need an amp...

I have put together some components;

Rega RP1
Accuphase P300 preamp
Vandersteen 2CE's need cables for them also.

powering it with an Adcom 545II and need definition in the bottom end and sounds muddy to me.

budget is up to 800.00

I listen to a lot classic rock late 60's to mid 70's, some jazz and Blues.
Be careful to avoid an amp that DOESN'T work with classic rock from the LATE 70's...or only works with blues...I had an amp that worked with blues but when a passing chord, modulation, or more complex song structure occured it was LIGHTS OUT. I hate that. An amp that plays music from 1975 but balks at 1978 can be limiting but clearly period appropriate. As long as you use an amp for "some jazz" and don't put too much jazz through it it can work fine, but be warned...I played a bunch of jazz one day through my classical music amp and my cat caught fire. Sad...but hey, you can't be too careful. You really need several amps for different musical genres, and trying to dodge that fact can only lead to trouble. Play Dubstep on a Mumblecore amp? No way man...
Two things: The Vandersteen 2CE is likely not the best at bass articulation and secondly, your muddy bass problem could be largely due to the acoustic properties of your room or the speaker's placement within your room.
In my opinion, the Musical Fidelity A3, A300, A3.2 amps are very good all around performers for the money. That said, they are better in midrange and high end than in the bass, which is tight, but not pronounced. Of course this is all my humble opinion.

Good luck.

Is that why Classical and Country sound like crap on my "Funk Firm" turntable and Rick James integrated?