Suggestion used tube amp between $1,500-2,000

Honestly, in your price range I think you would be better served getting a tubed integrated amp. Look for a used PrimaLuna DiaLogue Premium HP, or Cary SLI-80. With your speakers I think you would probably need the 80 wpc in Ultralinear, but if your room is small enough, maybe you could use the triode mode,

I’ve owned the ARC LS-7, and it’s not a very good preamp to be honest.
Integrated amps get a bad rap sometimes, but they really do give you more bang for the buck in your price range and even much higher.
I’m currently running a VAC Sigma 160i integrated amp, which lists for $10K, and handily beat the $20K of separates that I replaced with it.
Not only is an integrated amp more bang for the buck, but it’s one less power cord and pair of interconnects to buy too.
Personally, I wouldn't head into the separates market unless I was looking to spend over $30K.

Cheers,
John

Look for Cayin or VAS items, great value and great sound, new or used.  Most of its products are knock offs of vintage Mc, HK and Marantz designs, updated for SOTA parts.  I have purchased a few Cayin products and I found them better then stuff costing three and four times the price.

I'd echo John's recommendation of an integrated. The Cary Sli-80 build quality is excellent, it's easy to bias and gives you a large range of output tube options to tailor the sound to your liking. The small tubes and rectifiers are common types, meaning lots of choices in a wide range of prices. Having service and advice available within the U.S. is a bonus, as well. Most important, it sounds wonderful and is a pleasure to use.

Why buy used?
http://www.quicksilveraudio.com/products/midmono.html