Benchmark AHB2 Review (Updated Measurements)

[Purité Audio]

Well this just goes to show that paying too much attention to the Measurement page is misguided! Take a look at the Conclusions at the end of the write up:

"Words fail to express the satisfaction I derived listening to music through this expensive Audio Note integrated amplifier. I've got nothing bad to say about it—except for the air thing, if you care about that. I detected no (other) anomalies, artifacts, sonic peculiarities, or outright shortcomings. The Tonmeister, together with the Audio Note SUT I auditioned it with, took what I hear from my vinyl collection and made it better, portraying each performance as a singular, unique event occurring at a particular time and place, its secrets revealed.

If there's a better integrated amplifier in the world than the Audio Note Meishu Phono 300B Tonmeister, I haven't heard it yet."

I've not bothered to read the whole review as it's not an amp I have any interested in, but if it was, surely those comments are more likely to encourage a serious demo than a few PC screen plots showing what a microphone picks up?

Had I concerned myself with the Measurements page of the Avantgarde Uno's 2002 review, perhaps I wouldn't have bothered to read the extremely detailed and accurate write-up by Robert Deutsch that prompted my purchase, and I'd have missed out on years of musical entertainment listening to those great speakers.

The ‘subjective’ text is just that just a puff piece, ,didn’t two of the Stereophile ‘reviewers’ used to import Audio Note into the US?
Measurements on the other hand don’t lie.
What I find interesting is that you rejected a fine measuring amplifier. and eventually settled on a fine measuring amplifier, which I believe would be absolutely indistinguishable if compared level matched and unsighted.
Keith

 

[RichB]

I guess on any of the hundreds or thousands of subjective audiophile sites...

I guess on any of the hundreds or thousands of subjective audiophile sites...

A new thread here would be fine: AHB2 - poor damping factor, overrated, and too expensive

- Rich

 

[blueone]

Yikes.

Is there a thread somewhere, where this might be considered informative?

- Rich

No. He's completely lost, and is using useless subjective comments from silly reviews to justify a position he is emotionally attached to.

Edit: the only reasons I ever read Stereophile was to read JA's measurements sections, and his occasional commentary articles about how he made recordings.

 

[Platypus20]

A new thread here would be fine: AHB2 - poor damping factor, overrated, and too expensive

- Rich

Now you tell me, after I bought 4 of them !!!

 

[RichB]

Now you tell me, after I bought 4 of them !!!

I bought 5

There is no issue driving the Salon2 woofers.

- Rich

 

[blueone]

I bought 5

There is no issue driving the Salon2 woofers.

- Rich

I hope you have a special "personal articles" insurance policy to cover your system. No homeowner's policy I've ever seen will cover that $80K-$100K you've invested (at retail replacement cost)...

 

[Martini]

I bought 5

There is no issue driving the Salon2 woofers.

- Rich

I’ve only bought 2, but I’m a mere peasant. They are driving a pair of F328be and sound fantastic, not “dull” in the least.

 

[Geert]

I bought 5

There is no issue driving the Salon2 woofers.

Such low impedance speakers on an amp with abysmal damping factor, poor you

 

[Hear Here]

Measurements on the other hand don’t lie.

Thanks Keith - But with no ears, they can't judge the joy or otherwise that listeners with ears are searching for.

What I find interesting is that you rejected a fine measuring amplifier. and eventually settled on a fine measuring amplifier, which I believe would be absolutely indistinguishable if compared level matched and unsighted.

Are you talking about the AHB2 and the M33? If so, there was a significant difference in the sound between these 2 well-measuring amps.

In fact I was looking for a replacement (solid state) amp for my earlier SETs. These were based on 845 and PX-25 tubes, but I'd also had amps using 300B and 6C33C. It was no easy exercise, but all decisions were taken on how the amps actually sounded. Not all equally good measuring amps sound the same as I described above. Peter

 

[AdamG]

Thanks Keith - But with no ears, they can't judge the joy or otherwise that listeners with ears are searching for.


Are you talking about the AHB2 and the M33? If so, there was a significant difference in the sound between these 2 well-measuring amps.

In fact I was looking for a replacement (solid state) amp for my earlier SETs. These were based on 845 and PX-25 tubes, but I'd also had amps using 300B and 6C33C. It was no easy exercise, but all decisions were taken on how the amps actually sounded. Not all equally good measuring amps sound the same as I described above. Peter

You do realize where you are right? Audio Science. All your Subjective opinions and awakenings are mostly irrelevant to our Members. If we want to read this regurgitated advertisement lingo we can go to any number of Subjective Review Sites and YouTube blathers. You have been here a few years so you know exactly what you are doing with your attempts to drag members into your Troll bait posts. It’s not working but you obviously won’t stop on your own so we are stepping in to halt your nonsense. Take a few weeks off and contemplate if you honestly want to discuss engineering and science. If you don’t please go find a better home.

 

[Kal Rubinson]

Perhaps not worth taking too seriously, but AHB2 was a finalist but not a winner in Stereophile's 2016 "Best of" awards in 2016, whereas in 2020 they chose the M33 as their Amplification Component of the Year and their overall Component of the Year and also their Editors' Choice - a hat trick that I believe no other product has ever achieved. Thank you Kal - see -

I don't any way to draw conclusions from this. Very few of the other editors have had any contact with the AHB2.

