Recommendation for integrated amplifier for Paradigm Studio 20s v.5

I would not go all tubes for this speaker, given the impedance curve. I'd go hybrid, and would consider Rogue, Vincent in your price range. 

I can offer 2 suggestions that fit into your budget.

I once owned a pair of the Studio 20s Version 4. Drove then with a 100 wpc Vincent Audio SV226 hybrid integrated in a 12 x 15' room.  This pairing was wonderful. The tube linestage provided a smooth texture or bloom while the 100wpc SS amp maintained the dynamics these speakers provide.  I believe the latest version is called SV-228. Not sure. I would look up Audio advisor which have sold Vincent products for years. The Vincent SV-500 at 50wpc likely won't provide the same drive as the SV226 did. Much depends on how loud you listen. Your small room size would help. 

Anothe possibility is the Rouge Audio Sphinx V3 which is also a hybrid using a tube linestage coupled witha  class D 100wpc SS amplifier.  I currently have this amp in a second system. Rogue Audio is also sold by Audio Advisor. 

Th4 Rouge Sphinx has a phonostage, the Vincent a built in DAC.

I am not affiliated with AA, just a satisfied customer. 

Thanks all.  Sounds like there are a lot of options.  I'm intrigued by the hybrid route and will likely go that direction.  

Yes the Rogue Sphinx is getting great reviews.