Benchmark AHB2 Review (Updated Measurements)

[digitalfrost]

Well, looks like i don't have to worry about adapters for this amp at all, because in Holland it's seemingly forged from unobtanium!,
official sales price here 4370 Euro's.
aka, completely out of my budget.

It seems they raised the price, the german distributor also has it listed for 4.4k now

Benchmark AHB2 Endverstärker schwarz

Benchmark AHB2 Stereo Endverstärker - Studioqualität bei Axmann kaufen Der AHB2 hat einen SNR über 130dB. Ausführung in Schwarz

www.silberkabel.net

 

[DSJR]

The only way I might possibly be enticed away from my stacked AHB2s would be by a single compact, lightweight multichannel amp of comparable (or better) performance. Purely for aesthetics.

Forgive me here, but I'm stunned that nobody seems to criticise those speakers for such terribly bad design that allows a 1.7 ohm or whatever impedance dip which almost comes across as a badge of honour. Smacks of arrogance in the design to me, but I suspect that's the high end for you

I'd stay with the Benchmark amps regardless and like my fifty year old power amp here, I'd trust them to be still good many years from now and heirlooms almost to be passed down assuming there's offspring that may appreciate them...

 

[AdrianusG]

It seems they raised the price, the german distributor also has it listed for 4.4k now

Benchmark AHB2 Endverstärker schwarz

Benchmark AHB2 Stereo Endverstärker - Studioqualität bei Axmann kaufen Der AHB2 hat einen SNR über 130dB. Ausführung in Schwarz

www.silberkabel.net

That's then almost 1000 Euro's on top of the US price right?

 

[HarmonicTHD]

That's then almost 1000 Euro's on top of the US price right?

Thomann lists them for ca 3700

 

[AdrianusG]

Thomann lists them for ca 3700

Not quite,

Thomann.de and Thomann.nl , both 3999 Euro

Anyways, still way out of my budget, so pass!

 

[EdW]

Forgive me here, but I'm stunned that nobody seems to criticise those speakers for such terribly bad design that allows a 1.7 ohm or whatever impedance dip which almost comes across as a badge of honour. Smacks of arrogance in the design to me, but I suspect that's the high end for you

I'd stay with the Benchmark amps regardless and like my fifty year old power amp here, I'd trust them to be still good many years from now and heirlooms almost to be passed down assuming there's offspring that may appreciate them...

I wasn’t going to say that - I just thought it! When 2 very high quality amps, give markedly different bass performances just when driving one particular make of speakers but both amps work extremely well with top notch, relatively low Z speakers like the KEF BLADE 2, then you have to ask what is strange about these speakers. @pogo in post #314 suggested a sensitivity to damping factor. Whether this is the case or not the speaker designer should have evaluated them under different drive conditions and ensured crossovers etc. were reasonably insensitive to variations in drive conditions.
(I hadn’t heard of this speaker make before but that is probably a reflection on my lack of knowledge)

 

[Kal Rubinson]

I wasn’t going to say that - I just thought it! When 2 very high quality amps, give markedly different bass performances just when driving one particular make of speakers but both amps work extremely well with top notch, relatively low Z speakers like the KEF BLADE 2, then you have to ask what is strange about these speakers. @pogo in post #314 suggested a sensitivity to damping factor. Whether this is the case or not the speaker designer should have evaluated them under different drive conditions and ensured crossovers etc. were reasonably insensitive to variations in drive conditions.
(I hadn’t heard of this speaker make before but that is probably a reflection on my lack of knowledge)

This behavior seems typical for this company:

https://www.stereophile.com/content/estelon-xb-diamond-mk2-loudspeaker-measurements

https://www.stereophile.com/content/estelon-forza-loudspeaker-measurements

 

[HarmonicTHD]

Not quite,

Thomann.de and Thomann.nl , both 3999 Euro

Anyways, still way out of my budget, so pass!

Ah difference is VAT.

 

[HarmonicTHD]

This behavior seems typical for this company:

https://www.stereophile.com/content/estelon-xb-diamond-mk2-loudspeaker-measurements

https://www.stereophile.com/content/estelon-forza-loudspeaker-measurements

It’s a feature not a bug.

 

[RichB]

It’s a feature not a bug.

The price is $149,000 to $163,000 a pair.

Estelon Forza loudspeaker Specifications

Sidebar 1: Specifications Description: Four-way, sealed-box loudspeaker. Drive-units: 1" (25mm) Accuton inverted diamond dome tweeter, 8" (203mm) CELL aluminum sandwich midwoofer, 7" (178mm) CELL ceramic membrane midrange, 2 11" (279.5mm) woofers. Crossover frequencies: N/A. Frequency range...

www.stereophile.com

So, finding an amp that can drive these with and EDPR of 1 Ohm may not have a financial constraint.

- Rich

 

[HarmonicTHD]

The price is $149,000 to $16w,000 a pair.

