Hi, I have a Modx6 and my understanding is that the output is unbalanced. Is it ok to use current balanced cables and balanced input on a studio monitor? Or should I usb out to my pc then balanced out of the pc to the the monitors? I don't really mix often. Mostly play to enjoy as a hobbyist. I really don't want the inconvenience of waiting for a pc to boot just to have better sound quality.
Connecting unbalanced equipment to balanced studio monitors generally depends. Refer to the monitor documentation. The Yamaha HS5/7/8 series has a 1/4" balanced female connector which accepts either 1/4" TRS (balanced) or 1/4" TS (unbalanced) connections. There is a picture showing an unbalanced keyboard connection and also documentation that TS cables are fine.
https://usa.yamaha.com/files/download/other_assets/4/793644/hs8i_en_om_b0.pdf
This may not agree with your studio monitors. I'm not sure what you're using and there are certainly ways to design incompatibility in.
MODX is indeed unbalanced using "standard phone jacks" interfacing to 1/4" TS cables.
I would not recommend using balanced cables. You'll likely have more luck using unbalanced (TS) cables connected to your studio monitors. Monitors, like documented in the HS series, should generally be compatible with unbalanced cables. Check your documentation.
Current Yamaha Synthesizers: Montage Classic 7, Motif XF6, S90XS, MO6, EX5R
Since the modx has a built in audio interface you can just plug the usb to a pc and plug your studio monitors to the modx. Then the usb audio passes through the keyboard to the monitors. Yamaha said a balanced cable will work fine on an unbalanced connection.