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/
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/