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Review and Measurements of Benchmark AHB2 Amp

John_Siau

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You talking nonsense @Paradigm5h1f7 and you know nothing about amplifiers. Not so surprising due to mass presence of unqualified posters here.
Hey guys, go easy on @Paradigm5h1f7. It is a common mistake to assume that the AHB2 is class-D. The small size and high efficiency imply a class-D topology. The switch-mode AC/DC power supply adds to the confusion.

The AHB2 is a very unusual amplifier and it takes some time to wrap your head around what is happening inside. Some of the technology is disclosed in the THX patents, but there are additional features that we consider proprietary.

For those of you who are very familiar with the inner workings of amplifiers, it may surprise you that the AHB2 has no bias adjustment, nor does it need one. Due to some proprietary circuitry, THD does not change with temperature or loading. Furthermore, there is not a single trimmer or adjustment in the entire amplifier. This means that the performance is not determined by the accuracy of the trim adjustments nor is it impacted by the drift in these adjustments over time and over temperature.
 

617

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@John_Siau I've noticed that the enthusiast amplifier space is dominated by 'modules' which allow everyone from hifi companies to guitar amp makers to make a variety of amplifier and powered speaker products simply by providing AC power to an off-the-shelf amplifier board. ASR has measured some of these modules and the performance is generally very good and in many cases superlative. Do you think the technology embodied by the AHB2 lends itself to this sort of application, or will it remain in dedicated high performance amplifiers?
 

Sal1950

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Do you think the technology embodied by the AHB2 lends itself to this sort of application, or will it remain in dedicated high performance amplifiers?
 

eyes-on-you

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The measurement data have now been posted online: Link
How it is worse than NAD M23?


AHB2

Messwerte​

Dauerleistung an 8 Ohm (1kHz):108 W
Dauerleistung an 4 Ohm (1kHz):200 W
Impulsleistung an 4 Ohm (1kHz):- W
Klirrfaktor bei 50mW (1kHz):0.024 %
Klirrfaktor bei 5W (1kHz):0.001 %
Klirrfaktor bei Pmax -1dB (1kHz):0.018 %
Intermodulation bei 50mW (nach DIN):0.00067 %
Intermodulation bei 5W (nach DIN):0.00078 %
Intermodulation bei Pmax -1dB (nach DIN):2.28 %
Rauschabstand ab Hochpegeleingang bei 50mW (1kHz):92 dB
Rauschabstand ab Hochpegeleingang bei 5W (1kHz):112 dB
Dämpfungsfaktor an 4 Ohm bei 63Hz/1kHz/14kHz:48/45/19
Obere Grenzfrequenz (-3dB/4Ohm):

M23

Messwerte​

Dauerleistung an 8 Ohm (1kHz):271 W
Dauerleistung an 4 Ohm (1kHz):411 W
Impulsleistung an 4 Ohm (1kHz):533 W
Klirrfaktor bei 50mW (1kHz):0.0039 %
Klirrfaktor bei 5W (1kHz):0.0012 %
Klirrfaktor bei Pmax -1dB (1kHz):0.5 %
Intermodulation bei 50mW (nach DIN):0.0008 %
Intermodulation bei 5W (nach DIN):0.00059 %
Rauschabstand ab Hochpegeleingang bei 50mW (1kHz):90 dB
Dämpfungsfaktor an 4 Ohm bei 63Hz/1kHz/14kHz:108/107/78
Obere Grenzfrequenz (-3dB/4Ohm):47 kHz
Eingangspegelsteller:ja
Leistungsanzeige:nein
Leistungsaufnahme Leerlauf:22.8 W
Gemessen bei einer Netzspannung von:226 V
 

curiousland

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We have no plans to make other versions of the AHB2. Our biggest challenge is keeping up with the demand for the AHB2.
What a disappointment! I use 2 AHB2 with HPA4, each running single channel only since bridge mode would double impedance and reduce Damping Factor significantly (also factored in the impedance of 10' Benchmark speaker cables) based on your worksheet.

Higher power version of AHB2 with improved Damping Factor is strongly desirable. DF of amps from like Accuphase are now about 1000.
 

curiousland

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We have no plans to make other versions of the AHB2. Our biggest challenge is keeping up with the demand for the AHB2.
Also I'd respectfully ask that the challenge you mentioned shall be a production department issue and your department is responsible for R&D of new products and there was no product from Benchmarks for many years now, why?
 

restorer-john

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Also I'd respectfully ask that the challenge you mentioned shall be a production department issue and your department is responsible for R&D of new products and there was no product from Benchmarks for many years now, why?

