An old post, but I wanted to reply to phillyb and his comment about turning down he headphone gain on the SA10. I gave that a try and the sound really did benefit. As if some noise had been filtered out. Going through the manual, Marantz actually suggests turning the headphone output off for best sound. Page 26.
"The headphones circuit operation can be stopped to minimize noise from the headphones circuit which could interfere with the analog audio output signal."
Thanks for catching that.