I thought that it was mentioned above but cannot find it now (perhaps I am thinking of another thread) but Musical Fidelity used to make a little add on called the X-Tone that you should be able to use as Bruce mentions using the Adcom in his above post and it could then be either switched in or out. The problem though is finding one on the used market, though it should cost $150 or less. I have seen three of them for sale within the last six months at Audiogon, Audo Reveiw and Ebay.
To tone control or not to tone control
I recently stepped up to a Conrad Johnson PFR preamp to mate with my CJ MF-2200 amp (200 wpc). Was previously running an Adcom GTP-450 pre/tuner which had bass/treble controls which help to compensate for those recordings which are recorded poorly. Though the CJ PFR sounds really good on most of my cd's there are some of my favorite artists whose recordings are really pitiful. Is there a good tone control which I can use on the PFR to use for these poor recordings? Is there a way to connect both preamps to one system. I do have an older cdp that I could connect to the Adcom preamp for the poor cd's and use the main system for the good stuff. I have also thought of trying a subwoofer to help with filling in the bottom end since most of the poor recordings are R&B and Rock N'Roll and that is where they seem to be lacking the most. The rest of my system consists of a Sherwood Newcastle 980 cdp and Infinity RS 5000 speakers (12 yrs old) and next to be replaced. As always your help is appreciated