impedance problem?

[BigPapaFly]

impedance? Actually, I really don't know what that means...but here's the deal. I have a very skeletal set-up...a laptop running Cakewalk to a midi keyboard, which generates all my tones (the keyboard does, that is)...and the keyboard going out to a TASCAM 788. I monitor the 788 through a home stereo by running out of the TASCAM into the AUX ins on the stereo unit. It works, BUT, I get nasty buzzing through my speakers. The buzzing is only there when the cable from the keyboard is plugged into the TASCAM, so its not a problem with the TASCAM alone. I've had some problem with the OUT on the keyboard, having to jiggle it and whatnot, but when the midi chords are disconnected from the keyboard, and only the connection between the keyboard and the TASCAM remain, the buzzing stops. So, I bought a new power strip and plugged everything into the same strip- laptop, keyboard, laptop speakers, tascam, even the cdr attatched to the keyboard is running through the same power strip now...

Any ideas?

Thanks for any help.