and it turns out the guy wasn’t even using the center tap at all in the final build. Will elaborate & post my findings later.
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Re: XLR to TS grounding/shock concerns

Post by crochambeau »

og_circuit-colorized.jpeg
Viewed 74 times
Red is phantom power provided at mixer.
Orange is post switch phantom power, I asked you to measure that in reference to ground at each of the orange circles at the TX. Sounds like you measure 48V DC at those points, and not at the yellow circle point - correct? That would indeed indicate a failed condition at the transformer.

You can probably just fly the 6K8 resistor over to one of the orange legs to grab the DC supply for capsule.

If that creates a measurable DC voltage difference measured between the two orange circles, it would be advisable to add another 6K8 to the other leg and then connect them together where they feed the capsule, otherwise you might run into distortion.

Don't orient a polarized capacitor with the - leg facing a + voltage, especially at these increasing voltages - they tend to turn into resistors or in the case of tantalum violently explode, thus rendering your creation in need of even more time and energy.
When in doubt, add resistance.

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Re: XLR to TS grounding/shock concerns

Post by crochambeau »

If your center tap is open/disconnected on the TX it's just an annoying lack of DC supply you're dealing with, if the winding is open it will pass no sound.

I would place the rotary switch at the green region on the "high" side of the transformer winding connected to the microphone element, that way when it shunts to ground it is essentially bypassing the transformer unless there's a lot of resistance in the old works.

That'll be $50.

:lol:
.
When in doubt, add resistance.

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Re: XLR to TS grounding/shock concerns

Post by FAP »

That or I’ll eventually send you a completed build..?

Anyways, yep, it all works now! Not sure how it’ll work out with combo jacks yet. Thanks a bunch!
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Re: XLR to TS grounding/shock concerns

Post by crochambeau »

FAP wrote: Wed Nov 23, 2022 4:38 pm That or I’ll eventually send you a completed build..?
I'm just ribbing ya dude. I've got the fool idea of releasing some of my designs in DIY raw circuit format, so all of this remote troubleshooting is just preparation for a possible future. So while I sound curmudgeonly at times I'm also fully capable of just ignoring this sort of thread - and at times do when my bandwidth is capped.

Everything offered on this format is free and clear, if I were working with you in a professional capacity I assure you we would be communicating on a different platform.

Anyway, congrats on the progress!
When in doubt, add resistance.

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