Forget the GFP-750! It's not Class A, never was, never will be. Sold it at 3 audio/video stores over the years. It's not as good as many think.(maybe Class C...seriously). Infact every other preamp in the store at it's price or above was better...a sheer example that fuels the question from a post earlier that asked "is there any non-compensated reviewing anymore???"
Anyway, McCormmack's very own TLC is better by a lot over this piece, as is Pass Labs Aleph L for the same money used, or better than 750 Adcom.(can you tell I don't like it?..it's not so special IMO)
Other good pieces in Tube used are the stellar Cary linestage that retailed for about $1200 w/no remote. Can't remember model number.."LS50" or something like that.
The Audible Illusions pre's work best with tube amps. Used Audio Research pre's (LS2,5,7,15,etc) are good for $500-700 range with tube upgrades. Even the Audio Experience Symphonies tube line stage that "infintebaffle" recommended is something I'd try before pickig up an Adcom personally. Again, sold that line for years, along with McCormmack as well.
Another suggestion is a simple passive line stage from most any company(except...ehem!)
Dynamics will be better with active linestages however. I think the choices above should get you what you need for a few hundies. Good luck
