Elsewhere at AC is a thread that is discussing similar issues.
There I recently suggested that a stand alone stereo tube output stage with adjustable output level may be the answer. It would become a cathode follower when added to any line level source. Installed between player/DAC and the Clari-T it would take care of any impedance mismatches and replace the Clari-T volume control. For $400 (plus two more sets of interconnects) Decware has just such a beast:
musical fidelity came out w/a tubed buffer stage years ago, the x10-d. one f/s on agon right now.http://cls.audiogon.com/cgi-bin/cls.pl?preatube&1120685615
i have never tried one, but a friend of mine got one to use w/his sirius digital radio. now, at least, it's ok for background music, where before, it would give me a headache after thirty minutes or so... (no negative reflection on the x10-d - digital radio SUCKS!) at the same time the x10-d came out, a small company released the ase z-man tubed buffer stage. this unit was actually reviewed:http://www.soundstage.com/greg12.htm
i have two of these that i think are great for tunas & cdp's. i did a coupla easy mods on them & installed good nos tubes, which helped quite a bit. (i have not tried one on digital, since i started using my modded art di/o a while back; i have recently thought about giving one of 'em a go here...) supposedly the z-man is more neutral than the x10-d, but as i said, i've never tried the m-f unit in my system. and, m-f now has a new tube buffer stage - the x-10v3http://www.musicalfidelity.com/mf/en/Products/SmallX/SX10V3
and, kailin audio also makes one, the mu-1 - i bought on new on an a-gon auction for ~$180 shipped, from the usa distributor. it also works well. i have yet to a-b it w/my z-man, tho. also, i am awaiting some nos tubes for it to replace the junk chinese tubes that came w/it. perhaps it will sound even better then... there's one on ebay now:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3280&item=5772715539
it's kinda cool looking, imo:
none of these units have a wolume pot, tho... preamp is needed, or wolume pot on the source.
i have also found the z-man to be a worthwhile improvement between solid state preamp and solid-state amp...