need decent cheap pre amp to drive

bought pair of maggie 1.6qr speakers.have carver 500t amp and carver c1 pre.need a little more bass.what to do? want to spend under 750.00
If you want to save some real money and get one of the best used preamps available, check out the Adcom GFP565 which is listed right now on A-gon. I had a 565 for nearly 4 years, and can vouch that it's an excellent unit. If you have an analog front end, this preamp also has an excellent phono stage. The one I just saw listed is selling for $325.
Excellent suggestion (former owner). A friend also drives his McIntosh MC225/Quad ESL system with a GFP 565. Sounds great!
As a longtime Maggie user I can have come to the conclusion that the common complaint that "Maggies don't have enough bass" is many times more of a "Maggies with inexpensive solid state electronics don't have enough BODY" issue.

Maggies LOVE tubes. They are very tonally natural through the bass and midrange regions; perhaps even a bit too lean. As a result they benefit from the tonal body and fullness that tubes can inpart. While they will not give you the kind of potent bass that some box speakers will, I have found that their bass is natural and detailed like few others. In my experience if the sound is lean and dry through the midrange, as is usually the case when Maggies are driven with inexpensive solid state, no amount of bass will satisfy. Conversely if the midrange/lower midrange is adequately full and dimensional, as when driven with decent tubes, I can do without great bass extension and power.

My suggestion is to try a tube pre-amp and eventually a tube amp as well. In the 750.00 range I like and have seen for sale here: Audible Illusions M3, Quicksilver, and if you can find one, I love the Melos 222b or c. I don't know if you need a phono stage, but there is a EAR 834L Deluxe listed here for sale. Talk about beautifull, dimensional and full bodied sound!

Good luck and Happy Holidays.
A Golden Tube SEP-2 or SEP-3 pre will do nicely for a very reasonable cost, includes remote, & may even have an internal phono stage if so equipped. Tubes also provide the option of rolling in different tube-types in order to alter sonic signature.
However, your existing equipment may have more available than you initially realize? Experiment with different upgrade AC cords, interconnects, perhaps even speaker cables. Other tweaks such as "shelving-over-Vibrapods" can also work wonders at times so if you haven't experimented with tweaks etc. then it's well worth your time.
just want to thank everyone who responded to my inquiry.the tips are invaluable.the adcom pre 565 seems like a good idea