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Review and Measurements of Benchmark AHB2 Amp

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Could you describe the setup, the process, the way data was gathered, and controls? This is a remarkable claim.
Sure, amps with similar architecture and good measured performance can be indistinguishable.
I am also searching for the reason for observed differences, as others have stated, in so many words.

The systems are described here:
https://www.audioholics.com/amplifier-reviews/ati-at4002

Game Room: Revel M20's, Oppo UDP-205, Oppo HA-1 (Preamp) sourced my Roon (network)
Living Room: Revel Salon2's, Oppo UPD-205 Emotiva XMC-1 (Stereo Reference mode) sourced by Roon (USB-DAC)

My systems have changed as of late:
  • Sold the HA-1 for the game room. Going Oppo UHD Direct (thanks to Roon)
  • Added an LA-4 for a two channel mode: Oppo UDP-205 -> LA4 -> Salon2's.
In the game room, the switch between the AHB2 and AT522NC in less-than 20 seconds.
Directly comparing these amps in my systems, I find it unremarkable that completely different architectures (which also measure differently) sound differently.

Are you in the Boston area? If so, perhaps I could demonstrate.

- Rich
 

SIY

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Sure, amps with similar architecture and good measured performance can be indistinguishable.
I would agree with the latter, but the former has never been demonstrated.

Unfortunately (or fortunately, depending on your POV!), I'm about 2500 miles away from Boston, otherwise I would be glad to help you set up a well-controlled comparison.
 
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I would agree with the latter, but the former has never been demonstrated.

Unfortunately (or fortunately, depending on your POV!), I'm about 2500 miles away from Boston, otherwise I would be glad to help you set up a well-controlled comparison.
I'd say unfortunately :)

I'll leave it at this, if you think an amp could improve your system, this one should be on your list.
To judge for yourself, costs about $100 in shipping but only $50 if you keep it.

You don't see much B-Stock at Benchmark ;)

- Rich
 

SIY

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Oh, I'd be very happy with a Benchmark. I have a more conventional AB amp on my test bench at the moment which looks pretty similar in performance and costs about the same. I'd be happy with that as well. My wife would prefer something more invisible.
 

Daverz

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It's not a good idea to put an audio device on the same circuit as an AC, fridge, microwave, etc. Too much potential for line issues, as you're finding. The 3B probably has more than adequate power cap capacity and can take the dip in power. This is the sort of stuff one can expect when you get to that level/price of product.
I think they made some compromises in the B-60 power supply for the form factor. It certainly wasn't cheap at the time, IIRC around $1500 with the phono option circa 2001.

That said, it's a great little integrated. I'd still recommend one if you can find a good price on it.
 
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GrimSurfer

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I think they made some compromises in the B-60 power supply for the form factor. It certainly wasn't cheap at the time, IIRC around $1500 with the phono option circa 2001.

That said, it's a great little integrated. I'd still recommend one if you can find a good price on it.
It's $3000 now, which I find to be a little excessive. I had a discussion with the manager at Bryston about this but they seem to feel justified doubling their price in about 10 years. As this would equate to a year on year price increase of 7%, perhaps they should be running my investment portfolio too.

Form factor might have something to do with it. The B60 is a heavy integrated, so they're not appearing to be scrimping on materials. As a potential customer, I'd prefer functionality, cooling, power supply issues coming ahead of form factor.

Value wise, the B60 is pushing boundaries. Very good quality but at a price that's too high by about $600-800 if you ask me. I think Simaudio/Moons are better value, especially in the $2000-3000 range.

If you're Benchmark and offer the performance they do, price plays less of a role. But everyone has a budget, and it is still and issue for those shopping for 100W and below.
 
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GrimSurfer

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It's still a good product but Bryston needs to grip this up if they want to attract new customers.

FWIW, I hope that trade wars heat up. Why? Because it will bring manufacturers back down to the levels of their home markets.
 
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Oh, I'd be very happy with a Benchmark. I have a more conventional AB amp on my test bench at the moment which looks pretty similar in performance and costs about the same. I'd be happy with that as well. My wife would prefer something more invisible.
Some pictures of the AHB2 on top of the AT522NC are attached. The AT522NC is only 10" deep.
I read the specs, but in person, it is amazingly compact.

The AHB2 idles at 20 watts verses the AT522NC which idles at 38 watts.

My main system moved from 2 x AT6002 and an AT6006 to 4 AHB2's. As a result,
  • the idle power went down from approximately 300 watts to 80 watts
  • weight was decreased by 262 lbs.,
  • fans are no longer needed, and
  • all transformer hum eliminated.
I was able to fund most of the upgrade by selling the ATI's.

The front 3 channels Salon2's and Voice2 are passively bi-amped. Horrors!

Playing Lorde Royals at +15 (low gain mode) is required to clip the amp driving the Salon2 3 x 8" bass drivers.
This is louder than I care to listen these days. I have not clipped movies at reference levels, even though, that is theoretically possible.
It's a really nice feature to have clip-indicators on each channel.
There is always the option to mono-block, but thus-far, I have not found the need.

- Rich
 

Attachments

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Assembled a pair of nCore monoblocks with high hopes a few years back. Was utterly disappointed, sounded thin/anemic to me, now sold. Replaced with a Norma Revo IPA-140 integrated amplifier, couldn't be happier.

Been trying to understand why the nCore's disappointed. Only numbers I can find that may/may not explain my experience are the ones below.

