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Review and Measurements of Benchmark AHB2 Amp

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Still doesn't have THX on the front for £3k. Say what get me 30 of these for £1k off the back end of lorry and we have a deal. Otherwise £3k I keep my Behringer and Crown amps. I know find out what makes it so good and take those parts and I can stick them in the Behringer and Crown amps.
I actually had a crown XLS. The ICEpower monoblocks sounded a bit better than the Crown. The benchmark beats the pants off the Class D and the Crown.

It's funny how a bunch of you are all of a sudden throwing shade all over this amp. I mean, there's nothing wrong being happy with what you have, but why bother wasting your time attacking another product that gets universal praise?

Attacking scam products I understand, but this is just silly.
 

Pjetrof

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? ? ? Under controlled blind double testing, the dac and amp playing ........ you all know the score.
the audible differences are inaudible!

The reason to buy that Dac or this Amplifier should never have to do with how the amp or dac sound.

So the “NO” was correct, but to short. Anyway thats my personal opinion.
And everybody’s opinion I respect, i will not argue or discuss.

So for me yes electronics I can’t hear diffrences! But maybe others can. Lucky me the choice would become very difficult then
which amp to choose or which dac....... they all sound different. There are thousands different dacs and amps i would end up
in a nut house!
 

RichB

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? ? ? Under controlled blind double testing, the dac and amp playing ........ you all know the score.
the audible differences are inaudible!

The reason to buy that Dac or this Amplifier should never have to do with how the amp or dac sound.

So the “NO” was correct, but to short. Anyway thats my personal opinion.
And everybody’s opinion I respect, i will not argue or discuss.

So for me yes electronics I can’t hear diffrences! But maybe others can. Lucky me the choice would become very difficult then
which amp to choose or which dac....... they all sound different. There are thousands different dacs and amps i would end up
in a nut house!
Please stay out of the nut house, this is not a life and death matter.

- Rich
 

DonH56

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? ? ? Under controlled blind double testing, the dac and amp playing ........ you all know the score.
the audible differences are inaudible!

The reason to buy that Dac or this Amplifier should never have to do with how the amp or dac sound.

So the “NO” was correct, but to short. Anyway thats my personal opinion.
And everybody’s opinion I respect, i will not argue or discuss.

So for me yes electronics I can’t hear diffrences! But maybe others can. Lucky me the choice would become very difficult then
which amp to choose or which dac....... they all sound different. There are thousands different dacs and amps i would end up
in a nut house!
I have little experience with the plethora of DACs available so have no comment on those. I suspect audible differences among them are more about noise isolation than performance differences.

For amplifiers, yes, I can pick out amplifiers in a DBT but it depends upon the amplifiers and speakers. There is more to it than just distortion; there is noise floor and in some cases frequency response variations that are readily discernable. The biggest differences in my experience occur when comparing tube amplifiers to SS. With sufficiently low noise floor and operated well below clipping I find it hard if not impossible to distinguish among competent SS amps, and in many cases even among tube amps. But use a speaker with a widely varying load and the higher output of tube amps causes frequency variations rather easy to detect, and the same can be true with some SS amplifiers.

IME/IMO/etc. - Don
 
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? ? ? Under controlled blind double testing, the dac and amp playing ........ you all know the score.
the audible differences are inaudible!

The reason to buy that Dac or this Amplifier should never have to do with how the amp or dac sound.

So the “NO” was correct, but to short. Anyway thats my personal opinion.
And everybody’s opinion I respect, i will not argue or discuss.

So for me yes electronics I can’t hear diffrences! But maybe others can. Lucky me the choice would become very difficult then
which amp to choose or which dac....... they all sound different. There are thousands different dacs and amps i would end up
in a nut house!
Do not forget the complex loads speakers present. The interaction of the amp and speaker is far from linear and different amps will interact with the same pair of speakers differently. In addition, many amps measure differently. So let's not pretend that all amps sound the same, because they don't.
 

josh358

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To build this level of quality and safety features for a lot less would be a challenge. Unlike many audio companies Benchmark seems to price somewhat fairly. I'm in Europe so it's too hard to buy, too expensive and too difficult to get maintenance. On our side of the water, I went for dual Pro-Ject Stereo Box DS2 vertically bi-amped. The result is good, but one has to be careful not to put too merciless a DAC/pre-amp combination in front as the Hypex UdC102 amps are not providing a soft landing (as my NAD C372 would). Still working to find the right match (might be the RME ADI-2 DAC FS, the traditional NAD C165BEE in front of a Musical Fidelity V90 is very good but is very big in my space). The Benchmark amp sounds similarly merciless.

Benchmark DAC/pre-amp and Benchmark amp might be a tough long-term listen. Has anyone got the pair running together? If so what are your impressions?
I've found too that the AHB2 is merciless.

I've only heard the DAC and amp together at a show. As I recall, it was a very cold, pristine sound.
 

josh358

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Some people can't handle the truth. :cool:
I wouldn't have a problem with it if there wasn't so much HF distortion in some recordings! I go back and forth between my AHB2 and my A21 on the tweeters -- the AHB being more detailed and neutral and the A21 more forgiving.

