Review and Measurements of Benchmark AHB2 Amp

[rdenney]

I disagree that this is a reasonably priced power amp. On top of that they sell direct so their profit margin must be huge. Also they are using technology very similar to Carver SS amps of the 80"s and 90's that you can buy for 400 dollars that have twice the power.

I'm not sure I'd want to put that Carver amp in a commercial setting. And I say that as the owner and user of a commercial Carver PM-300. Also, I suspect the distortion of that Carver is probably 25-30 dB higher than the Benchmark, which may not be important in any given case, but which is there all the same. One could certainly pay a LOT more and get a LOT less.

What was the price of that Carver amp back in the day? I've had mine for probably 30 years and don't recall. But you can't compare the primary and secondary market for anything.

Finally, price is not the same thing as cost.

Rick "a fan of Carver products but this is apples and oranges" Denney

 

[Bridges]

I'm not sure I'd want to put that Carver amp in a commercial setting. And I say that as the owner and user of a commercial Carver PM-300. Also, I suspect the distortion of that Carver is probably 25-30 dB higher than the Benchmark, which may not be important in any given case, but which is there all the same. One could certainly pay a LOT more and get a LOT less.

What was the price of that Carver amp back in the day? I've had mine for probably 30 years and don't recall. But you can't compare the primary and secondary market for anything.

Finally, price is not the same thing as cost.

Rick "a fan of Carver products but this is apples and oranges

 

[Bridges]

I believe Amir's opinions and measurements, this is must be a very good power amp, but 3000 bucks is neither apples nor oranges.

 

[MaxBuck]

I believe Amir's opinions and measurements, this is must be a very good power amp, but 3000 bucks is neither apples nor oranges.

$3,000 is actually both apples and oranges. Different quantities of each to get there, though.

 

[Chester]

To all those F208 owners who were saying they really need a pair of AHB2’s as monos…..how loud do you listen?! I recently acquired a pair and running my F208’s on just one, I get scared way before the AHB2 does

I write this for any future owners who may assume the same as I did. Try one first before shelling out for a pair.

Don’t worry though, the other one is working out nicely in a second system.

 

[radix]

To all those F208 owners who were saying they really need a pair of AHB2’s as monos…..how loud do you listen?! I recently acquired a pair and running my F208’s on just one, I get scared way before the AHB2 does

I write this for any future owners who may assume the same as I did. Try one first before shelling out for a pair.

Don’t worry though, the other one is working out nicely in a second system.

I have the F228be (90 dB sensitivity vs 88.5 for the F208), but I listen about 3m away in a room with open archways to other parts of the house. I want to get up to about 95+ dB SPL for a party (with 6-9 dB headroom). That's about 220W, which is more than the stereo output, but quite a bit less than the mono output. Normally I'm listening at much much lower volume.

It's also important that the input sensitivity be set right for your preamp. Some people might have it on low, which will really under power the amp if not using the Benchmark preamps (or another really hot preamp).

 

[12Many]

To all those F208 owners who were saying they really need a pair of AHB2’s as monos…..how loud do you listen?! I recently acquired a pair and running my F208’s on just one, I get scared way before the AHB2 does

I write this for any future owners who may assume the same as I did. Try one first before shelling out for a pair.

Don’t worry though, the other one is working out nicely in a second system.

Did you notice a benefit in the quality of the sound (not the volume) when you ran two AHB2 amps?

 

[Chester]

No, nothing between them for me.

 

[GXAlan]

The Anthem STR preamp was measured on Audioholics.@ 106 dB SNR analog (1V in, 2V out) and 110 dB SNR digital (0dBFS in, 2V out).

Just to point out that the Audioholics measurement of SNR is not the same as SINAD. The SINAD graph we can see here:

0.0006% at 1 kHz = 104.4 dB.

I’ve never seen a full-featured preamp with better than 105 dB SINAD. The best traditional analogue preamps are in the 90’s.

Kenwood L-08C Pre-amplifier Review (Vintage Audio, QuirkAudio restored)

Kenwood L-08C Pre-Amplifier Measurements (Vintage Audio) Part 1: Kenwood L-08M Monoblock Amplifier Review https://www.audiosciencereview.com/forum/index.php?threads/kenwood-l-08m-monoblock-amplifier-vintage-review.37756/#post-1327414 If you haven't read Part 1, please give that a read...

www.audiosciencereview.com

I got to 105.7 dB using a 108 dB signal generator . That’s from the 80’s not the 90’s though.

 

[denydog]

I can confirm Chester's advice regarding F208s and the Benchmark amp. I've never seen a clipping light. But I usually use both of mine like radix does. Two of them just seem to fill up the rack nicely.

The recent purchase of the AHB2s was to complete the dream system I've always wanted, I got the pair so I wouldn't have to think about amplification again.

I'm using the Topping Pre90 with the amps in low gain. Next move is to get longer interconnects and shorter speaker cables, moving the amps next to each speaker. Can't do that with one amp. Cheers

 

[Titmouse]

Subjective review below...

