I had a pair of speakers that were sensitive to source, the kef R105/3 with kube. I finally found an amp krell kav300il integrated that smoothed the rough edges in the upper mids/treble. Even with a 2nd power amp driving the woofers the krell would overheat and require service. Once the warranty ran out, the model was discontinued and the unit failed again I went back to trying different amps, but I ended up building an entire new system because I couldn't get the synergy back.
Most companies outsource the different parts in their products so you might be able to go around the amp brand and locate the manufacturer of the $300. part, might even end up only costing $150.