Small Footprint (compact) amp to power speakers?

Hi all:

Looking for a small integrated amp to power a pair of Onix RS450 speakers.  Probably need 50W, at least.   I'll only be using it to stream to via Chromecast Audio.  

I've looked at the AudioEngine N22 but it doesn't have enough power. Even the NAD 3020 might not be enough.  Planning to spend under $500 used/new.  

Any suggestions?  I don't see many "compact" amps out there.  

Thanks.