Review and Measurements of Benchmark AHB2 Amp

[misterdog]

I don’t know what I don’t know

Neither do most audiophiles, welcome aboard.

You will get people agreeing and disagreeing in equal measure.

I have one and I like it.

 

[misterdog]

I was quoted $300+ for the swap, so not really worth it for me. I'll just have to deal with the bright/harsh sound of the silver AHB2 over the dark/warm sound and black background of the black AHB2. /s

£ 324 here in the UK, though we have a local anodizer and removing it can't be that complicated.

 

[ChMaKi]

Is more power good for something other than playing louder? I hear people say the Salon2s need power, but why? Is it just because the speaker’s sensitivity is lower compared to others or is there some other reason? @amirm (can you tag people here) Inoticed that you have Mark Levinson amps for your Salon2s. Is there a reason for that or did you buy them before you started doing the measurements? I realize that may sound like a cheeky question but it isn’t meant to be, I promise. Would you buy the Levinson amps all over again if you were in the market today and, if so, why? If you’ve already answered this somewhere else I apologize, just point me to the right thread if you please.

 

[josh358]

Hello all, I am new to the forum and a newbie/wanna be audiophile. I would very much like to be in the camp that measurements matter most and that anything that measures well will sound great. However, I don’t know what I don’t know. Do I just buy a Benchmark amp and call it a day or is there something else that would sound better to my ears. I see people selling used benchmarks occasionally and that makes me wonder why? Are they the type of people that are never satisfied or did they find something better. If so, what is it and what makes it better? Any thoughts are appreciated.

I've rarely seen used Benchmarks for sale, and the asking price is very high given the original price of the item. People seem to be keeping them, and those who sell may have other reasons, e.g., they need more power than the Benchmark can provide.

Measurements? Well, yeah, if you can interpret them. It isn't always easy and the measurements aren't always appropriate or complete. Much of what can be measured can't be heard at all, because the ear is less sensitive than the measurement equipment. In other cases, the measurements apply to only a subset of use cases or scenarios. Sometimes, it's hard to know whether something is audible because of inadequate psychoacoustic data. I concur, though, with whoever warned you against going down the audiophile rabbit hole, since in uncontrolled listening you will end up hearing differences that don't exist. At the same time, some people like to think that whatever measurement suite they're looking at says everything about the sound of a piece of gear. Typically, it doesn't.

That said, I think you'll find that once you buy a good amp, any differences you hear between them will be subtle at best, providing you use them in their linear region. There are differences -- I did a blind level-matched listening test with the Benchmark, a Parasound A21, and some other amps -- but being able to hear a difference doesn't mean that the difference is significant.

If I were to summarize the results of my comparison, the Benchmark was cleaner, while the A21 was better on piano transients. (I say "better" because it sounded more to me like a real piano -- but that's obviously a subjective conclusion on my part).

But again, these differences are subtle. The only reason I can think of not to go with the Benchmark is that it doesn't fit your needs -- not enough power, too expensive, too small to impress your girlfriend, what have you. And you could save money with a larger, heavier, and less expensive amp. Conversely, you might consider something like the Purifi -- I'd like to try that one myself.

All of this is perhaps too complicated. I have a Benchmark. I like my Benchmark. If it fits your needs (power, mostly) and you buy it, I doubt that you will ever want to replace it with another amp -- it's SQ/BP (sound quality to back pain ratio) is insanely good.

 

[josh358]

Is more power good for something other than playing louder? I hear people say the Salon2s need power, but why? Is it just because the speaker’s sensitivity is lower compared to others or is there some other reason? @amirm (can you tag people here) Inoticed that you have Mark Levinson amps for your Salon2s. Is there a reason for that or did you buy them before you started doing the measurements? I realize that may sound like a cheeky question but it isn’t meant to be, I promise. Would you buy the Levinson amps all over again if you were in the market today and, if so, why? If you’ve already answered this somewhere else I apologize, just point me to the right thread if you please.

