Chony,

Much of this depends on the keyboard. In some instances, the headphone out will produce a fair degree of high frequency hiss because of a slight impedience mismatch, but this is not always the case. Some of the less expensive Yamaha boards only had a single output, which could be used for headset or standard output, and they were equipped with a single, stereo (TSR) jack. I also know of a few Tyros users who claimed good results as well, but most were sending the signal through a mixer before going to a stereo amp. Give it a try and let your ears be the final judge.

Cheers,

Gary