I need help with an amp decision

Equipment: Tannoy xt 8 (91 dB/Watt sensitivity and 400 Watt peak power ), REl s/510, Black ice f360, and an audiobyte black dragon dac. 
Room size:17x21x10h
Music preference, everything but rap and pop, 
question: Can I get some suggestions regarding a solid-state amp choice for this system, please.
I can not use mono amps because of the sub and I really do not want to go the route of a tube amp. 
Two amps I have been thinking about are the benchmark AHb2 or a first watt ?, I will be trying to shop the used market. Any suggestions, would help. thank you

If you're considering First Watt and want balanced inputs then you can only choose from the J2, F1, and Aleph J which produce 25, 10, and 25 watts, respectively.  You're room is pretty big but if you don't need big volume you should be ok with the J2.
soix’s question is a key one, as is the budget for the amp

afaik, nelson's first watts don’t run balanced ins in standard stereo configuration -- (e.g. the f4 has a balanced in, but it is used only if run as a monoblock)
Consider an NAD C298.  It is $2K new.  I just took one of these in on trade and am NAD dealer so I have spent some time with it.   It is stupidly good for the money.  IMO...maybe the best amp you will find under $3k.  It is Class D but you won't know.  It needs a little time to burn in but this amp is far better than you would think.  Not a hint of brightness and will deliver wonderful, controlled bass with lots of detail.  

You may struggle to find this used not because they don't come up.  Mine sold in 5 minutes.  This is the same amp in the M33 which one product of the year and sounds incredible.

Another option would be the Rogue Hydra.  Lists for $3K and can be had in the $1500 to $1800 range used.  You will want to swap in NOS tubes if it still has the stock JJs.  A pair of NOS Cifte/Mazdas or Mullards will make the amp shine like the sun.  And, since it is class D, it behaves like SS and the tubes need to be replaced every few years at most.  

As I mentioned above, I am an NAD dealer.  I have no affiliation with Rogue.  I just personally have owned a Hydra for several years.  
Thank you for the feedback so far. Sound characteristics for the amp would be a good sound stage along with a neutral presentation. My room cannot be sound treated to my liking and I'm a little sensitive to treble so the amp cannot be harsh to the ear. Monoblocs and another sub is the goal but is a future goal. For right now my budget is about 2k in the used market. Thank you for the suggestion on the NAD and Rogue, I will look them up. 
I ran Tannoys somewhat like yours years ago (Tannoy Eyris DC3), plus I’ve had many more Tannoys. They do well very with Rogue tube amps for the money, and I can whole-heartedly recommend these (especially a Stereo 100 or Stereo 90 Super-Magnum), but you specifically requested SS. I’m sure Rogue’s hybrids (Hydra, Dragon, Pharaoh) sound quite good, but I just never felt the desire to jump into class D so I haven’t tried them. Also I’m very much not a fan of the 12au7 tubes they use in their front-end - I can tolerate *some* 12au7 in a tube circuit, but these are literally the only tubes in these hybrids.

I also have had great pleasure running Tannoys with the Parasound Halo series amplifiers. Even the entry level A23 (today’s A23+ should be even better) should sound amazing with your Tannoys. And you can move up from there, as you like (A21, used JC-1). Wonderful, warm and smooth sound not totally unlike tubes, but with the punch and power of SS. Music lovers can truly enjoy the Tannoy DC / Parasound combination.
The First Watt J2 has balanced inputs. I’m listening,and looking at mine this very minute. 
Harmon Kardon Citation 16 but no balanced connections.  One of the sounding SS amps for the money.  Older but so easy to upgrade for audio bliss.  Or look for the BEL amps  very musical and easy to upgrade again.

Try to find a used parasound hca 3500 or a used parasound a21 amplifier with a good preamplifier like a tanberg 3002a or 3008a.
I think First Watt is a great choice but don’t think they have balanced inputs.  There’s a McCormack DNA-125 on US AudioMart for $929 that’d also be great and can be sent to SMcAudio for further upgrades if desired, but that too has only single-ended inputs.  TMR has a Parasound A21 here, but I think they also have an A21+ for $2399 if you can stretch.  Personally I’d forgo the balanced inputs and go with First Watt or McCormack, but that’s me.  Best of luck. 

@rocray corrected us, the new-ish j2 is the rare first watt amp with xlr inputs... 25 wpc single ended in 8 ohms, 13 wpc in 4

might be a good match for op’s tannoys

I wouldn’t be happy with just 25 Watts @ 91 dB/Watt in OP’s relatively large room, but I do like to play loud. I’ve had 93dB Tannoys and upgraded from 25 - 35 Watts to 70 and then 100, and it was notable each time. This will depend on listening habits, but it’s something for OP to keep in mind. Yeah, I know 1 Watt can be "hella loud". It can also be completely inadequate at other times.

I've seen Tannoy lovers with Pass labs amps so it must be a good match, but usually they're using the higher powered models. Again, depending on budget, I think a Parasound Halo A21 or A21+ could be a good way to go here.
With the FW offerings, it’s probably not a good choice if you like to take a dive in the mosh pit.  I don’t listen very loud usually,but when I do,the J2,and my F5 give me all I need. But there are folks that would say my version of loud,is their version of elevator music.  
I’d go with just about any McCormack, and send it to Steve for his tweaks. You’ll come in under budget and keep it forever. Have fun!
Good God man you can get a DNA125 and have Steve breathe on it. What are you waiting for??!😍 
LOL I don’t know if MC is trolling or if he really likes the DNA amps. MC - I do really enjoy your posts and passion, though we don’t always agree.

Tannoys do very well with SS amps that are smooth and maybe a bit on the warm side, so if the DNA amp is like that it’ll be a good match.
Most definitely time to move into the 21str Century. LSA Voyager 350/650 wpc GaN amp
MSRP $3000, and a trade in discount
Wow, 400 peak allowable?

    200-250 continuous?

  You need an amp that will control these. You need an amp with about 300@8. /  550-600@4

  you will need it.

I know a broken horse.......l.l.crescendos, and bass drum, etc, needs the headroom to properly drive these speakers!

 Don’t mess around with anything under 300 WPC!
Thanks for all the feedback. However, I made, a change in speakers and got an amp. I now have a set of Tannoy DC 8's which have a rec amp power of 30-175 watts rms, Sensitivity 88db and peak power of 350 watts. They are an 8 ohm and frequency response 42hz-35kHz. I also bought a used Gamut D200mk which has a continuous output power at 230V mains voltage 2 x 200W / 8 Ohms 2 x 400W / 4 Ohms. I think the set-up sound awesome! and I'm very thankful for all of the advice and suggestions given. The info was a big part in my choice of equipment . Thank you again