The stereo/mono adapter simply "Y" connects the left and right from the source. You still only use one hot lead and the ground to connect to the KSU (the mono side of the adapter). A mono plug being used in a stereo headphone jack actually shorts out the right channel on the music source which is hard on the output transistors/ic.

The MOH is supposed to be an isolated input already on the KSU so no external transformer should be required. However, like "skwirl" stated earlier, I have also reversed the polarity on the input and found it to work better as well.

[This message has been edited by twisted pair (edited August 05, 2005).]