Review and Measurements of Benchmark AHB2 Amp

[VeerK]

I am surprised that there has not been more takers as there were with headphone amps. Hopefully this will resolve in the future.

Have to agree with you here, with the success of the 789, I’d have thought there might be some rumbling of manufacturers thinking of offering something in the speaker amp segment. For those interested in fully digital setups, near field, etc where the power of the AHB2 isn’t going to be fully utilized, it would be amazing to see some competing offerings. Fingers crossed for the (near) future.

 

[JimB]

...
The numbers are ludicrous, as a speaker enthusiast, I need this or another power amp using this tech in my setup. I’ve been designing my own speakers for a while now, half tempted to grab 3 of these for a full digital crossover and DSP implementation, if only my wife wouldn’t kill me.

You would not be the first! Is there any defense in, "But honey, it's what all the serious audiophiles use these days - just listen..."

Or, if you can make it stick, "But these are the last amps we will ever need - honest..."

 

[Sal1950]

Or, if you can make it stick, "But these are the last amps we will ever need - honest..."

They just might be the last components you buy of any type, ever. LOL

 

[Laserjock]

Received my ABH2 yesterday after placing an order on 11.1. Nice looking unit, hooked it up to some Insignia NSB-2111 bookshelf speakers for initial testing and all seems in order.

Nice,
Not knowing how the $70 (?) Insignia’s sound, but seems like a leap in amplification for a “cheap” 90dB speaker?

is that your final or you have something more in mind for the AHB2?

 

[cookiefactory]

Nice,
Not knowing how the $70 (?) Insignia’s sound, but seems like a leap in amplification for a “cheap” 90dB speaker?

is that your final or you have something more in mind for the AHB2?

Heh that would be some component price balance

Nah I have a pair of Energy Veritas 2.4i which serve as my main speakers. I also just picked up a couple of bookshelf speakers - Ascend Sierra 2EX and Buchardt S400. Currently comparing them head to head with the intent of keeping one. The ABH2 will end up driving either the Energy or whichever bookshelf I keep.

 

[Spocko]

Heh that would be some component price balance

Nah I have a pair of Energy Veritas 2.4i which serve as my main speakers. I also just picked up a couple of bookshelf speakers - Ascend Sierra 2EX and Buchardt S400. Currently comparing them head to head with the intent of keeping one. The ABH2 will end up driving either the Energy or whichever bookshelf I keep.

Definitely looking forward to see if you notice any differences between the ABH2 and "lesser amps" on both the 2EX (with their highly resolving RAAL tweeters) and S400 (another transparent well made speaker that's been getting rave RAVE reviews). What sources will you be using as the front end for the ABH2?

 

[cookiefactory]

Definitely looking forward to see if you notice any differences between the ABH2 and "lesser amps" on both the 2EX (with their highly resolving RAAL tweeters) and S400 (another transparent well made speaker that's been getting rave RAVE reviews). What sources will you be using as the front end for the ABH2?

Thanks, I've been using a Panasonic SA-XR57 to drive the 2EX and S400 thus far (my father's - I actually sent *my* SA-XR57 to Amir for testing). The SA-XR57 is currently fed from a NAD C658 source. I also have a RME ADI-2 DAC (primarily used for headphone listening at my computer) which I could lug over for another data point.

 

[wynpalmer]

Last week we listened to a meticulously restored Otari at 15ips and universally preferred simple transfers to tape of SACD downloads to the originals. The system was almost totally bespoke valve based amplification/speakers. The general opinion (this was not blind) was that the low frequency HD issues with tape played a role.

This MX50 has the original electronics, but with the opamps swapped out and the appropriate caps replaced with "audiophile" electrolytics and polyprops. I've also built up extensive sections of the schematics in LTspice and performed simulations. At one point I also replaced the entire record/replay chain with tube circuitry (not my own design), but that was abandoned.
The mechanics are pristine, with a new idler wheel etc. and proper lubrication. The W&F has been measured, and is well within spec at (although not as good as my friend's Studer A810, but the difference is inaudible). The record/read back paths have been properly calibrated- I have the appropriate MRL tapes- and the response measured, so that it too is within spec. The head "bump" at 15IPS is less than 1dB as I tweaked the 100Hz setting to trade off 100Hz flatness versus overall LF error.
I can play back tapes- I have a number of 15IPS NAB safety masters taken from a CBC radio station, plus other more recent releases- digitize them, and play back that output versus the tape in a blind AB mode, and as yet no-one has been able to tell the difference- for whatever that's worth.
Playing back the recordings of hires digital versus the digital version in a blind AB test with carefully adjusted volume matching, does indeed seem to sound "better", and the speculation is that the head bump contributes, but that also the increased benign harmonic distortion and the soft limiting of the tape medium may be part of the process.

