New Benchmark AHB2 - High-resolution amplifier

[haraldo]

Benchmark is now in the Power Amplifier Business too

AHB2 - Power Amplifier | Benchmark Media

Preliminary specifications:

Power Output
• 100 W/channel into 8 Ohms, both channels driven
• 170 W/channel into 4 Ohms, both channels driven
• 340 W Bridged Mono into 8 Ohms


Dynamic Range
• 130 dB A-weighted
• 125 dB 20 Hz - 80 kHz


THD
• <-118 dB relative to full output at any output level below clip, stereo, 1 kHz
• <-118 dB relative to full output at any output level below clip, bridged mono, 1 kHz
• 0.00013%


THD+N
• < -108 dB relative to full output, 1 kHz
• 0.0004%


Frequency Response
• Better than 0.1 Hz to 200 kHz, +0/-3 dB

 

[Irvrobinson]

That is a really, um, unusual product. SpeakON outputs... my favorite connector, but I can think of only one home speaker that used them (the Linkwitz Orion), so almost everyone will be using the binding posts, which look sort of cheap. No single-ended inputs, not that I'd use them, but oddly market limiting. And then there's all of that talk about handling wide dynamic range, but this is a 100/170w/ch amp... sort of weak for anyone touting dynamic range as a selling point. Hmmm... I'm not sure what to make of this amp.

 

[cpp]

I guess we won't know, until someone actually hears it....

 

[mtrycrafts]

As Irv mentioned, what good is all that 130 dB range? Where will it be used? Which speaker? Which recording breaks the 96 dB CD limit? Who has a room that has the noise floor at the threshold of hearing?
And, I just love this comment: The frequency response of the AHB2 extends beyond 200 kHz, to deliver the ultrasonic detail and fast transients captured by high-resolution recordings
Oh, well.

 

[Irvrobinson]

And, I just love this comment: The frequency response of the AHB2 extends beyond 200 kHz, to deliver the ultrasonic detail and fast transients captured by high-resolution recordings
Oh, well.

I noticed that too, but to be fair bigger companies than Benchmark have touted super-wide bandwidth as an advantage before, like Harman-Kardon. I'm guessing this thing will pass a perfect 10KHz square wave, though I've never seen any evidence that being able to perform that trick makes an amp sound better. Frankly, I find the low power rating more curious in the context of the dynamic range discussion.

I'm wondering what price Benchmark is going to ask for this amp? I use one of their DAC1-HDRs as a pre-amp/DAC, and it is a wonderful product, once you get over the weird form-factor, but it isn't cheap by any means. If this amp is $1000 it might be interesting, especially if the crossover distortion avoidance circuitry really makes a difference, but if it's priced at $2000 or more I think it'll be a tough sell.

 

[RichB]

There are some pretty serious heat sinks on that amp.
Maybe it is a biased amp similar to Pass labs.

- Rich

 

[Irvrobinson]

There are some pretty serious heat sinks on that amp.
Maybe it is a biased amp similar to Pass labs.

- Rich

Well, take into account how small the main chassis of that amp is. It's only 8.5" wide, and probably about as deep. In bridged mono-block mode it's rated to put out 340w, which means it's probably drawing at least 600 watts of AC from the wall. The difference between the audio output and that AC mains power is going to be heating up that little chassis right quick. Compare this little Benchmark amp to, for example, my ATI AT602, which is only rated at 90w/ch into 4 ohms, but is twice the size, and you can see why some serious heatsinks are needed on the Benchmark amp. The ATI makes this Benchmark amp look like a midget, and the Benchmark is rated for about twice the power in bridged mode.

 

[PENG]

I think I am going to agree with Gene on the sqaure wave thing mainly base of the reason he cited. In fact, same idea for the first watt, double down kind of talks because those things are no longer a concern given today's technology.

For example, I need good SQ for the first 0.2 watt, but from what I can see in lab test results, most $2K class AB amp manufacturers must have figure out how to design and implement negative feedback or other techniques to keep THD+N (T means total and total means total..)so low that you really can't tell/hear the differences between such low noise, HD, IMD, and COD. Yes I am talking about within the audible bandwidth, so don't even go there. That's just my 2 cents based on technical facts and data. Bottom line, I do want to own a Pass lab, Boulder, AR, Krell or ML but I know I do not need any of them. I do need a Bryston, Halo and a couple of ATI though for sure. As for Benchmark, I pass, want one of their DACs though.

 

[AcuDefTechGuy]

That is a really, um, unusual product. SpeakON outputs... my favorite connector, but I can think of only one home speaker that used them (the Linkwitz Orion), so almost everyone will be using the binding posts, which look sort of cheap. No single-ended inputs, not that I'd use them, but oddly market limiting. And then there's all of that talk about handling wide dynamic range, but this is a 100/170w/ch amp... sort of weak for anyone touting dynamic range as a selling point. Hmmm... I'm not sure what to make of this amp.

I love Speakon connectors too. Linkwitz really tries to make his speakers "different" from the masses with Speakon & quad-amp active speakers.

But really, who's going to buy a 100 WPC amp?

