Which Solid State amplifier would you recommend for my budget?

+5 Belles, I would suggest the Aria monoblocks.  

Just a general observation here, as I have not heard any of your shortlist.  Please let us know your speakers.  The speaker / amplifier combination should always be considered together.

Parasound

One more to add….musical fidelity m6si.  It’s 2 mono blocks on the same chassis.  I use it drive Martin Logan’s ethos.  It’s has plenty of juice and smooth as butter. 

I agree with the Belles recommendations. If budget is an issue, the Belles Aria integrated is the most muscular 75 watts you can ask for and this model comes with a headphone jack. If you are more interested in a killer integrated with a huge, dual mono power supply,  the 85 wpc into 8 ohms and 130 wpc into 4 ohm Aria Dual Mono integrated is a fantastic speaker friendly amplifier and a great fit with the Spendor D7.2 loudspeaker. If you want more power, choose the Aria Signature integrated with a huge dual mono power supply outputting 125 wpc at 8 ohms and 225 wpc into 4 ohms. With Belles, you just can't go wrong. Two things I immediately noticed with the Belles Dual Mono integrated was it woke up my speakers and exhibits zero listening fatigue.