Benchmark AHB2 Review (Updated Measurements)

[Kal Rubinson]

Do you mean that it's performance won't be bettered in your lifetime?

No. It means that I do not expect they will be sufficiently bettered in my lifetime.

 

[Sokel]

Is there any threshold in it's DC offset detector?
How does this work?
It's one of the most important protections and I don't see any mention about it.

We know some other have similar but often fall short like the older hypex in the older thread who has an In protection but allows up to 12V (!) before it kicks in.
(don't know about the new NCxxxx though)

 

[wilbur1]

I bought one of these a year or so ago, thinking - rather, hoping - it might be an upgrade on my ancient (but beloved) Nelson Pass-designed Forte 4 (just 50 wpc pure class A, but able to carry an enormous amount of current when needed). The Benchmark sounded good, but it was ultimately not in the same cosmos as the Forte in all sorts of ways. Now I have very efficient speakers, and the Forte can drive these easily, and it might struggle with more difficult loads, but the Benchmark could not go as loud as the Forte, nor were instrumental timbres as accurate. I listen to almost exclusively Classical at high-res, mostly via multichannel SACD/Blu-ray audio, so instrumental and vocal timbres are my main focus. The Benchmark was quieter when no music was playing, but I really don't think too many people drop $3,500 on an amp to listen to silence when it is not playing anything, so that is a dumb reason to get it. I am sure this is a fine amp, but, as I said, it was not even close to a design that is getting on for a half-century old now, so maybe there is more to learn still! I have appreciated the Forte even more since trying the Benchmark, however, and they were as good as their word when I returned it for a full refund after a few weeks. No complaints, but for super-discerning listeners this may still not be the answer. I had hoped it would be, but no matter how well it measures, it is the sound in the end that is everything, and this wasn't as good as my (still beloved) Forte. Everyone else who heard it in comparison agreed.

 

[Sokel]

Well I believe there’s been a couple of reviews of NCx500 based amps that prove they’re objectively superior. Then they also have 4x the power output. They also have far fewer parts in the BOM. Less parts mean less parts to fail. And even if they do it’s all module based and easy for anyone to repair in the field with minimal skills.

Let’s have a look at the 2 main PCB’s in the AHB2:

View attachment 338352View attachment 338353

Now let’s have a look at an NCx500 example:
View attachment 338354

Far less parts and simple module based. The SMPS1200 power supply has been in production for over 15 years. And has undergone like 7 revisions. So it’s well known for its rock solid reliability. Hypex amp module reliability history has been rock solid since I built my first UCD amp in 2007.

4 times the power yes,but what I can't see in NCx's pic is 4 times the thermals (unless there is active which I can't see)
I wouldn't go near if I wanted to use it in some demanding application (or I would put it in a case properly calculated for worst case scenarios) .

 

[USER]

Years ago I had a Forte Model 4A (50W) that I was selling as I was upgrading to a higher-wattage amplifier. My secondary system was then run through a cheap NAD 320BEE (50W) that I bought during my college years. Before I packed it up I decided to directly compare the two and realized that everything I thought was great about the Forte was all in my head. It was indistinguishable from the NAD. Whatever audiophile imagination I had remaining left me that day. Years later I was pleasantly surprised by Amir's review of the NAD and its terrific performance. The facts simply make sense.

Today I am happy with my Benchmark (I too have pops for the record) and several Hypex NC252MP-based amplifiers. But I know I would be just as happy with my old NAD if the 50W was enough. I regret selling it.

That's the thing about anecdotes. There's always another one that can muddy it up and really leave you no where. Measurements can be confirmed and backed up.

 

[fpitas]

That's the thing about anecdotes. There's always another one that can muddy it up and really leave you no where.

But this one time at band camp...

 

[daniboun]

I bought one of these a year or so ago, thinking - rather, hoping - it might be an upgrade on my ancient (but beloved) Nelson Pass-designed Forte 4 (just 50 wpc pure class A, but able to carry an enormous amount of current when needed). The Benchmark sounded good, but it was ultimately not in the same cosmos as the Forte in all sorts of ways. Now I have very efficient speakers, and the Forte can drive these easily, and it might struggle with more difficult loads, but the Benchmark could not go as loud as the Forte, nor were instrumental timbres as accurate. I listen to almost exclusively Classical at high-res, mostly via multichannel SACD/Blu-ray audio, so instrumental and vocal timbres are my main focus. The Benchmark was quieter when no music was playing, but I really don't think too many people drop $3,500 on an amp to listen to silence when it is not playing anything, so that is a dumb reason to get it. I am sure this is a fine amp, but, as I said, it was not even close to a design that is getting on for a half-century old now, so maybe there is more to learn still! I have appreciated the Forte even more since trying the Benchmark, however, and they were as good as their word when I returned it for a full refund after a few weeks. No complaints, but for super-discerning listeners this may still not be the answer. I had hoped it would be, but no matter how well it measures, it is the sound in the end that is everything, and this wasn't as good as my (still beloved) Forte. Everyone else who heard it in comparison agreed.

Any measurements for the Nelson Pass model 4 ? from experience our ears often lie to us....

 

[amirm]

@amirm how old was the unit from this 2nd review? Was it new or had it been in use for period of time?

Brand new, drop shipped to me.

