Benchmark Media AHB2 power amp

[hifinutt]

Following on from the ayre codex review from audio science i notice he is extremely positive about how it measures .

AHB2_Silver_Top_01_2000x by https://www.flickr.com/photos/158267783@N02/, on Flickr

benchmark ab by https://www.flickr.com/photos/158267783@N02/, on Flickr

some blurb from a review to give some background

The only word to describe this amplifier is tiny! Measuring just 11.04" wide by 3.88" tall and 9.34" deep, including feet, heat sinks, and binding posts, it weighs in at only 12.5 pounds! The actual amplifier circuit itself fits in the chassis space of only 8.32" by 3.88" by 7.88"! That is slightly less than one quarter of one cubic foot! Do you realize how small that is! So, just how good can such a miniscule Class D amplifier sound? That was my first completely erroneous thought too. Folks, this isn't a digital amplifier at all; it is a linear amplifier built on technology developed and patented by THX Limited, of San Francisco, California. Yes, that THX.

The AHB2 (named in tribute to Allen H. Burdick, who founded Benchmark Media Systems in 1983) uses a switching power supply with rails regulated at +/- 45 Volts. It is a hybrid amplifier, using a Class A-B design that also employs signal tracking to modulate the voltage on the rails according to the amplifier's actual demand at any given moment. This next part is where the real magic seems to take place, and is the one that Jayant prefaced in one of our phone conversations with, "You're not going to like this..." The next few sentences he spoke to me contained the word "feedback," several times!

http://www.enjoythemusic.com/magazi..._Media_AHB2_Stereo_Power_Amplifier_Review.htm

now the audioscience review mentions some thoughts

such as :

"I hope your jaw is on the floor just like mine was when I saw this picture emerge! 113 dB THD+N in a power amplifier? Are you kidding me?

Look at the harmonic distortion. The worst case spike is below -130 dB! This is insanely good. Of course this type of SINAD (signal and noise ratio) crowns the Benchmark AHB2 as the best I have ever tested:"

It goes without saying that the Benchmark AHB2 breaks new ground with respect to performance of power" amplifiers. Using it, you can be assured that any distortion that you hear is from other sources
(speaker, source, content, etc.). This is what I look for in high-end audio: absolutely the best performance so no second guessing is involved.

https://www.audiosciencereview.com/...-and-measurements-of-benchmark-ahb2-amp.7628/

I have previously read a review in hi fi critic [ apr-june 2016 ] which in listening tests was not that complimentary ...

have you guys tried one and what did you think of it ?

 

[Purité Audio]

They are excellent amplifiers, silent powerful, you can run them bridged, all you would ever need.
Keith

 

[Guest432]

Where do the valves plug in?

 

[DavidS]

Always wondered about these although measurements do not make music.

 

[hifinutt]

Always wondered about these although measurements do not make music.

so true !!

 

[DNM]

I have previously read a review in hi fi critic [ apr-june 2016 ] which in listening tests was not that complimentary ...

have you guys tried one and what did you think of it ?

Before going down the active speaker route, I bought one of these from Keith @ Purite Audio to power some LS50's in a DSP integrated multi-sub setup.

Whilst the LS50's weren't running full range, I still wanted the most powerful and transparent amp available to replace the Chord integrated amp I was using at the time.

The Benchmark on paper fitted my MO, i.e. to acquire an amp with no sonic signature no matter what speakers it was powering, even at high volume levels, in the knowledge that when combined with a good DAC/DSP Pre, what I was hearing was 99% speaker/room acoustics, the recording quality not withstanding.

My observations FWIW:

-With ear up against the tweeters, the Benchmark was deathly silent, even at full volume, unlike the hissy Chord.
-knowing the LS50's, with their combination of low impedance and phase angle in the mid bass are a difficult load, I listened to them full range without subs for a day before the Benchmark arrived. After swapping over to the Benchmark, it was night and day ... well subjectively the Benchmark was in greater control of the speakers, tighter bass and more detail retrieval, although in fairness, the Chord had a pre-amp in the signal path.
-I liked the sensitivity adjustment.
-The Benchmark is tiny and whilst very well made, it won't impress your neighbours or forum friends like large statement amps with fancy casework or glowing valves, unless they value SQ achieved through sound engineering excellence and objective measured performance of course!
-It may expose nasties in your system, up or down stream of the amp, which some punters and certain subjective reviewers might blame on the amp, especially if Benchmark don't advertise in their publication!
-If I ever have passive speakers again, I wouldn't hesitate to buy another Benchmark, or two in dual mono if required.