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Benchmark AHB2 Review (Updated Measurements)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 7 2.3%
  • 2. Not terrible (postman panther)

    Votes: 5 1.6%
  • 3. Fine (happy panther)

    Votes: 47 15.3%
  • 4. Great (golfing panther)

    Votes: 248 80.8%

  • Total voters
    307

DHT 845

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While it's a nice amp alright, I would take an Apollon NCx500 amp over it, let alone for 1/3 of the price.
Exactly! And Apollon NCx500 with Neutrik Speakon NL-2 option (that is absolutely free, no price change) should be even better in performance than Apollon with binding posts reviewed on ASR.
 

Purité Audio

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I get that this was state-of-the-art since being announced in 2014 (ie 9 years ago).
But recent advancements in class D amps, from Purifi and Hypex, have pushed the boundaries of technology and now are considered state-of-the-art.

Ignoring the price, what makes this a better buy than the current state-of-the-art options of today?
The Benchmark is a super amp, completely silent, reliable, powerful but in terms of sound quality I couldn’t hear any difference between them and the March Audio hypex/purifi designs we were using at the time and if you, look at their respective measurements I wouldn’t really expect to.
Keith
 
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This is 150 USD used. Just to throw in some perspective.


It is actually remarkable. I was watching the dashboard and noticed neither the gain, nor the output power was changing. Totally static display. Thought AP software had hung! Then I looked on the right and SINAD was changing a tiny bit so nothing was hung. The amp has remarkable precision and stability.
I'm sure QC is top notch at Benchmark but if components in the circuit is of high quality surely reality will follow simulation quite well. You pay for both if you buy one. It's a feature of a top quality product.

The interesting thing is that there’s a difference. And for those interested in the SOTA, it’s a downside to the anp, even if it can’t be heard. Can we explain it?

Hopefully the binding posts aren’t “cheesy steel parts” lol!

1703846825973.png
 

TheWalkman

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That’s a great review. Thanks (but not really interested.)

As a happy Audiophonics AS400 owner, I‘ve been permanently cured of Benchmark Envy. I’m a happy Purifi customer who isn’t looking (listening?) back. Nor am I in the market for another amp. Finis!

I’ll take the $1000 / db savings (111db vs 109 for the AS400) and invest it elsewhere.

Cheerio!
 
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lordhumungous

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The Benchmark is a super amp, completely silent, reliable, powerful but in terms of sound quality I couldn’t hear any difference between them and the March Audio hypex/purifi designs we were using at the time and if you,ook at their respective measurements I wouldn’t really expect to.
Keith
Except for turning amp on and off . There is some noise during that process .
 

lordhumungous

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While it's a nice amp alright, I would take an Apollon NCx500 amp over it, let alone for 1/3 of the price.

I did . And I like it better , a lot more power .
 

AudioSceptic

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Back in 2019, I reviewed the Benchmark AHB2 Stereo Amplifier. I received a second sample from a kind member to update the measurements. Originally the AHB2 cost $3000 but now, $3,500.
View attachment 337815
As you see, it is a compact but very nice looking amplifier. I appreciate the clipping indicator which seemed accurate in testing. Back panel shows both SpeakOn and traditional binding posts:
index.php


In my original testing, I used the SpeakOn connectors as that gave better response than the binding posts. They are directly soldered to the PC Board as opposed to extra wiring. The amplifier is so low distortion and sensitive to load modulation that this makes a difference as you see below.

A very nice feature is three different gain settings. Highest saturates around 2 volts, middle 4 volts and lowest around 10 volts. I measured all three in areas that matter.

You can also bridge the amplifier into mono and get massively more power. Again, see below.

Benchmark AHB2 Amplifier Measurements
Let's start with our usual dashboard in low gain:
View attachment 337816
While this is phenomenal performance, we have gone from SINAD of 113 dB to 111 dB. This is due to third harmonic rising (inconsequentially to -120 dB). So ranking goes down a bit:
View attachment 337817
View attachment 337818

Surprisingly, there is not much degradation at higher gain levels:
View attachment 337819
View attachment 337820

This is reflected in the SNR:
View attachment 337822
View attachment 337823
View attachment 337824

I did discover some load dependency:
View attachment 337825
It is well managed though and is outside of audible band.

Intermodulation distortion is expectedly low:
View attachment 337826
View attachment 337827

Crosstalk is a hair worse which could be the different speaker wiring:
View attachment 337828

Let's run our 4 ohm power sweep at all three different gains:
View attachment 337829
You see again the impact of the speaker binding vs SpeakOn. But still excellent performance.
View attachment 337830
The dependency on wiring goes down at 8 ohm due to lower currents involved:
View attachment 337831

Changing frequencies doesn't impact the amplifier power sweep much except at 15 kHz, and even there it is well behaved:
View attachment 337837
Some of the non-linearity may again be due to binding posts.

