Can I make the volume louder by using a pre-amp?

Please offer any advice on whether I can make the output volume louder by inserting a phono pre-amp or SUT in my system. I just purchased a Rega RP6 to get back into the sound of vinyl. I currently have to crank up the volume to get decent output.
I have relatively old equipment. My current system is Denon AVR-3808CI receiver that I am using as a pre (phono is 2.5mV input sensitivity with 74dB S/N and 150mV rated output); Rega RP6 with Dynavector 10x5 cartridge (2.5mV output voltage); Parasound HCA-2205A amplifier (220W per channel @ 8 ohms); Paradigm Monitor 9 speakers.
I understand that the output voltage of the cartridge matches the input sensitivity of the receiver. Is this the best I can do, or does it make sense to increase the gain by using a pre or SUT? Do I have some other limiting factor in the equipment chain with the components I have?
Any input and/or suggestions is appreciated. Thank you. -Dan
Look to see what the input sensitivity of the Parasound is in order to get it to produce full output. If the Denon does not supply that the amp will not put out its full rated output...

Since you are using an AV receiver as your preamp, I am assuming you are outputting the front right and left to the amp?

If so, you'll need to go into the settings of the AVR and make sure those (2) channels are turned up. Usually these would be set by the microphone for use with the surround sound channels. Could be that these are turned down a bit to match the other surround channels.
The picture I found here does not show a phono input, only line level. In other words, there is no phono stage to provide the equalization and gain needed to drive a line level input properly. So yes, the short answer is you need a phono stage. An SUT will provide additional gain but will not provide the required equalization, so an SUT is not the answer.
Swamp...there is indeed a phone input on this AVR. It even
has the ground terminal right next to it. Look at the
picture you linked again.

It's just left of the AC input for the power cable.

See page 38 in the owners manual. There is an adjustment for "Source Level". Hopefully this will allow you to increase the phono input without affecting the level of the other inputs. Appears that it will increase the gain up to 12db.
Are you certain the phono pre is operating aside from just being an existing input? Are there other selections that must be made, as Tls49 has pointed out?
Well I'll be hornswaggled! The inputs are in 2 separate banks. Never seen
that before! My bad.
Mofimadness, Tls49 & Mechans - thank you for the comments. I will go into the receiver setup and see if I can make those adjustments.
If the input sensitivity of the receiver is 2.5 and the output of the Dyna MC is 2.5 is there any advantage to boosting the signal between the turntable and the receiver with a preamp? Would that help at all? Is that possible?
Sorry if it is a silly question, but I don't have any experience with phono preamps and higher end phono equipment. The Rega is the first real upper end purchase I have made in the phono realm. Looking forward to finally making my old vinyl sing, and just want to make sure I am not limiting the potential with an incorrect setup, or something needed to assist my existing components limitations. Thank you.
Sensitivity is the lowest value that the phono input will amplify correctly. Since the cartridge also has an output of 2.5mV, that is the lowest value that will work correctly. You would have been better off with a higher output phono cartridge. The way it is now, you don't have a lot of options. A SUT will not help since you only need a step up of 1:2 or 1:3. Any more than that will overload your phono stage. I don't believe there are any SUTs in that range. questions are silly. You should always ask, if you don't know/understand something, than going ahead a messing things up.

First off...your AVR3808CI should be fine to use with your RP6, once we figure out the volume/gain issue. can't really use a SUT, (or a pre-preamp) into your existing phono input because you will overload the input and cause some nasty distortion. SUT's are designed to boast a low output moving coil cartridge, (usually .3mv or lower). Your Dyna is 2.5mv, (considered a high output moving coil), so a SUT would majorly overload what you have now.

You could always buy a separate phono stage. These run into an existing high level input, (anything EXCEPT the phono input). An outboard phono stage, depending on make and model and price, could be a major step up in performance. There are many to chose from.

Bottom line is, your receiver should be fine. You can always get better sound if you want to spend the money.