Another thing that creeped me out -- someone wrote that he compared the Benchmark DAC and another DAC in the studio, and that the Benchmark sucked all the ambiance out. The only thing I can think (assuming he was correct) is that there was something wrong with the DAC chip and it was truncating the LSB's. But I've heard the same phenomenon in some Class D amps -- they sound very clean, and then you realize that the space has gone missing!
 

Kal Rubinson

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I wouldn't have a problem with it if there wasn't so much HF distortion in some recordings! I go back and forth between my AHB2 and my A21 on the tweeters -- the AHB being more detailed and neutral and the A21 more forgiving.
OK, I am with you there but I was taking exception to your characterization "a very cold, pristine sound" since that is descriptive of coloration and not of an unwanted accuracy.
 

josh358

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OK, I am with you there but I was taking exception to your characterization "a very cold, pristine sound" since that is descriptive of coloration and not of an unwanted accuracy.
OK, I see your point. Truth is, I wasn't sure whether it was accurate or not. I just gave my subjective impression without meaning to judge it.
 

josh358

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How do you know it's in the recordings and not your speakers? I don't hear a lot of HF issues in the studio. Over compression (loudness war) yes, but that's another issue.

http://seanolive.blogspot.com/2009/10/audios-circle-of-confusion.html
Because I've listened on headphones to make sure, and it's still there. Not to mention that not all recordings have it. I don't think I've heard it on rock recordings (other forms of distortion, yes), but I hear it on classical recordings all the time, along with other issues like screechy violins.
 
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I wouldn't have a problem with it if there wasn't so much HF distortion in some recordings! I go back and forth between my AHB2 and my A21 on the tweeters -- the AHB being more detailed and neutral and the A21 more forgiving.

Another thing that creeped me out -- someone wrote that he compared the Benchmark DAC and another DAC in the studio, and that the Benchmark sucked all the ambiance out. The only thing I can think (assuming he was correct) is that there was something wrong with the DAC chip and it was truncating the LSB's. But I've heard the same phenomenon in some Class D amps -- they sound very clean, and then you realize that the space has gone missing!
I'd be surprised if the benchmark DAC3 is that bad in terms of "space" removal. All the reviews with subjective listening tests are glowing. My guess is there was something wrong with the setup or the DAC. One negative 'review' out of dozens, with the rest being positive doesn't dissuade me. The only thing keeping me from purchasing the DAC3 is my bank account
 
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josh358

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I'd be surprised if the benchmark DAC3 is that bad in terms of "space" removal. All the reviews with subjective listening tests are glowing. My guess is there was something wrong with the setup or three DAC. One negative 'review' out of dozens, with the rest being positive doesn't dissuade me. The only thing keeping me from purchasing the DAC3 is my bank account
What interested me about the review is that it was made in the studio by pros, so I don't think this is audiophile imagination. But I agree -- I don't see how a properly functioning and connected DAC3 fed the right bits could do that, and I agree that it would probably show up on the tests.
 

PaulD

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What interested me about the review is that it was made in the studio by pros, so I don't think this is audiophile imagination. But I agree -- I don't see how a properly functioning and connected DAC3 fed the right bits could do that, and I agree that it would probably show up on the tests.
Ummm, I have worked in many studios wth "pros" for a couple of decades - they are as biased by sighted listening as any human. I have heard some of the most outrageous nonsense from pros in terms of audio quality (e.g., you can ONLY get a decent vocal recording with an original U47, etc etc etc). I read that report and took it with the large grain of salt it deserved. Uncontrolled = biased. Even Bob Katz (mastering engineer) was fooled when he did not-level match DACs properly to within 0.1dB, he could not explain the sound difference until he checked the levels and tested again...
 
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josh358

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Ummm, I have worked in many studios wth "pros" for a couple of decades - they are as biased by signed listening as any human. I have heard some of the most outrageous nonsense from pros in terms of audio quality (e.g., you can ONLY get a decent vocal recording with an original U47, etc etc etc). I read that report and took it with the large grain of salt it deserved. Uncontrolled = biased. Even Bob Katz (mastering engineer) was fooled when he did not-level match DACs properly to within 0.1dB, he could not explain the sound difference until he checked the levels and tested again...
But then Bob Katz did check the levels. In any case, I didn't get the sense from the post we read that this effect was at all subtle -- it was IIRC presented in rather dramatic terms -- but of course you're right that pros can make mistakes as a consequence of uncontrolled listening.

I still find it troubling remark, one that has to be filed in the yet-to-be-decided folder. Certainly I can't rule it out on an engineering basis. I doubt that further speculation would do anything to alter that.
 

tmtomh

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Just as the early phases of the Covid pandemic saw some medical professionals who are not researchers downplay the seriousness of the virus and some lab researchers who are not epidemiologists engage in outrageously irresponsible speculation about how it was mainly spread, so too is the audio profession filled with studio engineers and mastering pros who are better than most of us will ever be at producing great-sounding recordings... and don't know the first thing about digital sampling theory or what does and does not impact the performance of the gear they use.

