Ron,
Slightly off topic, but do the outputs remain on when the headphones are jacked into the D-100 or do the speakers go silent?
On my C-32 I always have headphones jacked in and frequently use them when fine tuning the MR-78, or verifying the sound coming out of the speakers aka the incoming signal really does sound that bad or the band really is terrible etc......
In response to a different post, on all of my sources that have volume controls, I tend to use them to level the inputs going into my C-32, otherwise some saturate or overload the inputs on the Eq I am using, assuming that feeding more than 100% of metered capacity into the Eq is a bad thing....