My preamp gives a balanced TRS output instead of unbalanced stereo which is what my input device requires.

Is it possible there is a reverse DI box of sorts that converts balanced mono to unbalanced stereo (where both channels are the same) by flipping only the phase of the ring signal?

I've seen tons of examples of how to do this conversion w/ TS cables, but my goal is to have it output 2 channels. Currently I'm taking one half of a balanced signal and then using a Y-connector to make it stereo. This effectively halves the signal again for each channel. That's a fourth of the total original output.

  • 1
    "This effectively halves the signal again for each channel." -- No, it doesn't. Unless you have a ridiculously low input impedance, the preamp basically acts as a voltage source. Apr 27, 2015 at 22:30

2 Answers 2


If your preamp is mono there's no way to get a genuine stereo output. You can use a Y-split (TRS > 2x TS) but that's just two mono signals.

If you need a stereo input then, in your case, you need another mono pre. Then just send L and R inputs to a single preamp, and then take the outs of those into your input device.

  • You can use a Y-split, but not only will it only give two mono signals but two mono signals with opposite phase, which sounds really weird and pretty much kills the bass range. May 25, 2015 at 18:35

Two possibilities:

  • Use an “inverse DI”. Actually, passive DIs work both ways, so you can indeed plug the balanced signal with XLR into the DI's output, and grab off two unbalanced signals at the “input” and its parallel link. Works pretty well. I use that technique occasionally to convert balanced monitor lines into (mid-panned) stereo signals for headphone preamps. Depending on the DI, the output signal will be rather high-impedance though, and have a rather high voltage; careful to avoid clipping.

  • Use the balanced out as an unbalanced one1 (by plugging in a TS cable), and split that out in two lines. This does not lower the signal level in any way as Sebastian Reichelt commented; only it does lose you the benefits of the balanced connection, obviously.

1The correct way do that is to short one of the signal pins to ground2, not leave it unconnected! Hence the TS cable, which simply realises S and R as a common shaft. If you leaving the ring unconnected, the lower impedance of the used wire means pretty much all of the signal goes through the other one!

2Strictly speaking, this only works with a servo-balanced output. Which is pretty much the standard.

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