Help me breadboard a phantom powered LED meter

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Well-known member
Jul 19, 2011
A wee lil project for someone familiar with the pitfalls of phantom power and what can and can't be done with it.
Was going to tackle this myself as a learning experience, but too many other things going.

Only a wee budget, but I imagine this would be a very quick and easy job for the right person.

Basically, I have a bunch of custom passive DI's I've built for my band etc.

I want them to show when there is signal present via LEDs. Could be a bar graph, or series of small LEDs, whatever really.
But it needs to be powered by phantom, not battery, and it needs to be buffered from the audio signal so the audio remains unaltered.

To be clear, I've breadboarded up various designs of meter using comparators etc. I don't really need help with the meter side, there's plenty of info around for meters.
The tricky part would be designing the circuit including ultra low power LEDs, low power opamps for the driver/buffer, comparators whatever to work with a power reservoir coming entirely from phantom which is sub 10ma.

Instead of asking for tips and help in the other forums, I feel like this is worth something in the order of a nice bottle'o whisky for someone who's done something like this before.

I dont need board design, just a circuit schematic I can mess around with.

PM if you can help me out.