Went from a Parasound a23+ to the AHB2 after viewing this thread. Using a media PC to Topping e70 DAC directly into amp (balanced) powering Kef R5 speakers

Woofers: This is the first time I've noticed my speaker woofers utilizing their capability, even though there are less advertised watts of power in the AHB2. It's not like adding two huge subwoofers to the room, but the R5 woofers are now present and useful

Imaging: a23+ has three rather distinct locations for sound to sit when playing tracks that utilized stereo channel separation. Left / center / right. Not much in between. AHB2 does not present like that, I now perceive audio in more locations between the speakers. And when something is far left / right it doesn't seem like there is a hard edge of where it stops, more of a general area on left / right. This is a weird one to me, not sure what would cause this from a technical standpoint, speakers haven't moved. Interested to know, if its placebo I'm fine with that too

"Flatness": As some reviews stated, I also had the impression that the sound was somewhat "flat" when compared to my a23+. After listening for a few hours I plugged the a23+ back up, immediately felt a23+ was thin. I think I confused presence of bass from AHB2 as being flat, wasn't used to hearing fuller range of sound. Removing a23+ and switching back to AHB2 the sound felt correct, like I disabled a high pass filter

Enough Power: I sit about 9 feet away, have not gotten the amp to clip with my speakers. Volume reached my pain threshold so I stopped, no lights came on

Sound "Depth": a23+ did have one aspect I liked, most audio tracks felt like they were not playing right in my face. Adding a subtle VST reverb filters helps me perceive more depth when desired

Neutrality: The output is what I perceive to be more neutral in my current room setup. Looking forward to customizing the sound using filters. Couldn't do much with the a23+ as all my filter attempts made things sound uncomfortable or funky. Was locked into the base flavor

Smooth Loudness: I believe it's subtly smoother sounding compared to a23+ when playing louder volumes

Visual Appeal: I like the way it looks in black, smaller proportions work well with topping sized DACs / Preamp boxes

Power LED: AHB2 has no way of dimming "power on" LED that I can find when searching the manual online, it's brighter than I like. Is this adjustable?

Price for Value: About double the price of an a23+. I am willing to pay that extra for what it offers after demoing in my room. But this wasn't a life changing experience. More of "Oh, this is very nice, I can keeping listening to this". Gut response I would pin the value at $2,700 or less. I wasn't confident enough to buy used so I paid $3,500 directly

Thanks ASR for helping me part with my money faster than before. I've got two E15HP2 subs on the way...(they were out of stock of F12's in white)

 

[kadajawi]

The AHB2 has about the same noise performance in all settings. However, you will be hard pressed to find 4 Vrms or 2 Vrms outputs that can deliver a 132 to 135 dB SNR to match that of the AHB2.

Not quite there, but some MiniDSPs should get close, right?

 

[amirm]

An updated set of measurements just posted: https://www.audiosciencereview.com/...hmark-ahb2-review-updated-measurements.50844/

 

[sandeep_s300]

I bought today a pair of the BHK AHB2 . It is intended to power the Revel F228BE fronts in mono mode. Currently, I have Apollon Hypex NCX500 stereo amp that is powering the Revels and on its way, a 3 channel hypex ncx500 amp being built by Buckeye. It was a low risk purchase as I have purchased them used.

Idea is to test side by side how I perceive the sound coming out of AHB2 vs Hypex NCX500. Will also check AHB2 in stereo vs mono . With Mono, the power at 8ohms will be similar to the Hypex ncx500.

If I cannot find any audible difference - AHB2 will be back in the market , otherwise, the Apollon. Likewise, if stereo vs mono don't make any audible difference in my room (treated but small size) , then will use one AHB2 as stereo for the f228be fronts and another ahb2 as mono (just because there is nothing else to connect on the other output) with revel c426BE center speaker (Amp matched for LCR for HT setup) . The 3 channel buckeye will use for surround speakers.

The previous owner also have benchmark XLRs and SpeakOn speaker cable . I think this is where I am more nervous about. The speaker cables have earned some good user feedbacks. I have a tellurium black diamond speaker cable coming from UK which is to match the black diamond XLRs connected to Eversolo A8. The subjective test will be benchmark speaker cables vs tellurium . Tellurium Q cables using the ahb2 as stereo vs mono (banana plugs).

Does anyone tried the benchmark speaker cables (speakon) ? Just want to know your findings about them.

 

[radix]

I bought today a pair of the BHK AHB2 . It is intended to power the Revel F228BE fronts in mono mode. Currently, I have Apollon Hypex NCX500 stereo amp that is powering the Revels and on its way, a 3 channel hypex ncx500 amp being built by Buckeye. It was a low risk purchase as I have purchased them used.

Idea is to test side by side how I perceive the sound coming out of AHB2 vs Hypex NCX500. Will also check AHB2 in stereo vs mono . With Mono, the power at 8ohms will be similar to the Hypex ncx500.

If I cannot find any audible difference - AHB2 will be back in the market , otherwise, the Apollon. Likewise, if stereo vs mono don't make any audible difference in my room (treated but small size) , then will use one AHB2 as stereo for the f228be fronts and another ahb2 as mono (just because there is nothing else to connect on the other output) with revel c426BE center speaker (Amp matched for LCR for HT setup) . The 3 channel buckeye will use for surround speakers.

