Benchmark AHB2 Review (Updated Measurements)

[Owl]

I bought my Benchmark amp for all the same reason most people bought there's, and it has proven to be worth every penny. Longevity and serviceability, if necessary, being the main points. As far as class D reliability is concerned, it looks like the module kits that are sold have a higher failure rate than the plate amps assembled by the manufacture, mainly Hypex.

 

[D700]

I believe the Bluesound Powernode is UcD. Likewise I think the NAD C700 (which should be a Powernode with screen). And that vintage looking NAD C3050. NAD just loves using UcD...

My Marantz HD-AMP1 uses UCD as do a few of their other lower priced amps

 

[kadajawi]

By comparison with the later amps like NCORE they seem old-fashioned, but they are a bargain and work well enough.

NAD is using UcD on lower tier amps, mid and higher tier ones get nCore. For the top of the line they use Purifi. Having had the Powernode I'd say they ought to drop UcD for anything but the lowest tier... I much prefer the Audiolab 6000A over it, so selling an amp twice as expensive as the Audiolab and still use the UcD isn't that appealing.

 

[pablolie]

NAD is using UcD on lower tier amps, mid and higher tier ones get nCore. For the top of the line they use Purifi. Having had the Powernode I'd say they ought to drop UcD for anything but the lowest tier... I much prefer the Audiolab 6000A over it, so selling an amp twice as expensive as the Audiolab and still use the UcD isn't that appealing.

Nothing wrong with using UcD: when implemented capably clearly the specs indicate that hearing a difference between all these great amps that have been discussed is either impossible or incredibly hard. Somebody has to convince me you can hear a difference once you go into beyond 90dB or so SINAD...

I am not at all disputing that there's a benefit in versatility -if you have the room and speakers- to the immense power the Purifi and Ncore modules offer, but for SQ alone, hey. Just know your particular use case and there are many choices out there.

I know I had a NAD M22v1 and Benchmark AHB2 side by side for 2 months, and the audible difference was absolutely zero-none-nada. And I'll add to that that at the SPLs I listen to in my room, the humbled UcD is also virtually undistinguishable from an SQ perspective. But as mentioned, the wattage may not be sufficient depending on use case.

I also respect those who care about where something is assembled, but there are 2 sides to that argument... one side can easily claim the fact we (foolishly, imo) handed over most manufacturing to China and other lower labor cost markets results in quality there being better (many industries show that), but then I also want to support those who want to bring manufacturing expertise back to the USA. And as has been stated, many of the modules and chips will invariably be produced in places other than the USA for the time being.

 

[D700]

I bought my Benchmark amp for all the same reason most people bought there's, and it has proven to be worth every penny. Longevity and serviceability, if necessary, being the main points. As far as class D reliability is concerned, it looks like the module kits that are sold have a higher failure rate than the plate amps assembled by the manufacture, mainly Hypex.

For anyone fiddling with math, consider my plight. 11 years ago I bought a “Deluxe AVR” from a Major Brand with historic rep, dropped about $2000. It gave good performance for about 5 years then required mail off for service for a warning light, worked about another year before 1 channel stopped working, so i dumped it, figured I’d damaged it in a move or shipping.

My next and current amp was $1k, less ambitious, stereo only and it leaves me needing more power, so I’m back looking

I am not poor but not rich enough to afford buying things twice. If I’d known of AHB2 I’d have been money ahead, not to mention it probably has great resale value where my other 2 …don’t.

YMMV

 

[Mnyb]

Notice: DSPman was deemed to be Returning (Previously Banned for his 5th or 6th reincarnation) Mike from Mivera audio. His account is closed and every single post that he made with this new Shadow Account has been deleted.

​

Ok one of the usual trolls , can not also all/most responses to his trolling ber gone , that would clean up this review tread

 

[Mnyb]

On topic what about the slight load dependency can it be audible in som extreme case ? with real world speakers ?

As frequency response errors are audible and 0.0000x distorsion is not ?

The noise performance will ofcourse also be flawless in this amp, so it will be quiet.

if this amp matched my economy and power needs it would be a top contender .

 

[fredoamigo]

I bought my Benchmark amp for all the same reason most people bought there's, and it has proven to be worth every penny. Longevity and serviceability, if necessary, being the main points. As far as class D reliability is concerned, it looks like the module kits that are sold have a higher failure rate than the plate amps assembled by the manufacture, mainly Hypex.

As far as reliability is concerned, I don't think we have enough experience yet (with this amp and the Hypex) to say that it's reliable, because there are rarely any hour counters on amps.
We all know that the main enemy of reliability is heat, but other factors can alter reliability, such as the use of poor-quality components or heteroclite designs that try to reinvent the wheel...
In my opinion, we can say that an amp is reliable from a minimum of 10 hours of use per week for 10 years without worry.

 

[Rottmannash]

The UcDs are for sure the worst, but there are still issues with the NCores. Purifis aren't used much vs Hypex. But I'll put it this way - there's a reason most active speakers use Pascal or ICEPower, despite Hypex performing better.

Perhaps because they're much cheaper to purchase? Older tech vs newer tech.

 

[Kal Rubinson]

On topic what about the slight load dependency can it be audible in som extreme case ? with real world speakers ?

