quick and dirty Mono Sum circuit

[cranberry]

Hi,

I'm hoping someone could point me in the correct direction for a suitable circuit to SUM a stereo line level signal to Mono.

I found the following circuit via google:

An externally hosted image should be here but it was not working when we last tested it.

Would this do the trick?

Thanks in advance

 

[cranberry]

bumpski - anyone?

thanks.

 

[Speedskater]

The output of device #1 will also be sending it signal to the output of device #2. Your units may be able to handle the higher load, but not all units can.

We have two 475 Ohm resistors in series (times 2), the output impedance impedance of devices #1 & #2 which may be well under 100 Ohm, the 20k resistor and the input impedance of the next unit to deal with.