Desire to try tubes

I will say that if the higher powered SET amplifiers are well designed and built they can sound fabulous.  As others who have posted on this thread can attest to,  211,845,805, etc.  can be used very successfully.  I've have heard wonderfully emotional engaging sound from good quality 845 SET amplifiers. Implementation is key.
Charles 

Hi needfreestuff,
No stupidity, no problem.
Sometimes people confuse the 845 and the 805 tube amplifiers made by Line Magnetic.in SET topology an 845 tube will yield 20 to 30 watts per channel (Depending on the chosen operation point utilized).
The 805 is capable of providing 45 to 50 watts per channel from a single tube.

Mozartfan no doubt speaker choice is pertinent if using lower power SET amplifiers. The Hersey is so easily driven that one can achieve superb sound with a good quality px25 or 300b SET (6 to 10 watts per channel range) in a room with the OP’s stated dimensions.
Charles

The Line Magnetic amplifier that provides 48 watts per channel is the 805 single tube SET (805ia). In order to get 48 watts from the 845 tubes they'd have to be either in parallel SET or in a push pull circuit. The 805 is the more powerful of the two.
Charles 

Hi facten,
Even the Line Magnetic 845 SET is a lot of power for the Kiplisch Hersey. I have no doubt that it would sound sensational. Agree that the Finale and Triode Lab brands are terrific choices as well.

Dennis Had SEP amplifiers as mentioned by wolf_garcia is another very good option (Just not sure how often these are built by Had).
So many really good tube amplification choices, one could get dizzy 😊.IMHO low power SEP or SET would be simply  ideal with the Hersey. Purity, tone and transparency.
Charles

Hi Veerossi,
I also think that the Line Magnetic 805ia  is an excellent recommendation. One minor correction, this integrated amplifier uses 300bs as driver tubes. The output tubes are the DHT 805 producing 48 watts per channel. That’s a lot of SET  class A power for the very efficient Herseys.
Charles

Hi facten,
Thank you for your kind comment.  The OP admits he is new to this endeavor.  I just wanted to assure him that with reading, time and patience he'll realize that 5,000.00 can go pretty far if he's careful and learns more about the high end marketplace. There are a lot of good choices available. 
Charles 

Billeauxbrew,
You have received some very good recommendations.
You have several factors in your favor that can help you fulfill your stated goal. 1Your speakers are both high sensitivity and are known to be easy to drive. You do not require much power so the focus can be on power quality as opposed to quantity.

2 Yout budget range opens the door for some really fine options.
3 Your room dimensions aren’t cavernous so again no need to chase high power amplification.

Some have suggested tube integrated amplifiers and that makes a lot of sense. However I don’t agree with the idea that seperates components are a waste of time. Not true. For roughly the same cost of a Raven Blackhawk integrated here is a highly competitive alternative using seperates.

Atma-Sphere UV-1 preamplifier that utilizes a very simple class A circuit using 6SN7 tubes. Built and backed by the esteemed Ralph Karsten.

Coincident Dynamo MK III el 34 in a single ended pure class A circuit that’d hard wired. 8 watts (Plenty for your speakers and certainly your room size). This is a very high quality built amplifier.

These two excellent separate components will provide you superb sound quality for very reasonable cost. For a bit more money the Dynamo can be built as a 300b SET rather than the SEP el 34. This combo will give any similar priced tube integrated a serious run for the money and may possibly exceed them. There’s plenty of information and reviews available for both of these highly regarded components.
Charles