Stereo to Mono Convertor - How to isolate?

I have built a stereo to mono converter.

I have used a 1/4 watt 5% 10kohm resistor between both the left and right stereo + sides as the signal goes to the mono connections.

Possible inputs are 1/8" stereo, 1/4" stereo (TRS), RCA stereo and 1/4" L/R Stereo.
Possible mono outputs are RCA and 1/4"

The converter does a very nice job of providing a mono line signal that I can send to a mono channel on my mixer.

I would like to isolate the signal so that it can only travel through the resistors to the mono connectors, but that the combined signal cannot travel back to the stereo inputs/outputs.

I do not have electronics knowledge, I have gotten this far from information that I found on the internet. I have read that diodes can accomplish this. Can anyone tell me if a diode (or other electronic component) could accomplish this for me? Size of component and other helpful instructions would be appreciated.

Thanks!
Scott

Tell us EXACTLY what you're trying to do, and what with, and not how you think it needs to be done - and certainly no diodes are required.

Stereo to Mono Converter - Use also as adapter

I have built a stereo to mono converter box

Stereo inputs are:
1/8" stereo
1/4" stereo (TRS)
1/4" L/R Stereo
RCA stereo

Mono outputs are:
1/4" mono
RCA mono

The diagram in my first post shows that I used a 1/4 watt 5% 10kohm resistor between both the left and right stereo + sides as the signal goes to the mono connections. The resistors are soldered together for the + side of the mono output. The converter functions well.

I would also like to use the box to adapt one stereo input to one of the other stereo jacks. (Ex: adapt Stereo 1/4" to RCA stereo.) How do I keep the summed left and right stereo + signals from traveling back to the stereo inputs?

I do not have electronics knowledge, I have gotten this far from information that I found on the internet.

Note: on the diagram I left out 1 label – the circle between the stereo rca jacks and the resistors represents a 1/8” stereo input.

Thank you.

You still don't provide enough information, such as exactly what are the source and destinations - but in almost every case there's no feedback to the source, two resistors are fine. For that matter, in most case just shorting them together is perfectly fine as well.