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I asked Carl Pultz for comments on his ahb2 amplifer & he obliged with a
very nice, quick review (thanks, Carl:)



Sure, I'll try to be descriptive without getting too poetically subjective.
First it took 'clean' to a new level in my experience. It holds on to
high-level signals so that there is less loss of articulation on complex
signals than I was used to hearing, and usually blamed on my speakers.
There is also no audible fizz or low-level distortion to modulate the
music, which allows more sonic texture to emerge and seems to preserve more
timbrel (word invention?!) color. This is reminiscent of a tube amp in
clarity and lack of grain, but a quality that is preserved at a much wider
range of power than is typical with a 40 - 60 watt tube amp. In fact the
Benchmark has a consistency of tonal balance and character across the range
of pitches and dynamics that is better than anything else I've owned. The
impression of openness and clarity at very low volume is exceptional. The
two channels must track each other very closely because imaging,
particularly center placement, is unambiguous. As good as some other
visitors to my house have been, Bryston 4bst, Parasound 21, Odyssye
Stratos, Sim Moon, my rebuilt Dynaco Mk. IIIs, or Coda and Krell and ARC in
my past, the Benchmark is a combo of all their strengths and none of their
downsides. I am annoyed by minor details. Apparently EU mandate requires a
timeout. If there's no audio after 30 minutes, the thing shuts off. It's
surprising how many times it happens when I'm moving between tasks. The
remote trigger thing is weirdly useless in its interface with the DAC. The
binding posts require narrow spade lugs and flexible wire, or else banana
terminals. Often, when switched on, the protection kicks in for no reason,
so an off/on cycle is needed to start it up. It sounded bright and weird at
first, so I used cables similar to what Benchmark sells - Canare mic cable
and a Belden twisted quad. After 30 hours or so, the sound smoothed out and
better wire could be used. I've settled on the Swedish-made Supra quad
speaker and balanced interconnect for now. Madisound sells it - good value.
That wire was too bright in context with the brasher treble of the DAC1.
With the smoother character of the DAC2, it works nicely. My speakers are
small-batch two-way monitors, using RAAL ribbon tweeters and Accuton
ceramic woofers. Quite revealing.
http://www.clearwavespeakers.com/webapps/p/98515/300200/723936 Because the
whole thing is so quiet, I expect it would work well with high-sensitivity
Klipsch and Altecs, etc. Power is not limitless. For a big room, you'll
want two, bridged. So do I, but it would be crazy overkill in my modest
space. For what it does, I think $3k is reasonable, and for $5k, the
dac/amp makes a fantastic system.



Carl Pultz



Tom Fine mentioned that Gary Galo reviewed the unit – a terrific review
IMO. The review is available here:



http://benchmarkmedia.com/blogs/reviews/17600505-ahb2-review-gary-galo-audioxpress



Gary Galo makes a potentially crucial point about the cost savings
from the amplifier’s built-in power-line regeneration:

 the reason for the lack of audible difference [with and without
power-line regenerators or conditioners] might be because switching
power supplies are AC regenerators... THX AAA circuitry's excellent
power supply rejection ratio undoubtedly contributes to the
amplifier's immunity to noisy power lines. This is an important factor
when considering the AHB2's cost. Since you won't need to spend a
large sum of money on exotic power line conditioning or regeneration,
your amplification's real cost may actually be less with the Benchmark
amplifier. In my own case, more than $6,000 of mono amplification plus
two regenerators was sonically beaten by a $3,000 amplifier with no
regeneration. This makes the AHB2 seem like an extremely good value. I
do recommend a basic, but high-quality, line filter/surge protector,
as insurance against lightning strikes and other potentially damaging
power line anomalies.

L. H. Kevil