I have a guitar amp that has a headphone output.

I would like to convert this signal to line level so I can use it in a small mixer along with other line level signals to be heard in "in ear" style headphones for a live monitoring setup.

How do I convert headphone level to line level?

(And line level in this case is assumed to be the "consumer" line level, aka "-10db" line level)

Also, I would need to convert the stereo output of the headphones into a mono signal in a reasonable way. I'm happy to just discard the right channel since the guitar amp is mono anyway, but I would be curious to see if there is a way to sum the outputs, for example, for the sake of learning, let's assume that left and right outputs are different signals here.

I'm guessing the solution is relatively simple, likely just a resistor or two.

  • \$\begingroup\$ it's easy, once you can spec the headphone level in dB \$\endgroup\$ – Tony Stewart EE75 Mar 11 '19 at 2:36
  • \$\begingroup\$ An L-pad would work! And sure, it is entirely possible to sum the left and right headphone signal..but why? \$\endgroup\$ – user156429 Mar 11 '19 at 3:02

We have to assume what your Headphone output is.

If output is 5Vpp is being reduced to 1Vpp (-9dB Vrms) to a 10kohm line input, it needs 3 resistors to make a mono L-Pad.

2k2 (left) +2k2(right) to 800R to ground or 1k Audio pot.


simulate this circuit – Schematic created using CircuitLab


Couple of resistors, or a trim-pot even, to reduce the signal level as needed.


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