Hector Martin

However, it has an undocumented analog mode, which uses the SuperSpeed pins on a USB 3.0 Type A connector (even though this isn't 3.0) for analog audio and status, to work with some Behringer mixers. So I broke it out to minijack stereo (two mics, two channels).

These the ULM200's? I was looking at those for a thing, and had no idea analog output was possible for them; might make them perfect for what I need.

Yup. The fact that they have analog output is documented ("Ultra-compact USB receiver with dual mode analog/digital audio interface"), but not how it works. It's intended for their mixers with a dedicated port for this.

Yeah, I’d seen that and assumed it was a weird negotiated thing; didn’t think about them using SS pins like that. If it’s as simple as cutting D+/- and wiring extras to a cable, I can happily hack that together. Is sound quality decent on them? Standard dynamic fare, I take it?

Yeah, bit of background hiss but nothing major. The range is pretty limited and they're 2.4GHz so don't expect great performance if the spectrum is crowded, but they're digital so when they work they sound great (and loss of signal doesn't pop).

One SS pair (I didn't pay attention to which) has the two channels (in connection order, the two mics are dynamically allocated to a channel). The other pair has RST in (active low) & status (active high = at least one mic is connected).

Probably wouldn’t even need the status pin for my application, so long as an inactive (d/c or off) channel is quiet; somewhat surprised “status” doesn’t indicate which channel(s) are connected. Thanks for the info, may end up picking those up if the need arises.