These were used for headphone jack on the front panel, have no
connection to the main preamp.

On Sun, 20 Jul 2003 22:58:28 GMT, (BITCASTER1)
wrote:

The McIntosh C11 and C22 preamps have a single speaker connection on the back.
One from the amp's output & one to a single speaker. No impedence is given and
there is only 1 in and 1 out. What is this for and what does the preamp do with
the signal?