Hypex nCore nc400 / Norma Revo IPA-140

Cont. Power @ 8 Ohm (W) ~ 80 -100 / 140

Slew Rate (V/us) ? / 175

Peak Current (Amp) 25 / 150

So, a Class-H amp next maybe.
I agree. Drums just didnt sound like drums, and I have no idea why. I still have the amps as they will be useful for subwoofers.

The AHB2 looks like end game for most. What stops me is that I would need 2, as my speakers are 80-81db sensitive. I reach clipping with my current power amp with 150WPC. Maybe one day
 

Sal1950

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What does Bruno have to say about this?:
BP: Well, if the amplifier is truly great that’s absolutely right. Sonic signatures are what you get when you approach the same ideal from different angles. There are a few distortion mechanisms conspicuously missing in Class D, mostly those related to the input stage of a Class A(B) solid-state amplifier and nonlinear capacitances. Those are also missing in valve [tube] amplifiers so it’s quite common for people to notice that a Class D amplifier is somehow reminiscent of valve amplification in terms of “sweetness” for want of a better word.

Oh brother, here we go. Now he compares them to tube amps and "sweetness"
Maybe he's right, we all know tube amps can sound different and the reasoning why.
Maybe they sound different but inferior technically just like the valves?
 

restorer-john

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As a result,
  • the idle power went down from approximately 300 watts to 80 watts
  • weight was decreased by 262 lbs.,
  • fans are no longer needed, and
  • all transformer hum eliminated.
I was able to fund most of the upgrade by selling the ATI's.
This is an example of a worthwhile improvement. None of those points are insignificant.
 

Sal1950

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This is an example of a worthwhile improvement. None of those points are insignificant.
Absolutely, But none supportive of sonic differences.
Except the fans and transformer change, you should notice the lack of noise. ;)
 
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BP: Well, if the amplifier is truly great that’s absolutely right. Sonic signatures are what you get when you approach the same ideal from different angles. There are a few distortion mechanisms conspicuously missing in Class D, mostly those related to the input stage of a Class A(B) solid-state amplifier and nonlinear capacitances. Those are also missing in valve [tube] amplifiers so it’s quite common for people to notice that a Class D amplifier is somehow reminiscent of valve amplification in terms of “sweetness” for want of a better word.

Oh brother, here we go. Now he compares them to tube amps and "sweetness"
Maybe he's right, we all know tube amps can sound different and the reasoning why.
Maybe they sound different but inferior technically just like the valves?
Maybe amp designers think their amps sound better than other amps because they worked so hard on them.
IDK, but most seem to have opinions about it.

- Rich
 
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Absolutely, But none supportive of sonic differences.
Except the fans and transformer change, you should notice the lack of noise. ;)
Is it fair to ask if you have listened to these amps?

- Rich
 

Sal1950

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Maybe amp designers think their amps sound better than other amps because they worked so hard on them.
Absolutely, what else would you expect.

IDK, but most seem to have opinions about it.
As do ten's of thousands of keyboard warriors around the world.
But I have yet to see any of them publish data from a verified scientifically controlled test that supports their claims.
I hear exactly the same claims make for $10,000 power cords.

Is it fair to ask if you have listened to these amps?
Sure it's fair to ask.
To be honest I don't remember. for sure. Pretty sure I heard the Benchmark at the Tampa audio show a few months back.
But that would be a sighted listening totally without any controls.
Which would make any impressions valueless.
 
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I agree. Drums just didnt sound like drums, and I have no idea why. I still have the amps as they will be useful for subwoofers.

The AHB2 looks like end game for most. What stops me is that I would need 2, as my speakers are 80-81db sensitive. I reach clipping with my current power amp with 150WPC. Maybe one day
This really trips me out. I am using a NAD M22 and it sounds fantastic. Drums sound amazing - if well recorded. In fact, Art Blakey's drum work on "Bluesianna Triangle" is mesmerizing. I listen to some Indian classical music that features tabla and mridangam (whose sounds I am intimately familiar with) and the timbre is dead on. In general timbres on the M22 are very realistic (this coming from a tube aficionado). I don't understand why others have such a wildly different experience. The only thing that makes sense to me is that something upstream is at work to change the sound -or the speakers are very difficult to drive (mine aren't.) For streaming, I just have a Marantz HD-DAC1 into a passive preamp into the NAD. Listening to some African acoustic music just now streaming from Spotify, and Bruno is right. It sounds closer to my tube amps than any of the SS gear that I have used.

In any case, I have an ABH2 on order, and so will find out for myself. The NAD sounds so neutral that I can't quite image how the Benchmark will improve on it. This is going to be interesting;)
 
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In the video world, display technology keeps improving but each new technology introduces a new type of artifact.
Sample-and-hold which affects motion, spectrum bandwidth which leads to metamerism, etc.
New display, new flaws, but overall much improved.

It seems reasonable to that audio amplifier may also experience this phenomenon.
For this not to be the case, we would have to have developed perfect and complete amplifier tests.

Do amplifier test measure dynamic performance or infer it using steady state resistive loads?
Does distortion always remain low at all frequencies when driving difficult reactive loads?
Are amplifiers always linear or do they have momentary sags?
Perhaps, amplifier measurements are complete, but I'm not so sure.

For me, measurements are the anti into the game.
I would never consider an buying an amplifier that measures poorly.

The reason I own 5 AHB2's is because a friend brought one over and we listened to it.
I was convinced that they were no match (at reasonable listening levels) for my ATI6000's.
The ATI's are very nice amplifiers. and size, heat, weight, and sound quality were all factors, but It was sound quality that pushed me over the edge.

I realize that I could edit this post and replace amplifiers with $10,000 cables.
However for cables, I do think we have full and complete measurements. ;)

- Rich
 
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