Amplifier is stable and performant on power up:
View attachment 337832

Benchmark AHB2 Bridge Mode Power Measurements
The amplifier goes into differential mode which in theory quadruples the power. It is however only rated above 6 ohm. I tested it at 8:
View attachment 337833

Benchmark AHB2 Reactive Power Measurements
Using my Loadbox, I tested the amplifier at different complex and resistive loads down to 2 ohm:
View attachment 337834

There is a bit of voltage droop as we go down from 8 ohm but still respectable when you consider how much power is being pumped out (approximately):
View attachment 337835

Here is the same but in bridged mode:
View attachment 337836
As you see, it also doesn't have any issues with reactive/complex loads.

Conclusions
Using standard binding posts reduces performance just a bit but certainly nothing to worry about. What we have is still state of the art and one of best ever consumer stereo amplifiers produced.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
What a nice result. You pay for top performance and you get it, and no nonsense like VU meters!
 

beagleman

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The volume has to be tiny and QC tolerances must be very rigorous. It’s built to last decades and maybe could be passed down to your children if properly maintained. Also, people who designed and built this deserve a living wage.

This ain’t a mass-market AVR assembled in an enormous factory by robots with parts selected for post-warranty obsolescence and landfills.

Amortize the price by a reasonable number
of years of use before major service and it’s probably quite cheap. And I best resale value is very good in five years or ten or 15-20 when it will be considered one of the last great CLASS AB amps ever made.

a quality purifi or ncore amp may have similar or better amortized lifecycle costs, though I suspect power supplies may not age as well.

One can easily drop the same amount on a fancy but not great avr that will be obsolete whenever Dolby comes out with a new whiz-bang codec or HDMI standards shift.

I think he just literally meant "Its a LOTTA money" no matter how you slice it;)


I buy all of my AVRs used, and take advantage of their low resale value. Never spent more than $300.00 for one....Its a dual edged sword.
 

DSJR

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What a nice result. You pay for top performance and you get it, and no nonsense like VU meters!
Aw but I LIKE VU meters after decades of brainwashing that made us remove external tone controls (allowing fixed simple filters in the circuit line amp) and visuals such as meters :D
 

Fidji

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Still a great amp. Too bad it costs so much!

ASR has 2 defaults line of posts
a) expensive product measures badly/average - hahahahah Apple dongle/10 usd IEM is better, hahahah, audiophools, hahahaha (see Susvara)
or
b) product measures excellently and costs more than Apple dongle - “why it cannot cost 10usd, soooooo expensive”
some people (not you specifically) are just hard to please. Specifically for Benchmark - you get value for what you pay for.

BTW I know a person with VERY expensive speakers (6 digits) that uses Benchmartk pre + amp, and is very satisfied.
 

Rosenbloom

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I have Benchmark DAC and have been thinking back and forth if I should buy a pair of Genelec 8341 or AHB2 + passive speakers to complete my system. I always thought Genelec was the way to go but whenever I read good reviews on AHB2 I became not so sure. XD

My Benchmark HGC has been sitting in the box as new for months. LOL
 

Sokel

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As a measurement nerd,I know that I'll never hear this difference and it's about conditions too but I cannot help but watching it:


Benchmark AHB2 Stereo Bridge THX Power Amplifier Power vs frequency vs distortion Measurement.pngApollo NCx500ST stereo class D amplifier hypex NCOREx NCx500 lowest gain Power 4 ohm vs freque...png

(don't start the blah-blah,is visual to me,I'm as superficial as it gets)
 

poopy

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As a measurement nerd,I know that I'll never hear this difference and it's about conditions too but I cannot help but watching it:

(don't start the blah-blah,is visual to me,I'm as superficial as it gets)

Thanks, was just about to post the same to put an end to this unjustified AHB2 trial...
 

welwynnick

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Agreeing with the above, what's interesting is that the binding post measurements and hence the SINAD Leader Board are relatively little affected by the 5W performance, it only really degrades above that level, much like the Hypex amps.
 
D

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As a measurement nerd,I know that I'll never hear this difference and it's about conditions too but I cannot help but watching it:


View attachment 337916View attachment 337917

(don't start the blah-blah,is visual to me,I'm as superficial as it gets)

I guess this is like the feeling you have if you have ever renovated a house. You know everything is A okay. -But.. There's this little sweeping list or detail that only YOU know was made in haste. Only YOU know that this is not quality work. And it's barely able to live with.. A burden you have to carry.
 

Sokel

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I guess this is like the feeling you have if you have ever renovated a house. You know everything is A okay. -But.. There's this little sweeping list or detail that only YOU know was made in haste. Only YOU know that this is not quality work. And it's barely able to live with.. A burden you have to carry.
I'll only tell you my architect is a super hero.
Not by my comments about stuff but by my face expressions only when we were building our house.

(I would get me a restraining order if I was him :p )
 
D

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I'll only tell you my architect is a super hero.
Not by my comments about stuff but by my face expressions only when we were building our house.

(I would get me a restraining order if I was him :p )
LOL

Know the feeling. [reaches out to hold hands]
 

AdamG

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