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.
Tube or SS?
The Accuphase P300 is an amplifier I thought? For those Vandersteen 2CEs I would say get a used McCormack DNA-1 or DNA-1 Deluxe. Sometimes they can be found here for about $800 or more but they will go fast at that price.
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.
I asked a similar question a few months back when I also had an adcom 545mkii. In my experience though, the adcom didn't sound muddy at all. It sounded a bit thin with not much low end. The mids and highs were okay. Maybe a bit analytical bordering bright. I think the McCormack may be the best for that money. I happened to go with a classe ca-150 because I found one locally and I have a classe pre-amp so I figured they should have good synergy. If you want, search the forums for "best used amp under 1k" and you'll see the list of recommendations I got :-)

My sentiments exactly! :)

Is that why Classical and Country sound like crap on my "Funk Firm" turntable and Rick James integrated?
Yes. And since Rick James played with Neil Young when they were Young Canadians, he was, in fact, integrated.
Mswobo, don't let the jokes discourage you. My advise, which will cost you very little:

-Don't change any major component yet. Sounds like you are relatively new to the audio hobby; this is a great opportunity to learn about some basics that will help you forever.

-What is your turntable sitting on? Isolate it as much as possible, and then try to put it on cones for good coupling and rigidity. That should tighten the bass.

-Don't laugh: take some bricks (lead bars are much better, but....) covered with cloth or tape if you care about looks, and place them on top of your amp and preamp (away from any cooling slots or fins). Place amp and preamp on metal cones as well.

-Make sure ALL your connections are clean and tight.

-Place speakers away from corners as much as possible.

-Experiment with VTA and VTF on your Rega. Positive VTA, and lower VTF could help a great deal.

-Take two aspirins and call us in a few days.

Good luck.
I second the MacCormack if you can find it for your budget. I would also seriously consider the Adcom 5802. It is a major step up from the 545 so it could possibly address all your issues you have with your current amp.

That said, I'll echo what Frogman said as well and add the same comment as Plato with regard to room acoustics.

I doubt that your amp is the problem. Vandy 2s sound a little blah by design, but it's more likely that your room and seating position is the real problem. Do yourself a favor and get an SPL meter, a bass frequency disc and measure your room.
typical bass of vandys