Estelon Forza loudspeaker Specifications

Sidebar 1: Specifications Description: Four-way, sealed-box loudspeaker. Drive-units: 1" (25mm) Accuton inverted diamond dome tweeter, 8" (203mm) CELL aluminum sandwich midwoofer, 7" (178mm) CELL ceramic membrane midrange, 2 11" (279.5mm) woofers. Crossover frequencies: N/A. Frequency range...

www.stereophile.com

So, finding an amp that can drive these with and EDPR of 1 Ohm may not have a financial constraint.

- Rich

Sure. But when does price says something about engineering quality ;-)

 

[DSJR]

Well I'm sorry. I don't give a flying hoot about the stupid-high costs, but to me it's BAD design at any price and wearing this terrible load as a badge of honour just doesn't rub with me any more! I appreciate @Kal Rubinson may feel differently, but I'd have regarded these speakers as all but undriveable and flawed myself and moved on (that would have done it and maybe not in a good way with the audiophile fraternity)

Heck, we had all this 1 ohm nonsense in the 80's with Apogee and Magnaplanar panels needing a humungous Krell, Levinson and so on at least to drive them which almost kicked off the need for amps which automatically doubled their power into halving the impedance load (not sure the Threshold and other US/Canadian amps were quite to this level?). In this age of top notch DSP actives which no doubt would easily out perform these things for a fraction of the price (if not looking so 'nice'), does Stereophile really need to promote such confections/jewellery?

[edit] - They don't even have a properly sorted low bass performance with the peak at 60Hz, accepting the rise below 400Hz is Stereophile's odd and uncorrected measuring technique - I wonder how uncouth rock music would sound on them, rather than the more civilised gentle tones of chamber music?

Apologies for ranting off topic here. I'm just really pleased the AHB2's in bridged mode seem able to drive a 3 - 4 ohm load happily and without complaint

 

[Ajax]

Exactly my point. The AHB2 is a great amplifier but from a few years back. But SOTA class D amps will inexorably displace the very best class A or AB amps for power audio amplification. The performance strides made by Bruno Putzeys in his latest design give us lower cost, lower dissipation, lower THD, much lower IMD. These last few years have seen the greatest jump in amplifier performance since the invention of negative feedback. Come to think of though Bruno’s designs rely greatly on novel and ingenious ways to implement feedback. Formidable engineering indeed.

I agree.

When one considers that many "high end" manufacturers still demand US$20,000 + for their amplifiers, the AHB2 at only $3,000 for SOTA performance represented great value.

However, today for less than US$1,200 you can have 200 watts into 8 ohms with extraordinary transparency with the excellent Hypex NCX500 or Purifi models from several manufacturers (Apollon, Buckeye, BoXem, Audiophonics, etc).

Thanks to the efforts of Bruno and Amir, Audio is in a great place with a SOTA front end - streamer, DAC and Amp - now available for less than US$1,500.... just add speakers.

Apollon NCx500ST Stereo Amplifier Review

This is a review and detailed measurements of the Apollon NCx500ST stereo class D amplifier based on Hypex NCOREx NCx500 modules. It was kindly drop shipped from the member and costs 1,090.00€ (US $1,168) with standard opamp. While the case is stamped aluminum, it is a heavily customized one...

www.audiosciencereview.com

Buckeye 3 Channel Purifi Amplifier Review (2nd)

This is a second review of the Buckeye 3-Channel Purifi based balanced class D amplifier. First sample had an issue with its binding posts increasing distortion. It costs US US $1,595. Typical of Buckeye amplifiers, focus on what is inside rather the case which is utilitarian. An indicator...

www.audiosciencereview.com

 

[Gringoaudio1]

Well I'm sorry. I don't give a flying hoot about the stupid-high costs, but to me it's BAD design at any price and wearing this terrible load as a badge of honour just doesn't rub with me any more! I appreciate @Kal Rubinson may feel differently, but I'd have regarded these speakers as all but undriveable and flawed myself and moved on (that would have done it and maybe not in a good way with the audiophile fraternity)

Heck, we had all this 1 ohm nonsense in the 80's with Apogee and Magnaplanar panels needing a humungous Krell, Levinson and so on at least to drive them which almost kicked off the need for amps which automatically doubled their power into halving the impedance load (not sure the Threshold and other US/Canadian amps were quite to this level?). In this age of top notch DSP actives which no doubt would easily out perform these things for a fraction of the price (if not looking so 'nice'), does Stereophile really need to promote such confections/jewellery?

[edit] - They don't even have a properly sorted low bass performance with the peak at 60Hz, accepting the rise below 400Hz is Stereophile's odd and uncorrected measuring technique - I wonder how uncouth rock music would sound on them, rather than the more civilised gentle tones of chamber music?

View attachment 339913

Apologies for ranting off topic here. I'm just really pleased the AHB2's in bridged mode seem able to drive a 3 - 4 ohm load happily and without complaint

Agree. Any speaker with a load that difficult was designed by an incompetent.