Yes, power is for playing louder. And as you say, that depends on the sensitivity of your speakers as well as your room, the kind of music you listen to, and your preferred listening levels. For some reason, people don't take a scientific approach to this. Get an inexpensive SPL meter, set it to fast, and listen to the loudest track you ever listen to. Then add 10 dB to the figure, because despite what people think, the fast setting on an SPL meter is not a peak reading. Once you've done that, there are some online calculators that will let you calculate amplifier power at your listening distance.

What happens if the amplifier is too small? Well, you get clipping -- the top of the waveform gets lopped off. Depending on the instrument, that can be audible anywhere from 1 to 10 dB. In this day and age, with good, economical high power amplifiers, I don't think there's any need to tolerate clipping.

 

[RobS]

Curious, does anyone use the AHB2 as a headphone amplifier? What has been your experience with them? How do they do with high impedance cans like the Sennheisers?

 

[RobS]

Yes, power is for playing louder. And as you say, that depends on the sensitivity of your speakers as well as your room, the kind of music you listen to, and your preferred listening levels. For some reason, people don't take a scientific approach to this. Get an inexpensive SPL meter, set it to fast, and listen to the loudest track you ever listen to. Then add 10 dB to the figure, because despite what people think, the fast setting on an SPL meter is not a peak reading. Once you've done that, there are some online calculators that will let you calculate amplifier power at your listening distance.

What happens if the amplifier is too small? Well, you get clipping -- the top of the waveform gets lopped off. Depending on the instrument, that can be audible anywhere from 1 to 10 dB. In this day and age, with good, economical high power amplifiers, I don't think there's any need to tolerate clipping.

Good post, well said.

The crest factor of music has played a large role in how much power I've needed from an amplifier. I have a few albums that have excellent dynamic range and very limited compression that made a few amplifiers I owned run out of gas at my desired dbSPL level.

 

[misterdog]

it's SQ/BP (sound quality to back pain ratio) is insanely good.

That requires a separate like..

 

[josh358]

That requires a separate like..

 

[Kal Rubinson]

That said, I think you'll find that once you buy a good amp, any differences you hear between them will be subtle at best, providing you use them in their linear region. There are differences -- I did a blind level-matched listening test with the Benchmark, a Parasound A21, and some other amps -- but being able to hear a difference doesn't mean that the difference is significant.

Agreed.

If I were to summarize the results of my comparison, the Benchmark was cleaner, while the A21 was better on piano transients. (I say "better" because it sounded more to me like a real piano -- but that's obviously a subjective conclusion on my part).

And, significantly, based on the particular piano recordings you chose. I'd speculate that there might be other piano recordings where your subjective preference would be otherwise.

 

[Dacapalooza]

...That said, I think you'll find that once you buy a good amp, any differences you hear between them will be subtle at best, providing you use them in their linear region. There are differences -- I did a blind level-matched listening test with the Benchmark, a Parasound A21, and some other amps -- but being able to hear a difference doesn't mean that the difference is significant.

Systemwide thing.
Not as simple as merely comparing an amp in some cases.

If you do not have a decent DAC than it is that much harder to tell the diff maybe. Or unpredictably.

Also, you can have "bottlenecks."
A linear PSU reclocker in your path. A failed capacitor that you do not even know about. Etc.
Placing a very good amp vs an OK vs bad might not be so 100% detectable with bottlenecks. Not to mention bad speakers/room.

Ideally one would have a lab like environment. Like Revel has for their listening room. And one used an ASR approved DAC that would be one's best hope to know if one can hear a difference and how much. But then again if your environment can't reproduce the lab environment it might be a waste of time to go that far. Just we will not know how much better a Great amp is vs bad amp and how best to take advantage of it.

I will find out once and for all if system wide if I can hear a difference. If buying hifi/ASR approved components makes sense for my environment, selfishly, internally and with all my soul. This is not cheap stuff.

My bottlenecks are bad room and my current amp that I am replacing with AHB2's that oddly only comes in 2 channel versions. My 9 YO speakers, by an even more odd coincidence, still a current model & ASR approved.

