NESRGB audio input/outputs mixed with Twin Famicom audio

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NESRGB audio input/outputs mixed with Twin Famicom audio
by on (#229419)
Tims NESRGB board does a really nice job. It also does a nice job improving the audio out by means of the O, A and B pads on the NESRGB PCB.
I have just dug out my TwinFC and RGB modded with a NESRGB board - but I thought, I would like to use the improved audio mixing circuit on the NESRGB, but also be able to utilize expanded FDS audio and other cartridge audio.

There is a through hole pad on the NESRGB, right next to J5 which you can use to inject FDS or cart audio.

Has anyone done this before ? Used the NESRGB's audio circuit and mixed this with the audio system on the Twin Famicom ? I think it would sound better than stock :)

Im not entirely sure where I could pinch JUST the FDS/Cart audio from, to then solder a wire between that point and the aforementioned injection pad on the NESRGB.

Thanks for any advice / ideas.