What used amp should I pair with my newly acquired Monitor Audio GR60's?


Would like to spend under $500 or so. Currently using a Pioneer Elite VSX-52TX which has a broken 2nd zone binding post, so no bi-amping from it.

Looking to upgrade to a nice 2 channel. Should I be looking to try & bi-amp ? (or tri-amp? which you can do with these, but not at this price limit)

Any help appreciated.
Thanks.
ring30
At that price point I have found  the Jaton Operetta AV 5140 to be an excellent all-around performer.  I prefer a more detailed sound with sharper image focus/outlines and a tighter bass.  These Jatons are frequently available in 4 or 5 channels so you could use 1 amp to biamp your speakers, which is exactly what I did with very good results.  

Sonically, these amps are (for the price new) quite detailed and rather neutral though the bass may stand out a bit, not being exaggerated, but having more weight and slam than many I've heard.  I think power rating is 70w/8ohm  140/4ohm and has been plenty for me with several speakers with average efficiency even when played quite loudly.  

For what they sell for on the used market, I can't imagine you could do much better.  There is an upgraded 2 channel one on USAudiomart for only $300!   And in all honesty, I felt it bettered a Cambridge Audio 840W which I'd been using until I got the Jaton.  The Jaton was a bit more detailed and seemed more transparent.  Both are monsters in the bass department.  Appearance-wise, especially in pics, they do look like very little more than a small step up from some A/V receivers but in person, they are quite substantial.  For the money, I think you'll be very satisfied.
thanks.  I will look into it.  Someone else mentioned I should check this out:  https://www.usaudiomart.com/details/649730297-belles-soloist-5-amplifier-completely-refurbished-all-...

what do you think & how do you think it would compare to the other?
thanks.