Dynavector DV20x2H cart for MM phono stage ?

What line stage are you currently using? Also, I agree with Ejlif. If you have $2500 to spend on a phono pre, it would make a lot of sense to go with a low output cart. I haven't heard the 17D but I have the low output version of your cart and its a very nice upgrade over the HO version.

I think he's talking about a full function with phono. The A21 an amplifier. There are a lot of great preamps out there available on the used market where you get a great amount for your money. ARC SP 16 or 17 is a great value used. You can often find a Joule LAP-100 for your budget. An Audible Illusions M3 series is a great starting place and that can be had for way less than your budget. Just be patient and wait for what you want to come up used. It will be well worth it. IMO those full function preamps outperform all those low cost solid state external phono stages like the NOVA or JC3 or PS Audio, etc.

Dhcod: Thanks. Yes, I am talking about a full function preamp with phono ...

If you do decide to go with a separate phono stage all you need for really great sound from a Dynevector 20X H is an MM level of gain.
I own one and use a Graham Amp 2 SE, and think it sounds fantastic. It is a dedicated MM stage but works really well with my HO MC cartridge. I wonder how much better the low output version could be given my satisfaction with my current albeit modest analog rig. It is just a VPI Scout with the regular JMW 9 arm and normal platter.

Since the A21 amp has balanced inputs, you may look for a used AtmaSphere MP-3 linestage with optional phono stage. They occasionally show up for sale at your budget and are quite good.