Best preamp for McCormack amp

As a former McCormack amp owner (0.5 deluxe), I'd say you should think about mating it with a tube pre-amp. I first tried a passive and then an active SS pre-amp and felt the midrange was just too lean. Trying it with my friend's Quicksilver preamp showed me what I was missing in the midrange and I began seeking out tube preamps. Of all the preamps I tried, I liked the Audible Illusions 3 the best with the McCormack. YMMV of course, but I think tube preamp will get you the sound you want.

I will second Gileon's opinion. I used an Audible Illusions M3A preamp with McCormack amps for years. It is a very synergistic combination. If you don't plan on having a turntable at some point, then the L1(M3A without phono) is the ticket (you could still purchase an outboard phono at some point if desired.)
The AI preamps have been on everyones reviewed top list for years. Sonically, the AI pre's impart a touch of warmth to the mids which offsets the McCormack's slightly dry mids as mentioned by Gileon. Makes for a very, very musical prensentation.
I currently use the new Audible Illusions L-2 preamp with remote.
One caveat to tube preamps is you do have to replace tubes periodically and they can be problematic at times.
The McCormack TLC is very transparent but, depending on source components, may be insufficient for drive level. I would look more at the McCormack active preamps such as the RLD. Also, the TLC presents a slightly lean presentation and dynamics are not quite as good with the passive unit as compared to an active preamp.
Another very reasonable preamp is the Adcom GFP750. A Nelson Pass design that received a lot of glowing reviews. It is switchable from passive to active and also has a remote. It is very transparent(equal to the TLC) and may actually be the best preamp buy around at its current used priced.
They're many others but I do considered these three to be tops for the buck and I know work well with McCormack amps.

I doubt that you could find one in the used market, but if you can, get an Audio Prism Mantissa preamp. You could cough up the extra bucks and buy the same preamp from Red Rose (aka Mark Levinson) - he bought the Audio Prism tube line.

If not, then try to find the best tube preamp that sounds as transparent as a passive. Not an easy task but worth the search. Most preamps cause a haze over the signal. The DNA amps will let all of "it" through and are awesome with transparent equipment in front of them.

Enjoy,
Bob

Thanks everyone for your responses. I've been on vacation so I apologize for not responding sooner. I'm hoping to get a used system in good shape, very possibly thru Audiogon again. And soon! My amp is lonely......