Technical expertise in most science and tech fields is as narrow as it is deep. Barry Diament has done wonderful recording and mastering work for decades. And he has also written that CDs produced by certain pressing plants sound truer to his masters than others, and has written that he and his wife did a hearing test and he could hear to 28kHz and she could hear to 22kHz. Countless audio engineers claim to hear instant, consistent, night-and-day differences between high-res and redbook playback of otherwise identical musical content, when we know that's not true. They similarly claim that high-bitrate AAC or mp3 sounds like garbage when we know that's so much of an overstatement as to simply be untrue (differences between high-bitrate lossy and PCM lossless are subtle and often very difficult if not impossible to reliably detect). The list goes on and on. Professional status and skill in the production of music has surprisingly little to do with the kind of technical knowledge we tend to discuss here, and the granting of any special credence to the views of such professionals in terms of the fidelity of sound equipment is just an Appeal to Authority fallacy. Usually subjectivists employ it, but we objectivists are not above doing so as well when a prominent studio pro happens to take a position we agree with (for example anti-MQA).

Finally, I think @PaulD 's example of Bob Katz getting fooled by a 0.1dB volume difference is important to note (regardless of what happened afterwards) - humans can be surprisingly sensitive to very small volume differences, and what makes it even more tricky, based on what I've read, is that when the difference gets less than about 1dB, we often still hear a difference but it doesn't necessarily register as a volume difference. It registers as some other kind of sound quality difference. That can lead us down all kinds of false paths.
 

josh358

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Just as the early phases of the Covid pandemic saw some medical professionals who are not researchers downplay the seriousness of the virus and some lab researchers who are not epidemiologists engage in outrageously irresponsible speculation about how it was mainly spread, so too is the audio profession filled with studio engineers and mastering pros who are better than most of us will ever be at producing great-sounding recordings... and don't know the first thing about digital sampling theory or what does and does not impact the performance of the gear they use.

Technical expertise in most science and tech fields is as narrow as it is deep. Barry Diament has done wonderful recording and mastering work for decades. And he has also written that CDs produced by certain pressing plants sound truer to his masters than others, and has written that he and his wife did a hearing test and he could hear to 28kHz and she could hear to 22kHz. Countless audio engineers claim to hear instant, consistent, night-and-day differences between high-res and redbook playback of otherwise identical musical content, when we know that's not true. They similarly claim that high-bitrate AAC or mp3 sounds like garbage when we know that's so much of an overstatement as to simply be untrue (differences between high-bitrate lossy and PCM lossless are subtle and often very difficult if not impossible to reliably detect). The list goes on and on. Professional status and skill in the production of music has surprisingly little to do with the kind of technical knowledge we tend to discuss here, and the granting of any special credence to the views of such professionals in terms of the fidelity of sound equipment is just an Appeal to Authority fallacy. Usually subjectivists employ it, but we objectivists are not above doing so as well when a prominent studio pro happens to take a position we agree with (for example anti-MQA).

Finally, I think @PaulD 's example of Bob Katz getting fooled by a 0.1dB volume difference is important to note (regardless of what happened afterwards) - humans can be surprisingly sensitive to very small volume differences, and what makes it even more tricky, based on what I've read, is that when the difference gets less than about 1dB, we often still hear a difference but it doesn't necessarily register as a volume difference. It registers as some other kind of sound quality difference. That can lead us down all kinds of false paths.
Yep, I think it's well known (at least I hope it is) that listening comparisons have to be level matched with 0.1 dB.

By the way, for what it's worth (or was), CD's from different pressing plants can sound different, or could at any rate in the days when jitter wasn't well understood. Last I heard, which was decades ago, Sony was aware of and studying the problem, which they traced to variations in pit geometry.

It seems to me that most of the perceived difference between Red Book and high sample rate CD's is a consequence of mastering decisions rather than the sampling rate. However, we do know that the difference between 44.1 and higher sampling rates can be ABX'd.

Now here's an interesting one that surprised me no end when I learned of it -- people with impaired hearing, or who are listening to poor loudspeakers, can be more sensitive to compression artifacts because frequency response irregularities throw off the psychoacoustic masking.

Why do I mention all of this? Well, partly because it's interesting, but also because it's a reminder that we should never fall into the trap of assuming that we fully understand a situation. I agree with you regarding MQA and other points. However, not all evaluations are technical; good ears are not to be underestimated. And I would not call what I said an appeal to authority. To begin with, I was not trying to convince anyone, but pointing to my own assessment. But beyond that -- is the word of a doctor on a medical issue worth no more than the word of a barber? The Fallacy of Authority is commonly misunderstood. In my case, I took the word of a (fellow) professional more seriously than I would have taken the word of an audiophile. And while my work is on the technical end, I have a good deal of respect for the perceptions of recording and mastering engineers.

Which is to say that I continue to file this under the heading of "troubling but undetermined" rather than "audiophile nonsense" or "demonstrated in a controlled prospective study with 100,000 participants."

I mean, I probably would have laughed at the claim that CD pressings sound different, too . . .
 
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