"Starting with Dakota Staton’s album ‘Round Midnight from the original Capitol release, issued in 1960, I connected the Benchmark to my Quad 57 electrostatics."
"Staton’s vocal delivery was calm, even and smooth without any edginess to her delivery and certainly without any brightness or blooming during crescendos. Her even-handed vocal delivery was very pleasant indeed."
"As for the instruments backing Staton, I was impressed by the tonal accuracy of the introductory strings and the clarinet. Both, backed by the similarly impressive low noise nature of the soundstage, had room to express themselves that enhanced the richness of their performance."
"Everything was in order and everything was in its place. Part of the reason for this was the low noise so, right from the off, the music was much more focused than many other components."
"Bass was never one dimensional but had a layered personality of its own."
"Neat in construction, busy in terms of features and small in stature, the AHB2 is quite remarkable in how it goes about its business of delivering music. I’ve seldom heard such a balanced, easy on the ear power amplifier as this that also provides tonal accuracy plus an attractive space in the midrange. The AHB2 would be an ideal fulcrum to any hi-fi system, acting as the heart around which you can build up your hifi chain. It’s dependable and rock solid. The perfect heart to any hifi."
- Paul Rigby, The Audiophile Man - audiophileman.com
In his review, Paul Rigby mentions driving Quad ESL-57 electrostatic speakers using the AHB2 in bridged-mono mode. Potentially, this mode will provide too much output to the ESL-57 speaker and this may cause damage. The ESL-57s are rated for a maximum input voltage of 33V. The AHB2 can deliver 40V in stereo mode and 80V in mono mode. Mono mode can severely overdrive the ESL-57 speakers and may cause permanent damage to the electrostatic panels. The AHB2 should be used in stereo mode when driving ESL-57 speakers. Apparently the AHB2 gain switch was configured for a lower gain than Paul's other amplifier. This led him to believe that the AHB2 needed to run in bridged-mono mode when driving his ESL-57 speakers. The correct action would have been to turn up the preamplifier and/or adjust the gain switch on the back of the AHB2.