I have an ASR approved DAC that measures better than this amp and a Trinnov 6 channel.

I wonder a Trinnov room vs a good room can I ABX? So maybe my room is mostly taken care of? It sounds great! And I Imagine in mine and most situations, Trinov is the MVP by light years more than any ASR approved component. If I had to buy a PrePro like mere mortals, the ASRness is by far a second consideration after room correction.

I am about to jump the single biggest advancement in my lifetime. From 10 YO non-ASR approved stuff to ASR’s highest of honors system. Can you imagine how bad home theater stuff was 10 years ago when even now it is still not great?

I am about to jump from 12 YO amp. Measures around 70 SINBAD. Not to mention other bad measurements like crosstalk tech from back than.

Now also imagine an ASR approved system with the highest of honors vs ASR approved 10 years from now. Would you be able to ABX that?

I imagine I represent most audio geeks. I have a self-imposed budget. I replace sources every 5 years. Amps/Speakers 10 years. I love that approach because in one swoop you get a big advancement.

 

[Dacapalooza]

My amps came!!! Woohoo! Got 2 serial #'s in a row.
Looks way better in person. Loving the grills. Never had grills.

The first grill matches Oppo's and my OKto dac8. The face plate is way more matte.
It also feels like the Oppo/dac8. It is also way thicker making it look like the actual device case and that the face plate is raised.
The rest of the grills look great but not made of same feel & look as the first.

I can hardly wait to listen. Bought tons of PCM DVD/BD's 24 bits and have been listening for weeks in preparation. I am normally a 100% movie guy, but this forum inspired me to listen to some music.
But first a movie. Got to respect the amps! I'm thinking of LOR 4K as my first movie. Or maybe all of the Avengers movies in 3D.

 

[RobS]

Congrats on receiving the amps! Look forward to reading what you think of your system when you have them slotted in. You gonna try listening to just one in stereo or go straight to mono? Veritcal Bi-amping would be the most ideal IMO.

 

[Dacapalooza]

Congrats on receiving the amps! Look forward to reading what you think of your system when you have them slotted in. You gonna try listening to just one in stereo or go straight to mono? Veritcal Bi-amping would be the most ideal IMO.

Thanks!

I plan to use all 4 channels in my 5.1 system. The fifth I will use my current Krell monobloc temporarily.
Within a few months I plan on getting a Purifi mono solution and match the AHB2's gain by the manufacturer.
I am not getting another AHB2 for just a surround that does not even face me. Rather upgrade all 3 front speakers to the newer Revel Be line next year. Also, I don't want to just waist the extra channel. So I decided to have a mismatched amps in the back for now.

Jury is still out. Might get stereo Purifi for my 2 surrounds and waist the channel. Got time to think about it.

 

[Dacapalooza]

@Dacapalooza do you like The Eagles?

if so, find The Eagles - Farewell 1 Tour - Live From Melbourne BR

Thanks!
I do like the Eagles. I got the Hotel California DVD-Audio. Wow! Sounds amazing even now. Even with Krell mono's.

I hate how live sounds.
I love how Movies/Music with PCM discs that have UPC numbers sound. The recording engineers we use and have used are just amazing.
I imagine that is why I like room correction so much.

Processed sound = Yummy!

 

[josh358]

Systemwide thing.
Not as simple as merely comparing an amp in some cases.

If you do not have a decent DAC than it is that much harder to tell the diff maybe. Or unpredictably.

Also, you can have "bottlenecks."
A linear PSU reclocker in your path. A failed capacitor that you do not even know about. Etc.
Placing a very good amp vs an OK vs bad might not be so 100% detectable with bottlenecks. Not to mention bad speakers/room.

Ideally one would have a lab like environment. Like Revel has for their listening room. And one used an ASR approved DAC that would be one's best hope to know if one can hear a difference and how much. But then again if your environment can't reproduce the lab environment it might be a waste of time to go that far. Just we will not know how much better a Great amp is vs bad amp and how best to take advantage of it.

