Thanks, James!

I figured out my problem when I plugged a headset into the Korg. The Korg plays fine through headphones, so I figured that I must have been using an inferior cable to send the signal into the stereo.

I needed to pony up and buy some "real" cables for both of my keyboards. I was using a stereo headphone "extension" cable. It worked fine for the Roland, but I suppose it could have always been "borderline," and I may not have known it.

I've since made a change, and now I send the signals via separate left/right 1/4" mono-to-RCA cables into an old radio shack mixer that was just collecting dust.

The mixer has a fader that allows me to easily adjust the line level for either keyboard. I'm using a standard RCA patch cable to direct the signal from the mixer into the "aux" input on my stereo.

It took a little bit of adjusting, and requires me to constantly be aware of my levels in order to minimize distortion, but it's working okay for now as my "daily driver" setup.

Thanks for your time!

-- Brian