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Review and Measurements of Benchmark AHB2 Amp

Eurasian

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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!
 

Kal Rubinson

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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.
Of course!
 

RobS

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I've read reports elsewhere that folks who have used star-quad XLR cables can hear high frequency roll-off, less resolution and overall dullness to the sound. Looking at the cables Benchmark sells for analog connections (Canare L-4E6S), I don't see any roll off until after 20K per Canare's measurements. The star-quad is what Benchmark recommends for both speaker and analog connections.

Are there any measurements that show these characteristics in star-quad cables vs. low capacitance XLR cables like the Belden 1800F? Does higher capacitance result in less resolution and high frequency roll off?
 

DonH56

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I've read reports elsewhere that folks who have used star-quad XLR cables can hear high frequency roll-off, less resolution and overall dullness to the sound. Looking at the cables Benchmark sells for analog connections (Canare L-4E6S), I don't see any roll off until after 20K per Canare's measurements. The star-quad is what Benchmark recommends for both speaker and analog connections.

Are there any measurements that show these characteristics in star-quad cables vs. low capacitance XLR cables like the Belden 1800F? Does higher capacitance result in less resolution and high frequency roll off?

This post shows typical bandwidth for Mogami star-quad cable, very similar to Canare: https://www.audiosciencereview.com/...cable-a-better-cable.21453/page-3#post-712013

The high-frequency rolloff is about a decade above the audio band (300 kHz) for 100' of cable.

HTH - Don
 

RobS

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Thanks Don. Is there a benefit of running a low capacitance XLR cable regardless of length over the star-quads?
 

Docmoggy

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I bought one. I hooked it up to my Brooklyn Bridge DAC and the combo blew my socks off! Was like replacing carburettors with fuel injection. There I was going to get this and that high cost marvel, now its “just get this” it does “that, look at the test results”. I can testify that the Benchmark is worth every penny, although I cannot understand why there is a massive cost difference between the US and UK price - approx $2000. Yes, we in the UK have to pay $2000 more for the same kit. However, at way less half the price of my last mono amps it is a bargain! This is Amir’s point and he is absolutely correct. Hence, I think there is going to be a revolution in HIFI equipment as these tests and their results start being appreciated. This is revolutionary I itself as a consumer champion, indirectly, I feel so stupid for being brand loyal.
 

DonH56

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Thanks Don. Is there a benefit of running a low capacitance XLR cable regardless of length over the star-quads?

Define "regardless of length"... If you are running hundreds or thousands of feet, maybe, but then I think it more likely you'd want the common-mode noise rejection of the star-quad than the lower capacitance cable anyway. I am not seeing a real win here, though if you do not need the noise rejection of star quad then there's no point in paying the extra money for it.

IME/IMO - Don
 

DonH56

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I bought one. I hooked it up to my Brooklyn Bridge DAC and the combo blew my socks off! Was like replacing carburettors with fuel injection. There I was going to get this and that high cost marvel, now its “just get this” it does “that, look at the test results”. I can testify that the Benchmark is worth every penny, although I cannot understand why there is a massive cost difference between the US and UK price - approx $2000. Yes, we in the UK have to pay $2000 more for the same kit. However, at way less half the price of my last mono amps it is a bargain! This is Amir’s point and he is absolutely correct. Hence, I think there is going to be a revolution in HIFI equipment as these tests and their results start being appreciated. This is revolutionary I itself as a consumer champion, indirectly, I feel so stupid for being brand loyal.

Nothing stupid or wrong with being brand loyal to a good brand. Nor in finding a better brand. :)
 

misterdog

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we in the UK have to pay $2000 more for the same kit

If only the US introduced a 20% (VAT) sales tax then they could afford a 'free' healthcare and social system. :)

But the difference is more than that. The UK RRP went from £ 3250 to £ 3500 last march when there was a huge swing in the exchange rate but forgot to drop back when the exchange rate normalised.

Still excellent value for money though.
 

