To the OP. Sterophile reviewed what appears to be your speakers, here:
stereophile.com/content/proac-response-4-loudspeaker-measurements
(I deleted the www prefix in case the link is deleted.)
If this is your speaker and you plan on keeping the Proacs, JA noted a couple of points that should be kept in mind. First, the Proacs are not very sensitive. JA measured the Proacs' sensitivity to be 85.5db, which is not high. That would suggest you will need power to get the best results from your speakers.
Notably, I checked the ARCDB website and looked up the specs on your VT-200. Your current amp has a rated power output of 200 watts per channel and power supply energy storage of 674 joules, all of which permits the inference that you have a pretty hefty amp.
Second, the Proacs' impedance curve is pretty rocky. JA comments that a high output impedance tube amp would add sonic coloration to the speakers' frequency response. The ARCDB website reports that your VT-200 has a low'ish output impedance of less than 1 ohm (damping factor is 11).
Although I am a fan of ARC products, if you are trying to keep costs down, you might find that you are biased (pun intended) to look for a quality solid state amp that has a lot of rated power. There are many fine brands on the market and I'll let other members make specific recommendations.
That said, if you are inclined to stick with a low'ish impedance tube amp with umppff, in general, and another ARC amp in particular, you may want to consider the Ref 150 SE. If too pricey, maybe a Ref 110 if you see one pop up. I own the Ref 150SE and it drives my speakers like a champ, but then again, my speakers have a rated sensitivity of 92db.
I have another suggestion. I think your VT-200 is a pretty good match for your Proacs for the reasons explained above. I appreciate your frustration with frequent repairs, but nobody knows an ARC amp like ARC. Why not call ARC and see if they can go over your amp from top to bottom. I am sure ARC could put your VT-200 back to original spec and augment its reliability factor, … if they still repair the VT-200. You should also ask ARC if your amp can run with KT-120 power tubes. That would make a big difference in SQ. I would also ask if you can have the MK II upgrade done.
In any case, I would be hesitant to drive your Proacs with much less power than what you have now in your VT-200.
Hope this helps.
BIF