 

[gene_stl]

I recently attempted to assist someone in the task of getting a pair of Infinity Kappas running. These were a famous and probably good sounding if properly driven large floor stander from the eighties I think. He sent me the crossover circuit diagram and they were a five way system. They also had a rearward firing tweeter that had it's own crossover section which was all in parallel configuration. A six way parallel crossover. The speakers were famous for being a difficult load for amplifiers to drive. I suggested that he unwire the rearward firing tweeter and biamp using the removeable link that was available between the multiple wooofers and the rest of the system. This would have made the high frequency array "merely" a four way which most amplifiers probably could have driven. But one can only imagine the gyrating impedances of a six way crossover.
In the end the guy decided to not trouble himself with these old classic speakers which probably would have sounded great tri or quad amped. But there were also some blown drivers that needed replacement or refurbishment.

You shouldn't need a welder to drive a pair of loudspeakers. Although the new Gallium Nitride output devices that are starting to show up in Class D amps are used for just that purpose. And powerful electric motor controls where they save a lot of wasted energy.

 

[denydog]

The low level pop, or click noise from the speakers, when activating the power off button on my bridged ABH2s, is gone! I was experiencing the same noise as some others in this thread.

I moved my amps today, closer to each speaker, and replaced the 12 ft Bluejeans 10 GA cables with 4 ft versions of the same. The real difference was installing speakON connectors, replacing locking bannana's at the amp end. The slight pop, I call it a click sound from the tweeter/mid, is gone. I still hear the relays in the amp a second or two after hitting the button, when the lights go out, but that's it.

There were 6 other people in this thread by my count reporting a similar noise on power down. Might be interesting to know if they are using the bannana or speakON connections.

 

[tmtomh]

I recently attempted to assist someone in the task of getting a pair of Infinity Kappas running. These were a famous and probably good souding if properly driven large floor stander from the eighties I think. He sent me the crossover circuit diagram and they were a five way system. They also had a rearward firing tweeter that had it's own crossover section which was all in parallel configuration. A six way parallel crossover. The speakers were famous for being a difficult load for amplifiers to drive. I suggested that he unwire the rearward firing tweeter and biamp using the removeable link that was available between the multiple wooofers and the rest of the system. This would have made the high frequency array "merely" a four way which most amplifiers probably could have driven. But one can only imagine the gyrating impedances of a six way crossover.
In the end the guy decided to not trouble himself with these old classic speakers which probably would have sounded great tri or quad amped. But there were also some blown drivers that needed replacement or refurbishment.

You shouldn't need a welder to drive a pair of loudspeakers. Although the new Gallium Nitride output devices that are starting to show up in Class D amps are used for just that purpose. And powerful electric motor controls where they save a lot of wasted energy.

I recently inherited a pair of those Kappa 9s. They have a "Normal/Extended" switch on the back, where the Normal setting adds a resistor into the bass part of the crossover network. That solves the problem of them dipping to 0.8 ohms(!) around 70Hz in Extended mode. The cost is slightly lower bass response - but with 2x 12" woofers per speaker, crossed to the midwoofer starting at 80Hz, in my experience they still produce plenty of bass in that configuration.

I believe that leaves the only sub 2-ohm frequency at 10kHz. No doubt disconnecting that rear-facing tweeter could solve that. But on the other hand I wonder how much energy is up there anyway with most music, meaning I don't know how much current that impedance dip way up there would draw from an amp anyway.

My father (from whom I inherited the speakers) drove them with a 60lb Adcom GFA-5800 spec'd at 400wpc into 4 ohms - an arc welder indeed. But I drove them with an amp based on the original Purifi module and they did just fine. I cranked them to about 92dB at 3 meters and everything appeared to be functioning fine and dandy.

So yes, they are a tough load, and they are a kooky design that can be very cool but probably shouldn't be replicated by anyone else... ever. But with good modern Class D designs available nowadays, I don't think one needs quite such an exceptional or unique amplifier to drive them as one might have needed back in the '80s when they came out.

 

[Endibol]

Well, looks like i don't have to worry about adapters for this amp at all, because in Holland it's seemingly forged from unobtanium!,
official sales price here 4370 Euro's.
aka, completely out of my budget.

Living in the Netherlands you can order it on line in Germany for 3,999 euro including shipment.

 

[Endibol]

Thomann lists them for ca 3700

3,999 euro right now, they seem to have increased the price since January 1st.

 

[Nicolas]

The low level pop, or click noise from the speakers, when activating the power off button on my bridged ABH2s, is gone! I was experiencing the same noise as some others in this thread.

I moved my amps today, closer to each speaker, and replaced the 12 ft Bluejeans 10 GA cables with 4 ft versions of the same. The real difference was installing speakON connectors, replacing locking bannana's at the amp end. The slight pop, I call it a click sound from the tweeter/mid, is gone. I still hear the relays in the amp a second or two after hitting the button, when the lights go out, but that's it.

There were 6 other people in this thread by my count reporting a similar noise on power down. Might be interesting to know if they are using the bannana or speakON connections.

FWIW i use 3ft cables with speakON connectors and indeed never heard that pop noise.