The point I made earlier about reviewers' caveats regarding the AHB2 is typified by the section under Listening in the City on Page 2 of Kal's review -

Where is the caveat?

 

[denydog]

I kind of enjoy Here Here' s contributions to this thread. It has been a little dull lately, but nothing like some good humor to perk it up. I've been laughing.

 

[Julf]

Thanks Keith - But with no ears, they can't judge the joy or otherwise that listeners with ears are searching for.

And you believe you can judge it by reading some audiophile magazine review?

 

[livinon2wheels]

"More than enough".I guess I neeed to rephrase the question...does the damping factor go up or down? Conventional thinking would say that it goes down with a lower load impedance, but that applies to conventional (class a or a/b) amps. I don't know how class D circuitry handles differing load impedances with respect to damping factor. Anyone care to weigh in on this?

 

[pablolie]

..
Are you talking about the AHB2 and the M33? If so, there was a significant difference in the sound between these 2 well-measuring amps.
..

I completely dispute that. I spent 3 weeks with a NAD M22 and the Benchmark AHB2, agonizingly so. There was zero difference in sound, and miniscule measured differences in Stereophile tests.

 

[Julf]

To livinon2wheels (that seems to have managed to write his/her question inside the quotes attributing it to me) - the damping factor is defined as the ratio of load impedance to output impedance, so it is no way dependent on the amplifier operating class. It is exactly the same for class A, A/B, D (or C, for that matter).

 

[cornoalto]

A small addition to the topic of damping factor and load stability of the AHB2:

My speakers show this impedance:

Minimum 0.6 Ohm, sic! (18 pieces Peerles TC9FD18-08 wired in parallel to line array from 115 Hz upwards.)
More infos and measurements:
https://www.aktives-hoeren.de/viewtopic.php?t=6508&start=75


The thin curve shows the actual damping factor of the AHB2 in relation to my speakers:

Even above 3 khz where the damping factor goes down under 10 the sound is exceptionally sweet and clear.

Since the efficiency is 97 dB, a maximum of 5 watts are needed per channel. Most of the time just1 Watt.
The amplifier runs without getting particularly warm and sounds extremely clean, stable and fine.

Because of the low impedance I previously used a Mcintosh MC2250 with an autoformer output at 1 ohm.
Compared to the AHB2, the Mc sounds so undetailed, smeared in complex areas and with fewer timbres,
less stable and tires more quickly.


A technician from Benchmark told me:


"The "1-Ohm" limit is really a limit on current. If the amplifier exceeds an output current of 29 amps,
the over-current protection will trip. At 0.6 Ohms, this will occur at a peak voltage of 17.4 V, or 34.8 Vpp,
or 12.3 Vrms. 12.3 Vrms into 0.6 Ohms is 252W.
This means that the current protection in the AHB2 should trip at about 252 W into 0.6 Ohms.
This is well over the required 0.8 watts.
At 252 W into 0.6 Ohms, the amplifier would reach thermal shutdown if run continuously at this level.
At 10 watts, the amplifier will not go into thermal shutdown."

I don't know of any other amplifier that is so load stable and at the same time sounds so pure.
Can`t be happier with Benchmark AHB2.

 

[Julf]

Compared to the AHB2, the Mc sounds so undetailed, smeared in complex areas and with fewer timbres,
less stable and tires more quickly.

I am curious, how many fewer timbres, how did you count them, how long did it take for it to get tired, and how quickly did it recover?

 

[SIY]

tires more quickly

Vitamins might help.

 

[cornoalto]

Sorry, but I don't find your question particularly funny and I can't take it entirely seriously either.
A timbre describes the overtone spectrum of a tone and the time course of the occurrence of
the overtones.
The timbre of a violin note changes as the bow is bowed closer to the bridge
or the bow pressure changes. A clarinet has many more overtones in the low register than in the high register.
A cymbal sounds different in piano than in forte.
When an amplifier adds distortion to the signal it may be that certain overtones are more obscured or, in the case of phase problems, the transient process
no longer corresponds to the natural transient process. Then it can occour, that those subtle changes in timbre can no longer be perceived (masking effect).
I'm a bit surprised that I have to explain something like this here.
By less timbres of the Mc, I meant that the AHB2 dissolves such subtile changes of a recorded sound, for example from nasal to dark, more finely. As professional klassical musican I think, that I am able to hear this.
Getting tired: Recognizing of a Instrument with its specific overtone spectrum is a mental achievement.
Known overtone spectra are compared with what is heard and the brain tries an assignment to a well-known voice/instrument. In addition,
the transient process is analyzed over time.
The less distortion an amplifier has, the easier it is to do this and the longer you can listen without getting tired. This is simply science:
Perceptual psychology and physics. You can also say stressed instead of tired. Did you never listen to a bad measuring amp for a longer time and making such a experience?
But my point isn't about any timbres, I just wanted to point out that the AHB2 in my experience simply works wonderfully even with a load of 0.6 to 1.2 ohms.
I wonder a little bit why you didn't address that at all.