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Review and Measurements of Benchmark AHB2 Amp

anmpr1

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Yep, the AHB2 is a feedforward design. This has a number of benefits including the fact that they can use a relatively low bias while maintaining Class A performance throughout the power range.
I remember my erstwhile Quad 405 had 'feedforward'; but I don't know if it was a similar principle as the THX/Benchmark. On the other hand, the old Quad gear and Benchmark have a similarity: both feature a smallish, no-nonsense, compact, cute 'n cuddly form factor. If Benchmark added 40 pounds to the chassis, a pair of Binghamton Blue watt meters, and some large handles in front, they could sell this for 3 times the price.

Speaking of three times the price, check out the Stereophile Website for their recent Balanced Audio Technology's amp review. Not the idiotic subjective descriptions that can't be deciphered, but Atkinson's measurements. Then marvel that this thing is 'highly recommended'. It underscores why the mainstream audio press is simply an exercise in a) delusion; b) opportunistic salesmanship; c) both.
 

maty

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I have both Ncore’s here and Benchmark and I can’t hear any difference with the passive speakers I have here, they are both excellent , quiet compact, efficient.
Keith

* With very good recordings and high/very high DR?

* Acoustic instruments and natural voices (without Autotune, vade retro satana)?

I ask it because it is the kind of music I listen to almost always.
 

JohnYang1997

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Neat! Can't wait for Chinese to steal this design and start selling those amps at 1/5 the price :p
Well. Ah, Chinese obviously don't care about measurements. They sure will be able to do it but..you just won't see it happen.
 

anmpr1

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* With very good recordings and high/very high DR?

* Acoustic instruments and natural voices (without Autotune, vade retro satana)?

I ask it because it is the kind of music I listen to almost always.

Then this is what you want. Hard to go wrong with Maria's natural voice.

maria.jpg
 

tktran303

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I have both Ncore’s here and Benchmark and I can’t hear any difference with the passive speakers I have here, they are both excellent , quiet compact, efficient.
Keith

Yes they are both audibly transparent.

Why? Our very best transducers have H2 or H3 that is 60dB down (0.1% THD)
See:
https://hificompass.com/en/speakers/measurements/accuton/accuton-s280-6-283n

Or:
https://www.innerfidelity.com/images/SennheiserHD650.pdf

Maybe 70dB for an outstanding unobtainium driver, or a narrow frequency range.

See:

https://www.innerfidelity.com/images/FocalClearsnA1BRQE000007.pdf

But I’ve never seen a transducer, headphone driver or loudspeaker driver, whose H2 or H3 was 80dB down (0.01% THD)
And you don’t want to see what happens with IMD in a speaker...

So of course whatever problem in the amplifier is masked by the transducer.

We’re living in an era where the distortion of amplifiers and DACs are below noise of our audio sanctuary.
 
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maty

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Then this is what you want. Hard to go wrong with Maria's natural voice.

Maria Callas, Carlo Bergonzi, Tito Gobbi - Puccini - Tosca (1965), Vinyl x2, EMI, Germany

https://www.audiosciencereview.com/...t-is-and-why-is-it-happening.3392/post-177987


Well.... some remasters. The vinyl remastered has low DR.

Maria Callas - Callas Remastered (2014), Vinyl, Warner Classics, UK

DR Peak RMS Duration Track
--------------------------------------------------------------------------------
DR14 -0.53 dB -19.71 dB 4:27 01-Habanera (Bizet / Carmen)
DR9 -3.03 dB -18.14 dB 5:40 02-Casta Diva (Bellini / Norma)
DR11 -2.20 dB -18.61 dB 2:37 03-O mio babbino caro (Puccini / Gianni Schicchi)
DR9 -4.50 dB -18.93 dB 4:56 04-Ebben? Ne andrò lontana (Catalani / La Wally)
DR8 -3.88 dB -19.62 dB 3:06 05-Ah, fors’è lui (Verdi / La traviata)
DR10 -4.67 dB -20.33 dB 3:57 06-Sempre libera (Verdi / La traviata)
DR11 -1.31 dB -16.92 dB 3:18 07-Vissi d’arte (Puccini / Tosca)
DR9 -4.51 dB -18.41 dB 4:47 08-Un bel dì vedremo (Puccini / Madama Butterfly)
DR10 -2.76 dB -18.13 dB 4:54 09-La mamma morta (Giordano / Andrea Chénier)
DR10 -3.15 dB -18.99 dB 3:27 10-Donde lieta uscì (Puccini / La bohème)
DR13 -2.53 dB -22.50 dB 6:21 11-Una voce poco fa (Rossini / Il barbiere di Siviglia)
--------------------------------------------------------------------------------