Docmoggy

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I think there is a 20% import tax. Crazy if they add another 20% UK retail VAT on the price. Even so, I wouldn’t put it past the monopolised uk distributor to be making a big margin on the sale. Maybe £1000 per sale. Could be wrong of course. Benchmark would sell a lot more products if amazing products like the AHB2 was at sub £3000 price range. I don’t understand their sales strategy on this. I was looking at the new Cyrus range and it appears to be more of the same. A DAC that retails for £4000 with a £2000 power supply! I mean, that’s crazy. You can get a Topping for less than £1000! That will probably beat the pants off it. I am firmly in the no more mug category - although with the Benchmark I agree, excellent valuse for money but could go into the must have class so easily.
 

Braveanthony

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Hi. Noob question but does a single ahb2 have enough power to drive a pair of 226be? Are they going to be a good match or is the concept of good “match” between amp and speaker also placebo?
I am shopping to for a SS amp to test against my tube setup. Source is tidal wifi i to minidsp shd studio, cheap coax cable to smsl su-8v2 then amazon xlr to amp then bluejeans speaker cables to 226be.
 

DonH56

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"Yes", but it depends upon how far you are from them and how loudly you'd like them to sound.

Online SPL calculator: Peak SPL Calculator
 

RichB

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Hi. Noob question but does a single ahb2 have enough power to drive a pair of 226be? Are they going to be a good match or is the concept of good “match” between amp and speaker also placebo?
I am shopping to for a SS amp to test against my tube setup. Source is tidal wifi i to minidsp shd studio, cheap coax cable to smsl su-8v2 then amazon xlr to amp then bluejeans speaker cables to 226be.

It should not be a problem.
I can post the math later, but according to the Benchmark voltage calculation, you should not have a problem reaching 107 dB at 1 meter per speaker. ,In most rooms, that is 107 dB at the listening position in stereo.

- Rich
 

RobS

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"Yes", but it depends upon how far you are from them and how loudly you'd like them to sound.

Online SPL calculator: Peak SPL Calculator
Problem with this calculator is it doesn't factor in the crest factor of recordings. This calculator tells me I would have 102.8db at my listening position with a 50W amp I used to own and 85db efficient speakers, but it got nowhere near that when the volume was maxed (measured this with a Radioshack SPL meter).
 

RobS

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Hi. Noob question but does a single ahb2 have enough power to drive a pair of 226be? Are they going to be a good match or is the concept of good “match” between amp and speaker also placebo?
I am shopping to for a SS amp to test against my tube setup. Source is tidal wifi i to minidsp shd studio, cheap coax cable to smsl su-8v2 then amazon xlr to amp then bluejeans speaker cables to 226be.
Start with 1 AHB2. If you find you don't have the headroom for transient peaks or it runs out of gas when you increase the volume then you'll need to go monoblock.
 

LarsS

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Hi. Noob question but does a single ahb2 have enough power to drive a pair of 226be? Are they going to be a good match or is the concept of good “match” between amp and speaker also placebo?
I am shopping to for a SS amp to test against my tube setup. Source is tidal wifi i to minidsp shd studio, cheap coax cable to smsl su-8v2 then amazon xlr to amp then bluejeans speaker cables to 226be.

You also need to factor in how much Dirac Live will tax the amplifier. For my use case (bad room) Dirac Live taxed my Purifi amp 9dB (ouch)!
 

DonH56

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Problem with this calculator is it doesn't factor in the crest factor of recordings. This calculator tells me I would have 102.8db at my listening position with a 50W amp I used to own and 85db efficient speakers, but it got nowhere near that when the volume was maxed (measured this with a Radioshack SPL meter).

You have to do that yourself. I tried to ensure I could reproduce 105 dB peaks from my system when I first set things up though my average level is more like 70 dB or so. Crest factor is very tricky and an SPL meter is too slow; for music, the ancient number I remember is 17 dB so a power factor of 50. Movies are more like 20 dB with 30 dB reported for some. I decided a 20 dB crest factor was good enough for me so at 80 dB average (loud for me) if my system can hit 100+ dB using the calculator I am probably good. I figure the very loudest peaks are probably big drum and cymbal crashes or loud explosions/gunshots and I would not notice if they clipped or not. Other folk may like it louder; I have enough hearing issues from too much loud listening and playing on stages to want to crank it like I did when I was an invincible teenager.

The (some) other issues are that the room's influence is not as simple as the calculator would have you believe, and speaker sensitivity is not flat over frequency. That is why I said "rough" -- it is a decent ballpark figure but it takes a lot more work to get it exact.
 

josh358

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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.
Very cool!
 
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