Odyssey Khartago on eBay with larger upgraded power supply, current bid $500.
Consider a Odyssey Khartago stereo amp used. These pop up for $600 occasionally.
These could also be good, as I believe they also use bi-polar output transistors as well and decent power supply to get some current flowing.
But there’s a ? for me on the mono blocks, from couple of models I saw that came through, they were just stereo amps that were bridged.
+More watts
-More distortion
-Less damping factor
-less stable into low impedance’s.
Cheers George