Number of tracks: 11
Official DR value: DR10
 

Kal Rubinson

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Interesting thing about Stereophile is they still went on to praise some other pieces of audiophile jewelry at 100K without reference to the Benchmark.:facepalm:
You are implying that Stereophile is a monolithic entity whereas, in reality, it is an aggregation of individual reviewers. I think most of us are relatively consistent even though our perspectives may be quite different. Can you ascribe the behavior above to any individual at Stereophile?
 

MetalheadRich

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Congratulations Benchmark.:cool:
I remember reading about this amp when it first came out. I even read the Stereophile review.:eek:
Interesting thing about Stereophile is they still went on to praise some other pieces of audiophile jewelry at 100K without reference to the Benchmark.:facepalm:
It seems to me that there isn't a better buy. I agree in general with those who say it performs way past what is audible. If the amp was priced at 50K it would be an expensive excess; it isn't, it's 3K, which in audiophile terms is nothing and for a buy once to have the best for the average audio enthusiast, not much either.
If Benchmark made it five times the sized and at a weight that required and sack barrow to move it, they would probably sell more.;)
All the people I've come across using Benchmark products have had nothing but praise for the products, the service and the reliability.
If I buy another amp this will be it. There is nothing on the market that comes close.

not a better buy? i have an 6 channel NC500-based amp that cost the same and is equally as transparent.
 

Purité Audio

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Half joking there since i have heard Emitter at the store a few times (and it is outstanding to my ears).

How did you like ASR as over all, sound and user experience ?
Thanks
Without speakers the amps are pretty quiet, I had some early B&W 800’s at the time, and they were quite a difficult load, the ASR was capable ( I believe ) of driving them, took up a lot of real estate though.
Keith
 

anmpr1

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You are implying that Stereophile is a monolithic entity whereas, in reality, it is an aggregation of individual reviewers.
The problem (or at least 'a' problem) with Stereophile (and almost all the subjectivist mags--print and on-line) is what you describe. There is no discipline, editorial control, and no method to the madness. [Unless the 'method' is opportunistic salesmanship, something I don't discount.] I remember an exchange I had with the late Peter Aczel. He admitted that the problem with the early Audio Critic was a lack of method. He admitted that he 'instinctively knew' that the Mark Levinson had to sound better than the Pioneer going in to the listening session. There was no control, and no critical analysis of what he was doing. Way back in 1978 or so, Mark Davis, then at MIT, tried to school him on psychoacoustics. At the time, Aczel laughed at him, but some years later wound up apologizing to him in print. He realized that without some control and methodology, it was all useless.

Remember Enid Lumely (sp?). At the time I thought it was Harry Pearson making fun of both the entire high end reviewing scene, and himself. It was only a little later that I realized Harry in fact had no sense of humor, and was serious having this lady write for his mag. I never read another issue, after that. Stereophile lost credibility with me after the way it treated Bob Carver. Now I look at it, on line, simply for laughs.
 

andymok

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I don't have much experience in power and, but I read it has a damping factor of 350, does it considered to be high?
 

anmpr1

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BENCHMARK AHB2 vs. BEHRINGER A500 at the Richard Clark 10.000$ challenge anyone?
Even if it is shown that you can't 'hear' a difference, that does not make the two equivalent. The Benchmark is state of the art, and has commensurate fit and finish. It is worth its price. The A500 is a marginal thing in the build department, but can certainly be considered where cost is the deciding factor. It is worth its price. On the other hand, if cost was no object and I had to make a choice between, say, the A500 and the latest and greatest Stereophile find, the Balanced Audio Tech amp, I'd definitely lean toward the Behringer.
 

anmpr1

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Well.... some remasters. The vinyl remastered has low DR.
I laughed when I first saw the remaster of Callas sponsored by B&W. But the end product is compelling. Sounds fine to me, although I don't necessarily attribute anything to the new and improved sample rate, etc. Nowadays, the big thing seems to be 'remastering' even remasters. It's a sign of the times--really, how many versions of the Four Seasons (Vivaldi, not Frankie) does anyone need? And like I've said before, does anyone really think that Hank Williams' Hey Good Lookin' is going to sound better in hi-res? It's marketing. A gimmick that sometimes works. and sometimes is just an excuse.
 