The previous owner also have benchmark XLRs and SpeakOn speaker cable . I think this is where I am more nervous about. The speaker cables have earned some good user feedbacks. I have a tellurium black diamond speaker cable coming from UK which is to match the black diamond XLRs connected to Eversolo A8. The subjective test will be benchmark speaker cables vs tellurium . Tellurium Q cables using the ahb2 as stereo vs mono (banana plugs).

Does anyone tried the benchmark speaker cables (speakon) ? Just want to know your findings about them.

You should lookup other threads about doing side-by-side amp comparisons. You want to get them level matched and have an easy speaker switch so you can go between the two amps easily and quickly, as people generally don't have great sound memory. you will also want to properly match the AHB's sensitivity with your preamp's output.

You might be able to play the A8 in mono and use the internal balance to level match the two amps, so the L is, say, the AHB and the R is the Hypex and then use a speaker switch between them. I'm sure someone has posted how to do level matched amp comparisons with a single preamp.

My hypothesis is that you'll only notice a difference when you get to high volumes and the difference between a class D and a class ABH headroom come in to play.

 

[sandeep_s300]

You should lookup other threads about doing side-by-side amp comparisons. You want to get them level matched and have an easy speaker switch so you can go between the two amps easily and quickly, as people generally don't have great sound memory. you will also want to properly match the AHB's sensitivity with your preamp's output.

You might be able to play the A8 in mono and use the internal balance to level match the two amps, so the L is, say, the AHB and the R is the Hypex and then use a speaker switch between them. I'm sure someone has posted how to do level matched amp comparisons with a single preamp.

My hypothesis is that you'll only notice a difference when you get to high volumes and the difference between a class D and a class ABH headroom come in to play.

I will try to do quick switch setup. But usually I don’t analysis seriously that time as brain and emotions play out . I record the sounds coming out form each and then next day a few of us get them - whereby we put our headphone and listen to the tracks and take notes . The other people don’t know which is what until they finish listening and providing feedback.

 

[Doodski]

I will try to do quick switch setup. But usually I don’t analysis seriously that time as brain and emotions play out . I record the sounds coming out form each and then next day a few of us get them - whereby we put our headphone and listen to the tracks and take notes . The other people don’t know which is what until they finish listening and providing feedback.

Wowzer... When recording the audio from a transducer (Microphone.) and then playback through a second transducer (Headphone or speaker.) the audio is changed.

 

[dlaloum]

You should lookup other threads about doing side-by-side amp comparisons. You want to get them level matched and have an easy speaker switch so you can go between the two amps easily and quickly, as people generally don't have great sound memory. you will also want to properly match the AHB's sensitivity with your preamp's output.

You might be able to play the A8 in mono and use the internal balance to level match the two amps, so the L is, say, the AHB and the R is the Hypex and then use a speaker switch between them. I'm sure someone has posted how to do level matched amp comparisons with a single preamp.

My hypothesis is that you'll only notice a difference when you get to high volumes and the difference between a class D and a class ABH headroom come in to play.

Another observation, looking at most (not all) Class AB vs Class D....

Usually a class D amps rated output is its max (or close to it) - it usually has very little additional "Headroom"

Typical Class AB amps on the other hand, often have substantial additional "Headroom" for short term peaks.

This I believe mostly relates to differences in the typical power supplies used...

The gotcha to watch for of course, is that the comparison's especially when headroom considerations are part of it, is that a 150W Class D, might be a match for a 100W AB.... whereas 100W vs 100W, would frequently give the AB a substantial edge...

Many would point to the typically better W@8ohm rating of a class D vs class AB at any given price point.... however once the headroom is taken into consideration that separation/advantage, shrinks substantially!

 

[yanm]

I will try to do quick switch setup. But usually I don’t analysis seriously that time as brain and emotions play out . I record the sounds coming out form each and then next day a few of us get them - whereby we put our headphone and listen to the tracks and take notes . The other people don’t know which is what until they finish listening and providing feedback.

It seems like a good approach: you can level match very precisely after the fact and use an automated ABX software to avoid any sighted bias. Be sure to always use the same playback conditions (same sound level, same speaker, same mic position and settings, etc.) not to introduce any other variables.

I am however wondering how good the recording side (mic, ADC, etc.) has to be in order to capture the very small differences that the two amplifiers may introduce?

I guess that apart of corner cases (e.g., close to saturation) there should be no to very little audible differences. I fear that the latter will be difficult to capture.

[edited typos]

 

[JSmith]

class ABH

Review and Measurements of Benchmark AHB2 Amp

The AHB2 has now been tested in the German trade magazine STEREO 8/2022 and has scored quite well. However, the performance data in bridge mode could not be reproduced. Unfortunately, there are no further details on this. Here is the measured DF at 4ohms (not bridged), which I have not seen...

audiosciencereview.com

The AHB2 has a class-A/B output section with dual bipolar output rails (class-G). A class-A correction amplifier provides feed-forward correction. The main amplifier and correction amplifier are passively summed at the output.

JSmith