 

[sq225917]

I'd warrant the ahb2 is a good dB better in noise and distortion than Nelsons offering. You might prefer the sound, but by any measure his amps aren't as good. And that's the crux, do we buy what we like or what measures best.

 

[amirm]

The people who have told me they have gone to Benchmark AHB2 have said the analysis paralysis was killing them so they bought that. I congratulate them on that and we go about our ways. It is an incredibly safe decision to buy this amplifier. There is only one model. It has superb performance. And even in absence of hard data, we know there are no riots around it breaking.

My only caution to people is that it may not have enough power. They don't for me in stereo. But if they don't need the power, that is that.

 

[USER]

Any measurements for the Nelson Pass model 4 ? from experience our ears often lie to us....

The Model 4 is a Michael Bladelius (and not Nelson Pass) design. It's an interesting amplifier in that utilizes IGBTs and is based on an approach that is the complete opposite of Benchmark in that the aim is to make it feedback-free. (See the attachment for a very broad overview and the usual marketing mumbo jumbo.) I searched long and hard but found no real measurement-based information about it. Simply "0.1%" THD at what I presume to be 50W at 8ohms at 1kHz, which should mean that it will do the job. The manual of the matching F44 preamp has a little more information, though nothing that would satisfy anyone here. To these ears it sounded as clean as the NAD 320BEE, which is a compliment, lol! (Though that 90 dB SINAD is no joke.)

The only audibly bad sounding piece of equipment (non-speaker) I ever owned was a Conrad Johnson Motif MC-8 preamp. The mental gymnastics I must have done to tell myself that it was good... "Sweet." "Syrupy." Ugh, what a fool I was.

Edited to add a little more info.

 

[Whoareyou]

The people who have told me they have gone to Benchmark AHB2 have said the analysis paralysis was killing them so they bought that. I congratulate them on that and we go about our ways. It is an incredibly safe decision to buy this amplifier. There is only one model. It has superb performance. And even in absence of hard data, we know there are no riots around it breaking.

My only caution to people is that it may not have enough power. They don't for me in stereo. But if they don't need the power, that is that.

In your case, is comment specific to Salon 2's or you want more power in general?

 

[amirm]

In your case, is comment specific to Salon 2's or you want more power in general?

It is general advice I give to people (get more power than you think you need) but in my situation, it definitely applies with Salon 2 in very large space.

 

[Mike-48]

I hope this will not get used as evidence for expensive audiophile connectors.

Are you kidding? SpeakON connectors are dirt cheap . . . like $3 apiece, last time I looked.

 

[Mike-48]

When I see a long term reliable one, I’ll buy one, I have a few friends that bought them with in the last 2 yrs. One bought one, raved about it, the other rushed to buy them. All of them have failed, none made it a year of normal use. One had smoke pouring out the case vents, one made a huge popping sound and then dead silence, the others failed to power up the next time. Before I bought my AHB2s, I looked at a NAD, Bel Canto and an Elac (all class Ds). I liked the fact the Benchmarks are built about 10-12 miles from my house, did not hurt, I know a couple of the people who work there, if I have an issue, they are local. The concept looks great, but before I buy one, I want to see some long term reliability

I respect your desire for reliability, and I, too, would prefer to buy from a manufacturer close to me, in case of any issues. I like to buy things I can keep for a long time, and I usually do keep good things for a long time.

That said, your friends seem have have had very bad luck. I've also several friends with various Class D configurations made by Buckeye, VTV, and others, and none has reported a failure yet. My pair of Apollon amps (PuriFi 1ET400A-based) have been in service for 3 years now with no issues. That's not really long term by my perspective, but I've not seen the junkyard fire your friends have reported.

My own calculus was that lower savings and higher power made the Apollon amps the better buy. Since then, I've heard the AHB2 in my system and observed that a single one could drive my speakers fine -- with no clipping. So despite my enthusiasm for power (audio power, that is) either path would have worked for me.

 

[ahofer]

I've also several friends with various Class D configurations made by Buckeye, VTV, and others, and none has reported a failure yet.

March Audio p252 now 4+ yrs with no issues, NAD c298 bought used a year ago, also going strong.

 

[AdamG]

While we understand that some amount of comparison conversions are going to be relevant. After all this product name “Benchmark” is an invitation for comparison with other Amps. So try to keep it relevant to the Product Revied and let’s try to maintain a conversation that is about this Amp and the test bench results.

Thank you for your support and understanding. We like to keep review threads mostly on topic for the first 20 pages.

 

[lordhumungous]

I had this amp and it’s a great amp . Stellar . I give it a 9.8 out of 10.0 rating. It just doesn’t have enough power for me in a large room . That’s a subjective impression but also one that Amir cautions about .

 

[Titmouse]

What would be some rules to help determine in advance if this amp has enough power for the purchaser?

 

[AdamG]

What would be some rules to help determine in advance if this amp has enough power for the purchaser?

Here is a good link. There are many available just do a search for how much amp do I need.

Crown Audio - Professional Power Amplifiers | English (US)

www.crownaudio.com

Here is an existing ASR Thread about this topic: Happy reading

Amplifier : how much power do you need

For those who are interested, here's a quick way to estimate your amplifier's power needs, based on your average SPL listening level : 1- You need the crest factor of your music track, usually between 10-20db : http://www.richardbrice.net/leq.htm#:~:text=Symphonic, orchestral music can...

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