 

[scott wurcer]

Playing back the recordings of hires digital versus the digital version in a blind AB test with carefully adjusted volume matching, does indeed seem to sound "better", and the speculation is that the head bump contributes, but that also the increased benign harmonic distortion and the soft limiting of the tape medium may be part of the process.

Sums up what our short session found. Personally I don't have any interest in R to R, the time and energy Kevin put into this was considerable. The tube electronics were everything outside of the deck, its internals were reworked the same way.

 

[wynpalmer]

Sums up what our short session found. Personally I don't have any interest in R to R, the time and energy Kevin put into this was considerable. The tube electronics were everything outside of the deck, its internals were reworked the same way.

I don't disagree. I had a bunch of tapes from my time in Canada and a friend that bought an A810 and was raving about it ( he still does).
The fully functional deck was only c. $600 so it was well worth it, if nothing else as a conversation piece, and it's added some entertainment during retirement, which is always welcome. The renovation was much more than the initial price, but straightforward to do.
We did an AB test between the decks, and surprisingly preferred the Otari over the Studer.
I rarely use it. I've digitized the tapes and I listen to those. It's so much more convenient.
My friend continues to proselytize unreservedly.

 

[RayDunzl]

This may be old news, but I just noticed it:

https://benchmarkmedia.com/blogs/reviews/ahb2-lab-report-amir-majidimehr-audiosciencereview-com

@amirm

 

[avm]

Really impressive performance but for the price it is exactly what one would expect I guess. Suppose I would like to pay one tenth for an also very capable amp, then the first thing I would think of is the Akitika power amp. Then I would immediately think about how these two compete with each other.

 

[JohnYang1997]

Really impressive performance but for the price it is exactly what one would expect I guess. Suppose I would like to pay one tenth for an also very capable amp, then the first thing I would think of is the Akitika power amp. Then I would immediately think about how these two compete with each other.

Ahb2 has twice the power and 1/10th of distortion measured. But like you said, for the price it's expected. Neurochome has some kits that are very competitive.

 

[Sal1950]

This may be old news, but I just noticed it:

https://benchmarkmedia.com/blogs/reviews/ahb2-lab-report-amir-majidimehr-audiosciencereview-com

@amirm

Amir is famous now, reviews being quoted by a manufacturer.

Ahb2 has twice the power and 1/10th of distortion measured. But like you said, for the price it's expected. Neurochome has some kits that are very competitive.

I'm not active in the DIY crowd and had not heard of Neurochome. Some very interesting stuff over there!
https://neurochrome.com/products/modulus-686

 

[Kal Rubinson]

I'm not active in the DIY crowd and had not heard of Neurochome. Some very interesting stuff over there! https://neurochrome.com/products/modulus-686

Yes. His Universal Buffer looks attractive for assembling into a multichannel monitor control.

 

[JohnBooty]

Large woofers reproduce percussion instruments in a convincing way that smaller drivers never do (unless you have a big array of them.) Power compression is real. Modern midwoofers can sound pretty amazing but they will never give you what a big cone can.

[...]

The tactility of bass in large drivers is one of those things which conventional measurements don't do a great job of representing; it's not a FR issue or a directivity issue but it's very real. Low distortion in the 30-120hz area is a good place to start but I think it's more than that.

Subjectively, this is my experience too. I hate to mention such a subjective belief/theory on ASR, but I am a believer in this.

 

[DonH56]

Perhaps the speaker distortion would be better served split into its own thread? @Thomas savage ?

 

[Thomas savage]

Perhaps the speaker distortion would be better served split into its own thread? @Thomas savage ?

Done , if I missed a post let me know the number .

Back to the benchmark amp...

 

[rbradshaw]

So, ever since I first read this review, I've been eager to get my hands on one but I was a bit hesitant because of the cost.

Then I realized they're only 10 miles away from me!

How can I not have this amplifier powering my system when it's made in my hometown? #buylocal!

 

[NTomokawa]

Perhaps unsurprisingly, Benchmark has, again, set the benchmark.

Nice separation between the power and amplifier boards, too.

Take note, Audio-GD/Accuphase/Esoteric/Luxman/whatever "exotic Hi-Fi brand"...