 

[jinjuku]

That is a really, um, unusual product. SpeakON outputs... my favorite connector, but I can think of only one home speaker that used them (the Linkwitz Orion), so almost everyone will be using the binding posts, which look sort of cheap. No single-ended inputs, not that I'd use them, but oddly market limiting. And then there's all of that talk about handling wide dynamic range, but this is a 100/170w/ch amp... sort of weak for anyone touting dynamic range as a selling point. Hmmm... I'm not sure what to make of this amp.

I guess it would be speakon's on one end and spade, banana, bare copper on the other. Not too odd plus there is the traditional binding post for the people that want $5K in speaker cables.

My second question: Who makes this for them?

 

[Irvrobinson]

My second question: Who makes this for them?

Since they have the capability to stuff their own boards with a very expensive machine, I'd bet heavily they build it themselves.

 

[jinjuku]

Since they have the capability to stuff their own boards with a very expensive machine, I'd bet heavily they build it themselves.

So did Lexicon....

 

[Irvrobinson]

So did Lexicon....

How much do you wanna bet?

 

[macddmac]

I saw them at RMAF this weekend.. Would have payed more attention if I was aware of this thread

 

[jinjuku]

How much do you wanna bet?

Not my point. When I see some wonder product from a company that typically doesn't roll in that space it's reasonable to wonder. I've had a Benchmark DAC-1 apart and less than thrilled with the build quality. Which is why I would take a pass on their amp if done in house.

 

[Irvrobinson]

Not my point. When I see some wonder product from a company that typically doesn't roll in that space it's reasonable to wonder. I've had a Benchmark DAC-1 apart and less than thrilled with the build quality. Which is why I would take a pass on their amp if done in house.

Yes, I know, you and I have been through this question before.

 

[mtrycrafts]

I noticed that too, but to be fair bigger companies than Benchmark have touted super-wide bandwidth as an advantage before, like Harman-Kardon. I'm guessing this thing will pass a perfect 10KHz square wave, though I've never seen any evidence that being able to perform that trick makes an amp sound better. Frankly, I find the low power rating more curious in the context of the dynamic range discussion.

I'm wondering what price Benchmark is going to ask for this amp? I use one of their DAC1-HDRs as a pre-amp/DAC, and it is a wonderful product, once you get over the weird form-factor, but it isn't cheap by any means. If this amp is $1000 it might be interesting, especially if the crossover distortion avoidance circuitry really makes a difference, but if it's priced at $2000 or more I think it'll be a tough sell.

Then to follow this up, while others claim such wide bandwidth, do they also claim the ultrasonic detail benefits that has no evidence of audibility, or just have it without such claims?
Yes, The Audio Critic tested that dac, just wonderful product specs and yes, expensive.

 

[mtrycrafts]

..That's just my 2 cents based on technical facts and data. ....

Well then, it is worth a lot more than 2 cents.

 

[John Siau]

Thanks for the questions and comments about our new AHB2 power amplifier. I will be at the AES 2013 show in NYC and would be happy to discuss the new technologies incorporated into this new amplifier. For those of you who will not be attending the AES show, I will attempt to outline the engineering decisions that went into the AHB2.

It was my goal to create a power amplifier that matched the performance of the DAC2 D/A converter. After all, the performance of the D/A converter is only useful if it can be delivered by the downstream power amplifier.

In many ways, the AHB2 is a radical departure from conventional class AB amplifier design:

1) Low gain (9 dB) - allows +22 dBu input at amplifier clip - essential for low noise
2) Patented feed-forward error correction - virtually eliminates crossover distortion
3) Feed-forward design makes bias currents unnecessary, and non-critical - class B operation is possible with very low distortion
4) Multiple output stages run in parallel to eliminate crossover distortion - one output stage is active while another is in the crossover region
5) Class AB output stage uses very low bias current
6) Due to low bias currents, idle power consumption is only 20 W
7) Feed-forward design makes class H or G operation possible - no rise in distortion at class H or G switch point
8) Class H (or G) rail switching at a 1/3 power threshold
9) Tightly regulated power supply
10) High-bandwidth control loop on switch-mode power supply responds to amplifier loading over the entire audio band, and at ultrasonic frequencies
11) Amplifier does not rely on capacitive energy storage
12) Switch-mode power supply eliminates AC line magnetic interference to levels that are not possible with a linear power supply
13) >200 kHz bandwidth to achieve excellent inter-channel phase at 20 kHz.
14) < 0.1 Hz low frequency cutoff to minimize low-frequency phase shift
15) Feed-forward design improves damping factor

The AHB2 design was optimized for low distortion and low noise. It was not optimized for the highest possible efficiency that can be achieved with this new topology. Nevertheless the AHB2 is much more efficient than a conventional class AB design. Peak power does not vary with AC line voltage (due to regulated supply). Power drawn on one channel does not influence the power available from the other channel.

The AHB2 is a linear amplifier, it is not a switcher. For this reason, it produces very little out-of-band noise. A-weighted noise is only 2 dB less than noise measured over an 80 kHz bandwidth. This was an important design goal because ultrasonic noise can be folded into the audio band by non-linearities in speaker transducers.

If you have more questions, talk to me at AES, or post questions here.

 

[Irvrobinson]

Hi John, that is a very interesting design. Some of the questions are already in this thread, like does Benchmark manufacture the amp or was the manufacturing outsourced? Do you have a target price range yet?

Another question... which market is this amp primarily targeted for? Home audio or pro studio?