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

128x128gunmetalzin
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)