Inject Mono line into Stereo channels (EQ Bypass Circuit)

[chumingo]

I have a mono line that I want to "inject" into two separate channels, while naturally keeping both channels isolated. In the diagram I'm attempting to do this via two resistors between the mono line and the stereo channels. Would this be enough to avoid crossover between Left and Right?

I also don't know what mixer circuit to use at the mix point of the lines. I've read in favor of an opamp with virtual grounding but I'm not sure about it and I need to keep things simple (without detriment of sound quality/transparency and channel isolation).

Both stereo and mono lines pass through a parametric equaliser that can be bypassed via switches, as shown in the diagram, to feed in a sound recorder.

Any guidance will be hiiiighly appreciated!
Domingo

 

[mjf]

..........imho keep the output impedance of the mono out as low as possible
( 510ohms is too high ) to avoid "crossover speech"

 

[chumingo]

Thanks a lot for your help @mjf.

After reading and some research I came up with the following solution using opamps (in attachment).

The idea is first to equally sum the mono line into both stereo channels, then to bypass the EQ at taste using a pot. Would this work to avoid crosstalk, due to virtual earth, or I would still need to reduce the impedance of the mono line as suggested? Any comments on the bypass mixer will be much welcome as well.

Many thanks,
Domingo

 

[mjf]

Q.........
The idea is first to equally sum the mono line into both stereo channels.......

yes, this should work .
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suggestion: try out a panpot to bypass the equalizer as you like