"Evelick":
You got to be kidding me?????
A used ADCOM GFP-750?!?!?!?!?!!!!
For $1,600.00 ?!?!?!?!?!?????
I've bought mine brand new for about $1,400.00 almost a decade ago. Surely, you should be able to snap up a used one for about $600.00 to $850.00. The Adcom GFP-750 is a VERY NICE Stereo Preamp with a Home Theater Bypass (should you ever need to have that capability).
If there is otherwise nothing wrong with your Anthem AVM-2 other than the lack of D/P-LII and HDMI connectivity, and you have been satisfied with its performance and sound quality in the past, then I would just go ahead and hold on to it and get a used high-end stereo preamp such as the Adcom that I've just mentioned.
And then afterwards, you can just get a decent Phono Stage for just a few hundred dollars (one of the used Creeks should do it for you, unless of course, your ears and tastes are more jaded for than what a used Creek can provide for you).
Just my $.02 worth.......
--Charles--