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Review and Measurements of Benchmark AHB2 Amp

josh358

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Thanks for the reply. Am considering the AHB2 and have heard good things about the A21 and wondered which amp you preferred and why.
Personally, I think form factor, power, and price should be your main consideration. The A21 sounds fuller, AHB2 sounds cleaner (and I'm guessing it's the accurate one). The AHB2's highs are IMO cleaner than the A21's, but I think piano transients are better on the A21 than on the AHB2 and for that matter many other amps I've heard. But as Kal says, the differences are subtle -- I don't think I even noticed the difference in piano attacks until I did a level-matched A/B test.
 

SIY

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Personally, I think form factor, power, and price should be your main consideration. The A21 sounds fuller, AHB2 sounds cleaner (and I'm guessing it's the accurate one). The AHB2's highs are IMO cleaner than the A21's, but I think piano transients are better on the A21 than on the AHB2 and for that matter many other amps I've heard. But as Kal says, the differences are subtle -- I don't think I even noticed the difference in piano attacks until I did a level-matched A/B test.
Any chance of you recording two files, electrically, at the speaker terminals?
 

josh358

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Any chance of you recording two files, electrically, at the speaker terminals?
That's an interesting idea -- it would be interesting to subtract them and listen to the difference. But I just don't have the time to do that now, my good A-D is on ice, the system is biamped, I'd have to level match, etc. so I'm afraid I'll have to bow out. Of course, Kal would be happy to do it. :)
 

SIY

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Nice thing is that @pkane 's excellent software take care of the level matching. I'd like to see if there's a frequency response difference and if the differences hold up to an ABX or similar ears-only test. I just have never seen any of the amp sound claims (absent differences in frequency response or clipping/overload) to ever stand up to controls, so it would be interesting if this one did.
 

pjug

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That's an interesting idea -- it would be interesting to subtract them and listen to the difference. But I just don't have the time to do that now, my good A-D is on ice, the system is biamped, I'd have to level match, etc. so I'm afraid I'll have to bow out. Of course, Kal would be happy to do it. :)
Yes, please do this Kal. Or pass the job to @John Atkinson!
 

pjug

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I don't have the A21 or an ADC, so it ain't possible.
Just joking, but seriously I would like to see someone with good equipment do this. Comparing whatever amps driving whatever speakers. Also, good level matching isn't really necessary. @pkane 's DeltaWave corrects for that.
 

josh358

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Nice thing is that @pkane 's excellent software take care of the level matching. I'd like to see if there's a frequency response difference and if the differences hold up to an ABX or similar ears-only test. I just have never seen any of the amp sound claims (absent differences in frequency response or clipping/overload) to ever stand up to controls, so it would be interesting if this one did.
I'd be curious too. That there are differences is indisputable -- I can identify them on a blind level-matched A/B test. But I'm not sure what they're due to. I recall a study many years ago that suggested that audible differences could be explained by a subtle tilt in frequency response across the spectrum. But I know that John Siau has ABX'd crossover notch distortion, and I've long wondered whether low levels of harmonic distortion are audible under certain circumstances.
 

pma

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Just joking, but seriously I would like to see someone with good equipment do this. Comparing whatever amps driving whatever speakers. Also, good level matching isn't really necessary. @pkane 's DeltaWave corrects for that.

Even the DeltaWave result is better and more reliable if you feed it with level matched and time aligned files. Been there and not only once.
 

pma

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pjug

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OK, please feel free to try my new listening test of 2 different power amplifiers
https://www.audiosciencereview.com/...amplifiers-files-recorded-for-download.25646/
Thanks and I will do ABX and also look at them with DeltaWave. But is this a voltage recording or microphone recording? What I am really hoping for is recording of voltage at the power amplifier output.
Edit: Looking at DeltaWave comparison, it looks like this is in fact a voltage recording? Please confirm. Then we can switch to your thread for discussion.
 
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DonH56

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Thanks and I will do ABX and also look at them with DeltaWave. But is this a voltage recording or microphone recording? What I am really hoping for is recording of voltage at the power amplifier output.
Edit: Looking at DeltaWave comparison, it looks like this is in fact a voltage recording? Please confirm. Then we can switch to your thread for discussion.

Read his other thread; it is the voltage across the speakers, and there is a diagram of the test setup. If the voltage across the speakers is the same, the sound from the speakers must be the same.
 

pjug

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Read his other thread; it is the voltage across the speakers, and there is a diagram of the test setup. If the voltage across the speakers is the same, the sound from the speakers must be the same.
Thanks for heads up. Yes, I asked before that was explained. Now lets discuss in the other thread.
 

Manojrc

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What's the benefits of a LA4 & AHB2 combo over a Pre-amp DAC like RME & AHB2 combo? I have an RME, use it as DAC & pre-amp and consider buying AHB2 and wondering what will be the additional benefit I get if I add LA4 also in the chain. Btw, I've no intention to use multiple souces. Roon->RME will continue to be my only source. So don't want to buy a pre-amp for that purpose ( connecting multiple sources )..
 

josh358

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What's the benefits of a LA4 & AHB2 combo over a Pre-amp DAC like RME & AHB2 combo? I have an RME, use it as DAC & pre-amp and consider buying AHB2 and wondering what will be the additional benefit I get if I add LA4 also in the chain. Btw, I've no intention to use multiple souces. Roon->RME will continue to be my only source. So don't want to buy a pre-amp for that purpose ( connecting multiple sources )..
Don't bother. The LA4 will presumably give you a better signal/noise ratio, but in a home environment, I doubt very much that you'll hear the difference.
 

Vincentponcet

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Probably you can have more gain from LA4 that can exact match the AHB2 low gain mode
RME DAC FS can output at 6.9V (+19dbu) when the ahb2 low gain input sensitivity is at 9.8V (+22dbu), so at max a 3db SNR advantage, but probably should take into account the digital overhead of 2.9db too idk.
 

cany89

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Don't bother. The LA4 will presumably give you a better signal/noise ratio, but in a home environment, I doubt very much that you'll hear the difference.

Why should you have better sound by adding another pre to the system when you already have ADI2?

(Asking it bc I’m in the same situation btw :))
 
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