Preamp for magepan 3.7 and Sanders amp combo

I would highly recommend taking a look at Eastern Electric Avant. Yes, it's really that good.

I am currently using a Reference 3 that I bought from a fellow Audiogoner a year and a half ago. It sounds marvelous, especially since I went past the 300 hour barrier on the 3.7s. Things didn't really open up as soon as I thought they would but the wait has been worth it. I know you said the Refs were out of your price range but a used Ref 3 might be a possibility.

Good luck with the Maggies!

You might want to try a lector zoe (easy tube rolling). I used one with my magnepan 1.6 speakers and they added the correct missing tonality for many instruments. I believe you need tubes somewhere in your front end equipment. I'm sure other fine tube pre amps will also work well.