Notice how i swapped L/R channels by reversing the cable on the MPU side! My SCB-55 is v1 and L/R are swapped so this is my fix!

Great! I pretty like so wonderful founds and always looked out them by myself. If you're interesting see my topic about pure low-noise sound mixer for DOS on EMU10k cards. Everyone can use it and mix up to 5 stereo channels (minimum). For example you can connect your MCP-2 cable to MPU Clone card and to AUX IN on EMU10k card. You shouldn't pull out the contacts, just connect 😀 (or reverse L/R for SCB-55). On the other hand you can connect SB16 LINE OUT to EMU10k LINE IN via jack-jack cable. And third - CDROM dig out to CD SPDIF IN via 2-pin cable and get best sound quality from EMU10k's LINE OUT or SPDIF OUT. And - you'll still have some free inputs: CD IN (analog), SPDIF IN1, TAD IN (mono).

Thanks for making this post Burrito78! Should help with internal connections! 😊

I will take this chance to repeat here as well that this helped discover a small bug that affects ~10 cards that I built: when you don't connect anything on the stereo jack the output gets grounded which is good and fine BUT it also means the AUX port also gets grounded. The solution is to:
- either contact me if you are affected to get this fixed
- fix the issue by disconnecting the 2 ground pins on L+R lines at the output jack
- insert a dummy jack at the stereo jack so AUX will work

It completely slipped my mind since the AUX port was added afterwards and all my testing was done with a pair of speakers directly connected to the mpu. Still it was a mistake. Needless to say that this is fixed after this was reported but like I said ~10 cards have this quirk (cards sold by Marmes these last 2 weeks for example are fine) - so anyone affected get in touch! thanks!