Audible Humming Noise! Not Sure Why

[xllund]

Hello All,
I am new to this site, and I hope that I have posted this problem on the correct forum.

SETUP> Yamaha YPG-635 keyboard, using headphone jack as output, it is then split to L & R plugs entering a Boss RT-20 pedal. Stereo inputs used, and stereo outputs used. From the pedal, L & R ouptut leads feed into a Lexicon Alpha mixer. Stereo in, and stereo out to studio monitors.

PROBLEM> When connected as described above, I am getting a low volume humming noise during recording (Cubase LE-4 software.) It reminds me of amplifier noise, such that you would experience when you unplug a guitar with the amp volume raised.

When I bypass the mixer and go straight into the studio monitors from the RT-20, no problem at all. Do I need to get some sort of filter? I am stumped, and any help would be greatly appreciated. Thank you to all in advance.

Xllund

[mjbphotos]

Sounds like the mixer is amplifying the hum brought into the chain earlier - the keyboard's headphone output is the only option? No line out available?

[gecko zzed]

My inclination is to check the pedal. If that's running off a wallwart, you might like to try switching to batteries. Better still, don't use it.