MZKM

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Sounds like a funny reference. Do you have a source link?

https://www.stereophile.com/content/nothing-what-i-want:

Herb Reichert:
the BP DAC reproduced pretty much exactly what I heard sitting behind the binaural head at the former church in Greenpoint and the Benchmark DAC3 which did not even get close. It conspicuously stripped away a huge amounts of what I and David Chesky know is on the recording.

I use Chesky recording sessions to review headphones because I can compare what I hear live to the sound coming off the so-called “mike feed.” The Border Patrol DAC reproduced the church walls, the reverb, the positions on the floor where the musicians were standing, and all the subtle breathiness of Macy Gray’s voice. With the Benchmark, the majority of that information (which is definitely on the master file and appears via David’s $100K MSB DAC and via my Holo Spring DAC) disappeared !!! Your neutral DAC “stripped” away information that is unquestionably on the master file. Not to mention the BM DAC made it sound hard cold and harmonically threadbare.
 

anmpr1

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I'm reminded of an anecdote where Peter Aczel and (I think it was) David Rich heard a Max Wilcox DAT copy of one of his masters, and thought it was great. When the CD came out both were chagrined, accusing DGG of mucking up the original mix. Aczel called up Wilcox to complain. Wilcox said that it was impossible that DGG would screw up his recording. The two then found the DAT that Max had given them from his master, did a controlled listening, and found that they were indeed the same.

How can a DAC 'strip away huge amounts' of what is on a recording? Does that even make sense to anyone? How could that even happen?
 

DonH56

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I don't have much experience in power and, but I read it has a damping factor of 350, does it considered to be high?

Yes. Opinions vary, but generally >20 is considered inaudible for most people and speakers, and >100 "high". Tube amps often fall into the 5-20 range while SS amps typically exhibit >100. Note, like any amplifier, it falls at higher frequencies.

Damping factor is simplistically defined as the load impedance divided by the amplifier's output impedance: DF = Zload / Zout. The lower the amplifier's output impedance, the higher the damping factor, and the less influence the speaker's impedance will have on the sound. Speakers with low impedance dips and wide variations in impedance are a more difficult load for an amplifier. The lower the amplifier's output impedance (and thus higher the DF) the less the frequency response and sound will change.

HTH - Don
 

Frank Dernie

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You are implying that Stereophile is a monolithic entity whereas, in reality, it is an aggregation of individual reviewers. I think most of us are relatively consistent even though our perspectives may be quite different. Can you ascribe the behavior above to any individual at Stereophile?
I have subscribed to Stereophile for years and have bought paper copies, when available here, for decades.
The only reviews I read throughout now are yours an John Atkinson’s, outside that I look at the measurements and draw my own conclusions.
There are no worthwhile measurements of record player elements and often comments which are just technically incorrect, though confidently expressed. It is very common for people to use static explanations for dynamic systems and be completely incorrect though, even inside the business, though I often wonder if that is so as not to give information to competitors, since the basic engineering knowledge has been out there for decades...
 

maty

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Then this is what you want. Hard to go wrong with Maria's natural voice.

Just now, I have listened to the recording.

https://www.diyaudio.com/forums/music/6958-playing-listening-post5800983.html

And I have written:

EMOTION

Maria Callas, in her years of vocal fullness, is still number one because she transmits emotion, you fall in love with her voice.

What good is technical perfection if you can not get the listener excited?

That is my doubt about such amazing numbers (Benchmark and NC400/NC500), if the feedback has been abused by sacrificing musicality. What good is a spectacular sound if it does not excite? Since I have not heard them, I can not comment.
 
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