I suspect so. For the past couple of years, I've had both the Benchmark and the NAD C298 and used them almost interchangeably, depending on circumstance. Recently, I used the NAD to review a loudspeaker which I generally enjoyed save for its notably skimpy bass performance <100Hz despite having a 10" woofer in a floor standing enclosure. I did not suspect the NAD but, to be sure, I switched over to the Benchmark and, to my surprise, the bass was restored to a great degree.

After I completed my writing, John Atkinson measured the loudspeaker and found that the speaker's EDPR (equivalent peak dissipation resistance) "drops below 1 ohm between 61Hz and 71Hz, with a minimum EPDR of 0.85 ohms at 65Hz." He says that it represents "a very demanding load for the partnering amplifier."

See full story at: https://www.stereophile.com/content/estelon-aura-loudspeaker

 

[Rottmannash]

As far as reliability is concerned, I don't think we have enough experience yet (with this amp and the Hypex) to say that it's reliable, because there are rarely any hour counters on amps.
We all know that the main enemy of reliability is heat, but other factors can alter reliability, such as the use of poor-quality components or heteroclite designs that try to reinvent the wheel...
In my opinion, we can say that an amp is reliable from a minimum of 10 hours of use per week for 10 years without worry.

...learned a new word today-"heteroclite"

 

[fredoamigo]

...learned a new word today-"heteroclite"

Synonyms: variegated, hybrid, quirky, aberrant, absurd, bizarre, extravagant, eccentric, preposterous

 

[kadajawi]

While

Nothing wrong with using UcD: when implemented capably clearly the specs indicate that hearing a difference between all these great amps that have been discussed is either impossible or incredibly hard. Somebody has to convince me you can hear a difference once you go into beyond 90dB or so SINAD...

The Powernode sounded harsh, aggressive, scratchy at higher volume. The Audiolab, which is rated at only 2x50 W (vs 2x80 W), at such SPL, did not have any such issue. Neither does the NAD C298, for example. On another system we noticed that with an IcePower-based XTZ metal songs were sounding unpleasant. We thought that was due to the songs being poorly produced. Switching to a C298 (so Purifi again) that was gone.

 

[pablolie]

Well, one Powernode module was measured here as around 90dB, the other significantly lower. One was recommended, the other not. So that may explain your impressions. I don't know the Audiolab, but I harbor no doubts the C298 measures favorably.

 

[DavidEdwinAston]

To clarify. My Quad Artera pre- amp and Quad Platinum amplifiers, are end game for me, as long as they don't "break".

I should have added that if they do "break", I would first find out if Quad could "mend" them!

 

[AdamG]

Ok one of the usual trolls , can not also all/most responses to his trolling ber gone , that would clean up this review tread

It gets really dicey when we delete members posts without good reason. Plus there are so many it would further destroy the flow of the conversation. Not saying no. But it would be a big undertaking and chances of pissing off senior members. I would rather ask the members who are involved to delete their own posts that no longer make sense.

 

[enricoclaudio]

It gets really dicey when we delete members posts without good reason. Plus there are so many it would further destroy the flow of the conversation. Not saying no. But it would be a big undertaking and chances of pissing off senior members. I would rather ask the members who are involved to delete their own posts that no longer make sense.

Honestly, I would keep all his posts so the community sees them as an example of how you should not behave in this community and what would happen if you do so!!

@AdamG thanks for all you do for keeping us on track !!

 

[AdamG]

@AdamG thanks for all you do for keeping us on track !!

You are welcome but it’s not just me. Brad is the senior Moderator and he does much more to keep this ship headed in the right direction than I do. I would crumble under the weight of trying to do this job without Brads guidance and support. I am fortunate to work with two incredibly professional people who set high standards themselves. I just try to keep up…

 

[DonH56]

On topic what about the slight load dependency can it be audible in som extreme case ? with real world speakers ?

As frequency response errors are audible and 0.0000x distorsion is not ?

The noise performance will ofcourse also be flawless in this amp, so it will be quiet.

if this amp matched my economy and power needs it would be a top contender .

This thread includes some simulations of amp/speaker interactions. As noted in the thread, one of the amps modeled was Benchmark's AHB2.

Amplifier Output Impedance (Damping Factor) and Speakers

This is a reprint of an article written ca. 2011-2012. I've been meaning to rewrite and update it, but Life and Work keeps getting in the way, so I am reposting the original as-is. Take it for what it's worth, an introductory take on one of the potential causes for differences in sound among...

www.audiosciencereview.com

The AHB2's output impedance is plenty low enough for any speaker I know.

 

[DonH56]

I suspect so. For the past couple of years, I've had both the Benchmark and the NAD C298 and used them almost interchangeably, depending on circumstance. Recently, I used the NAD to review a loudspeaker which I generally enjoyed save for its notably skimpy bass performance <100Hz despite having a 10" woofer in a floor standing enclosure. I did not suspect the NAD but, to be sure, I switched over to the Benchmark and, to my surprise, the bass was restored to a great degree.

After I completed my writing, John Atkinson measured the loudspeaker and found that the speaker's EDPR (equivalent peak dissipation resistance) "drops below 1 ohm between 61Hz and 71Hz, with a minimum EPDR of 0.85 ohms at 65Hz." He says that it represents "a very demanding load for the partnering amplifier."

See full story at: https://www.stereophile.com/content/estelon-aura-loudspeaker

This is an excellent response that highlights several key points:

1. Not all amplifiers sound alike driving all loads (speakers);
2. Output impedance does matter (among other things); and,
3. Speakers can be more demanding than we think.

It also obviates any claims that the Benchmark cannot handle low impedances...