When you have an excellent selling, ultra high performance product which people are clamouring for, why mess with the formula? The AHB2 is now essentially a classic. (I didn't want to use the word 'benchmark'...)
 

HarmonicTHD

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What a disappointment! I use 2 AHB2 with HPA4, each running single channel only since bridge mode would double impedance and reduce Damping Factor significantly (also factored in the impedance of 10' Benchmark speaker cables) based on your worksheet.

Higher power version of AHB2 with improved Damping Factor is strongly desirable. DF of amps from like Accuphase are now about 1000.
Why would you think that damping factors of 1000 are even relevant?

See here
 

RichB

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When you have an excellent selling, ultra high performance product which people are clamouring for, why mess with the formula? The AHB2 is now essentially a classic. (I didn't want to use the word 'benchmark'...)
Speaking for "mature" individuals, I like the concept of the AHB2 being both SOTA and a classic :p

- Rich
 

misterdog

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^^ and sounding damm fine, even though it has no sound.
Straight wire with gain, and all that.
 

curiousland

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Wh

Why would you think that damping factors of 1000 are even relevant?

See here
Thanks for the link, even though obviously lots of people have different opinion about this. If not, why so many well-known/high-end brands all specify their DF just like SNR etc. and brag about their R&D efforts to improve that after already worked on amp technology for 50+ years? Are they all on a different planet?
 

HarmonicTHD

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Thanks for the link, even though obviously lots of people have different opinion about this. If not, why so many well-known/high-end brands all specify their DF just like SNR etc. and brag about their R&D efforts to improve that after already worked on amp technology for 50+ years? Are they all on a different planet?
Simple answer they want to get your money.

A bit longer one: One can consider the problem of electronics on sound as solved with modern amps, dacs etc. So what do companies do to differentiate something which strictly speaking has essentially become a commodity? Yes. They make stuff up with which they can create the appearance of being better although they are factually not. Or the „improvement“ (eg damping factor, slew rate, high rez etc) is irrelevant. All that, so they can charge higher prices and protect their profits. Because in this technical field not everyone can know all the details and marketing can make up stories. This site has the goal to lift the veil of such practices so people can make better buying decisions if they choose to.
 

curiousland

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When you have an excellent selling, ultra high performance product which people are clamouring for, why mess with the formula? The AHB2 is now essentially a classic. (I didn't want to use the word 'benchmark'...)

AHB2 took the advantage of THX technology, is good/great but far from perfect. It's a shame not to expand further based on that THX.

From business perspective, esp. for tech-related companies, not continue developing/improving new product is a path to death and competition will soon catch up. Is it just to make $$ and forgot about the original passion to audio technology?

From consumer point of view, I'd think twice of buying products from such companies because it means no future upgrade path and investment will be obsolete, forget about "classic".
 

GXAlan

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We have no plans to make other versions of the AHB2. Our biggest challenge is keeping up with the demand for the AHB2.

One day it would great to have a champagne colored one :)
 

pablolie

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AHB2 took the advantage of THX technology, is good/great but far from perfect. It's a shame not to expand further based on that THX.

From business perspective, esp. for tech-related companies, not continue developing/improving new product is a path to death and competition will soon catch up. Is it just to make $$ and forgot about the original passion to audio technology?

From consumer point of view, I'd think twice of buying products from such companies because it means no future upgrade path and investment will be obsolete, forget about "classic".

Things like the AHB2, Purifi or Ncore push things well beyond the threshold of our hearing... to me innovation going forward is about how to integrate packages. Even I have stopped buying separates. In any case, surely there will be innovation, but in general I think it will be around function integration.

I'd rather see a Benchmark DAC4-D that has integrated bass management with a sub out, and supports Dirac.
 

Kal Rubinson

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AHB2 took the advantage of THX technology, is good/great but far from perfect. It's a shame not to expand further based on that THX.
Agreed. I would welcome it if they could come up with a verifiably superior amp.
From consumer point of view, I'd think twice of buying products from such companies because it means no future upgrade path and investment will be obsolete, forget about "classic".
Why? My "upgrade path" is always open-ended and is never restricted to products from companies whose products I have already used.
 
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