Matrix mixer for parallel effects question

[BJM]

Hi all,

I've finished building a passive matrix mixer to use together with the ROG splitter/blender. I've changed the splitter/blender to 4 outputs instead of 2 so I have 4 parallel effect chains going into the mixer, the first two with a A/B switch and the two outputs going back into the blender. I've drawn a rough schematic. All the pots are 100K linear and 15K resistors (except the bicolor leds) found in a schematic of a "regular" matrix mixer. I'm not very good with the technical side so if anyone could take a look at it to see if these values are correct or if it can be improved (I have some volume loss..) that would be great.

Thanks,

Bert