Pre-amp match for Moscode 600

Since you're running tubes (albeit, a hybrid), I'd suggest that you go with an all tube pre-amp. There are many to choose from, but you didn't mention a price range or if a used item would be considered. I'd look into Blue Circle, Melos, C-J, MFA, or even AI. You might want to check out www.Wright-Sound.com as well. The Moscode doesn't have have any unusual input demands, so any good quality pre-amp will work. Of course, your preferences will determine the "best" unit in your budget for your system. Good luck.

Some of the preamps from the day (or thereabouts) would be great matches IMO, especially with a possibly bright Thiel.

MFA Magus, Lazarus hybrid, one of the Audio Research earlier models, or the Moscode preamp (wa sit called Minuet-In-A ?), etc etc

Lots of luck, whatever you do.

Your amp probably has a high (>50k ohms) input impedance; my tube amps do. I'm going to be a contrarian and suggest you run a passive or SS preamp with your tube amp. I'd start with the Adcom 750. As a rule you find this a synergistic and quiet pairing.

I was using a an Audio research LS-2 with my modified Moscode 600. I then tried a Birdland Odeon Lite D/A converter with a volume control and it was an amazing improvement.

I have a fancy VAC preamp with my Stephen Sank-upgraded Moscode 600. It sounds sublime.

I would recommend looking into a used VAC Standard preamp; they come up from time to time on Audiogon.

Meanwhile, if you're interested in getting the most out of your Moscode, I'd get in touch with Stephen Sank and find out about the range of options he offers. Unlike others who work on Moscodes, Stephen does nothing significant to the original circuit design; he just upgrades everything with very high quality components. My amp came back sounding utterly transformed for the better; much *much* better in fact. He's at http://www.stephensank.com/