Best monoblocks around 3-4k used for revel studios

you may peak onto audioclassics.com and find Melos 400W monos within your budget.
they're realy great.

I would definately look into the sonic frontiers power 3 (regular or SE) model. I love their stuff.

Jungson JA-50 pure class A momoblocks rated at 80 watts rms are a steal at $2500 a pair from sekei.com. They will drive your studios with ease. I have a pair driving VSA VR5 HSE and they are as close to a tube amp in ss that I have heard.
Built like a tank.

Have seen Rowland model 7's listed in that price range. Great sounding and beautiful to look at.

I have Salons, as does a close friend of mine, so I think our experiences will be valuable with regard to the very similar Studios.

The Power 3's do sound excellent with Salons. My friend ran this combo for a little over a year. Kal Rubinson of Stereophile runs Power 3's with Studios as his reference.

I also ran Rowland Model 6 monoblocks on my Salons for a brief period of time -- excellent synergy and very refined, natural sound with excellent dynamics.

Both the Power 3's and Rowland 6's are $3,500-$4,000 used, and both were over $10k when new. Power 3's produce a lot of heat. Rowland Model 6's are compact and, by hi-fi gear standards, very attractive.

The Salons and Studios require an amp that can produce current, so my advice is to stay solid-state.

Good luck