Hi Justin- You stated that your receiver does not have a phono input and that your pre-amp must be turned up to nearly full volume. We still need to know more information to helop you. How are you connecting the pre-amp output to your receiver, does your pre-amp have a phono input, and if so, is it identified as MM or MC. Finally, what kind of cartridge is in your turntable? If you don't know the answers, tell us what the make and models are and we can probably figure it out.
Right now there are several possible problems.
1. Your pre-amp may also lack a phono input. The output from a phono cartridge is much lower than the output from a CD, DVD, video game player (which can go to any non-phono input on a pre, integrated, or receiver). The phono cart output needs additional amplification and must also be equalized (tonally adjusted) to compensate for physical limitations of the LP medium. If this is the problem, you either need a stand alone phono stage or an integrated or receiver that has a phono stage built in. Pretty hard to find a current receiver that has one these days. Some integrated amps do; and some pre-amps do.
2. If your pre-amp has a phono stage, it may not have enough gain for the cartridge. Some cartridges (mostly moving coil types) have outputs in the 0.02- 1 millivolt range, which is not enough to drive a typical phono stage and require a step up device of some kind. More "conventional" cartridges as called moving magnet (MM) and have an output typically in the 2-5 mv range, and can drive a typical (or MM) phono stage adequately w/o a step-up.
If either your pre-amp lacks a phono stage or your cart is a lower output MC design and your pre-amps phono stage is designed (or switched) for an MM design, you will get very low volume. If #1 is true, you will also get a signal that requires tonal adjustment.
I assume that you are taking the output of your pre-amp and feeding it into one of the inputs of your receiver. If so, once you get a proper phono stage, you would want to feed that into the pre-amp in input on your receiver, if it has one. If not, then you would need either a separate power amp, or a different receiver w a pre-amp level input.