On Sun, Feb 23, 2025 at 06:01 PM, Casey wrote:
I believe the the audio interface is providing a stereo 1/8" jack, but it mixes to mono internally
It is not stereo, it is standard PC microphone wiring of a TRS jack, sleeve is shield + signal and power return, tip is signal, and ring provided power for a capsule with built-in FET.
The Amazon page you linked shows pretty clearly that a TS jack is not supported, so I would think that a TRS jack with both wires connected together at either end would be electrically equivalent, and would also not work.
However, most of the information I could find about PC standard microphone connections indicated that both the resistor and the DC-blocking capacitor are typically in the audio interface, in which case I don't see why connecting tip and ring together at any point would not work.
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The microphone input likely meets the old PC2001 connector requirements:
If the PC has an analog microphone input, it must meet the following
specifications:
? Three-conductor 1/8-inch (3.5 millimeters) tip/ring/sleeve microphone jack
where the microphone signal is on the tip, bias is on the ring, and the sleeve is
grounded.
This design is optimized for electret microphones with three-conductor plugs,
but will also support dynamic microphones with two-conductor plugs, where
the ring and sleeve are shorted together.
? Minimum AC input impedance between tip and ground: minimum, 4 kilohms.
? Input voltages of 10–100 millivolts (mV) must deliver full-scale digital input,
using software-programmable gain.
? Maximum 5.5 V with no load, minimum 2.0 V with 0.8 milliampere (mA)
load, direct current bias for electret microphones.
? Minimum bias impedance between bias voltage source and ring: 2 kilohms.
? AC coupled tip.
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If that is the case then indeed you should be able to connect tip and ring together, which wires to the drain terminal of the on-capsule JFET (term 1), and the sleeve connection to the term 2 ground connection of the capsule.
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powered from that interface via PiP.
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I am not familiar with"PiP," does it match that connection described above?
Do you also have an electrostatic screen of some kind which surrounds the capsule?
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I see that there is another response which came in while I was typing which indicates that you did add better shielding using conductive tape.
When I connect ring to ground (which I think is what a mono plug will do, right?) the mic goes totally dead.
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Correct, you cannot use a TS plug, because that will short the bias power to ground, meaning no power to the electret capsule JFET.
You can use a TRS plug and short T and R together, but you cannot short T and S together.
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-- Chris Caudle
