I suspect that Wind Chaser may be correct regarding the differences of experiences with the AHB2. I was initially quite impressed with many of the reviews of the AHB2 as well as the remarkable testing results. In addition, I spoke with individuals knowledgable about Martin Logan speakers including some at Martin Logan who had excellent results using the AHB2 with hybrid Martin Logans. I have Martin Logan CLX's which obviously are nearly full range electrostatics and have a difficult impedance curve.
In my system I have used a number of well regarded amplifiers over the years with these speakers including Pass Labs XA100.5 monoblocks, a Krell 402e, and an Audio Research Ref 150 to power the CLX's. I am currently using a recently manufactured Coda 15.5 which remains in Class A up to 100 watts and then transitions into AB up to 150 watts but is stable down to at least 2 ohms. The Coda 15.5 drives the Martin Logan CLX's reasonably well and in my imperfect audio memory better than its predecessors. Being the curious audiophile that I am, I purchased a single AHB2. The upside is that it does have high signal to noise and outstanding transparency with the CLX's. The downside was its lack of harmonic density and a lack of mid to upper bass dynamics which may be due to the capacitive character of the impedance of these speakers. As I mentioned previously, seasoned audio reviewers noted similar findings in using the AHB2 with Monitor Audio speakers and Muraudio electrostatics. I would add that these changes were apparent without clipping. While personal preferences in audio and differences in systems may account for differences in subjective responses, I am curious if the more technically knowledgeable members might have some thoughts on the technical basis
of such AHB2/speaker interactions and whether the extra voltage provided by using 2 mono'ed AHB2 might remedy these suboptimal responses.