New preamp or up grade my cartridge and or phono amp?

Add on question. I understand that my AV preamp is a kind of jack of all trades unit what I don't really understand how a preamp would change anything if I'm using the reference mode on my AV preamp?

Preamps matter, and they matter a lot.  They are often called the heart of a system for a reason, so dismiss it at your own risk.  A good stereo preamp should significantly outperform your prepro in any mode and would probably be the first thing I’d add/upgrade in your system.  Just my $0.02 FWIW.

@soix

+1

Given your current selection, I would start with a good quality preamp, then move to a better phonostage.

It depends on where you want to go, how far? You are in the process of "evolving" your system. The only wear item is the cartridge. You have to replace them once in a while. If your goal is to build a reference system then make big steps when you can afford them. Do not waste money on little steps if they are not at the final level you wish to achieve. I would do turntable, tonearm and cartridge as a package. If you are short money compromise on the cartridge as that will need replacing in the future anyway. A good table and Arm will last many decades. In your situation I would not buy a preamp. I would get a phono stage at the quality of your final system and plug that into your Emotiva. Equipment that represents the highest value would be the Channel D Lino C phono stage, the Sota Sapphire Turntable, The Kuzma 4 Point 9 tonearm and the Soundsmith Sussurro Gold cartridge. 

I’m not a Rega fan but my one cent contribution would be that it’s the Emotiva that is holding your system back.  Junk that, get a proper set of separates, and then scrap the Rega stuff when funds allow