Thanks guys. To answer,

Yes the SC uses a separate PS with two prongs so no help there.

When I finally got down to the final test, all I had to do with the audio cable is simply connect one end to either the audio in or out with the other end not connected to anything.

I haven't tried connecting the midi cables because trying to use the SC for audio recording using my keyboard I have to use USB, that's how the audio gets into the computer and into RB. I'm recording audio at this time, not midi.

I haven't tested the position of the three way switch on the combo input jack because I get the same noise by plugging into either of the audio outputs anyway. Again, this is plugging in with one end of a cable with the other end just sitting on the desk not plugged into anything.

I don't want to put anything in the audio path because it could color the sound and like all of us I want a pristine clean recording but if you guys think a transformer would be completely transparent I'll give one a try.

I haven't done much home recording for the last year and when I did I was using my EMU 1820M which since died so no I didn't notice any noise. I'm primarily an audio guy so I wasn't using the SC for that, I was just using it as a midi module for Biab and now that I'm writing this I didn't notice any noise using it via midi.

Bob

Biab/RB latest build, Win 11 Pro, Ryzen 5 5600 G, 512 Gig SSD, 16 Gigs Ram, Steinberg UR22 MkII, Roland Sonic Cell, Kurzweil PC3, Hammond SK1, Korg PA3XPro, Garritan JABB, Hypercanvas, Sampletank 3, more.