I will find out once and for all if system wide if I can hear a difference. If buying hifi/ASR approved components makes sense for my environment, selfishly, internally and with all my soul. This is not cheap stuff.

My bottlenecks are bad room and my current amp that I am replacing with AHB2's that oddly only comes in 2 channel versions. My 9 YO speakers, by an even more odd coincidence, still a current model & ASR approved.

I have an ASR approved DAC that measures better than this amp and a Trinnov 6 channel.

I wonder a Trinnov room vs a good room can I ABX? So maybe my room is mostly taken care of? It sounds great! And I Imagine in mine and most situations, Trinov is the MVP by light years more than any ASR approved component. If I had to buy a PrePro like mere mortals, the ASRness is by far a second consideration after room correction.

I am about to jump the single biggest advancement in my lifetime. From 10 YO non-ASR approved stuff to ASR’s highest of honors system. Can you imagine how bad home theater stuff was 10 years ago when even now it is still not great?

I am about to jump from 12 YO amp. Measures around 70 SINBAD. Not to mention other bad measurements like crosstalk tech from back than.

Now also imagine an ASR approved system with the highest of honors vs ASR approved 10 years from now. Would you be able to ABX that?

I imagine I represent most audio geeks. I have a self-imposed budget. I replace sources every 5 years. Amps/Speakers 10 years. I love that approach because in one swoop you get a big advancement.

I think whether you would be able to ABX two things that were made 10 years apart would depend entirely on what they were. Some technologies are pretty mature, others are still changing rapidly. Listen to an amplifier from 1970, and you'll almost certainly be disappointed. Listen to an amplifier from 2010, and you'll be hard pressed to distinguish it from an amplifier made in 2020 -- and even if they do sound different, to know which one (if either) is right.

You're right that it can be hard to evaluate a component in a system with subpar components or a bad room. IMHO, the speakers are usually the bottleneck here. Some have better definition than others. They're both more revealing and less forgiving. But room and setup matter too. Sometimes, the best setup for judging equipment isn't the one you'd want to listen in, or isn't practical in a home setup.

I'm not sure how you'd ABX two rooms. A processor like the Trinov can help tame a bad room, but it can't do everything -- no signal processor can. But whether the Trinov plus a bad room would sound better than a good room without -- who knows? It would depend on the room and on your speakers. You can't EQ out the polar response of a loudspeaker -- if you do that, you'll ruin its on axis response. And you can't EQ out early reflections except for a single location in the room. You also can't fill in major dips in bass response caused by room modes, which aren't minimum phase. I'm also stuck with a bad listening room, and it has taken a lot of work on the acoustics to get it to sound the way it should.

 

[Descartes]

I see they have a few dealers, so they must have room to lower their prices!

 

[Kal Rubinson]

I'm not sure how you'd ABX two rooms.

Just as an experiment, I have done that. Using a Smyth Realiser, I made two independent calibrations, one at the system in my apartment and the other at my system in my house. With these stored in the Realiser memory, I can sit in either location and compare what I hear over the speakers with the Realiser's rendition of it and of the other system. In general, the Realiser sounds identical to the direct sound from the speakers in that room, so I can, in effect, A/B both rooms by switching between them on the Realiser. Quite amazing.

 

[JP]

That was the primary use case for my Realiser - capturing system changes. Always took me a few tries to get a good measurement, and the illusion doesn’t hold up for me without head tracking.

 

[Eurasian]

Just as an experiment, I have done that. Using a Smyth Realiser, I made two independent calibrations, one at the system in my apartment and the other at my system in my house. With these stored in the Realiser memory, I can sit in either location and compare what I hear over the speakers with the Realiser's rendition of it and of the other system. In general, the Realiser sounds identical to the direct sound from the speakers in that room, so I can, in effect, A/B both rooms by switching between them on the Realiser. Quite amazing.

Hi Kal,

Which Smyth system do you use? I'm thinking about picking up a used A8 -- any advice?

Thanks!