Which power amps (or all of them) have their own sound signatures, and why, by design, or just happened to be?

[PENG]

If you read and believe the linked Audiosciencereview.com review on the Benchmark AHB2, it should be beyond doubt that such an amplifier will just do its job, without introducing any tonal characteristics to the input signal.

The reviewer received two samples. Do you think some golden ears could tell which is which in DBT?

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-ahb2-amp.7628/

 

[HTfreak2004]

I think what most people hear is the noise floor of the amp itself.

A lower noise floor will sound warmer

More noise will sound harsh.

This relates to how clean a speaker is as well. It’s not just an amp that adds to the signal, everything pre amplification does add its own coloration to the signal including wires!

So an amp can obviously introduce some distortion to the sound we hear. Sound by definition is distortion of air movement.

 

[Swerd]

I think what most people hear is the noise floor of the amp itself.

A lower noise floor will sound warmer

More noise will sound harsh.

This relates to how clean a speaker is as well. It’s not just an amp that adds to the signal, everything pre amplification does add its own coloration to the signal including wires!

So an amp can obviously introduce some distortion to the sound we hear. Sound by definition is distortion of air movement.

Your beliefs (marked in bold above) are just what you believe, and only that. They are not fact. They are certainly not fact because you believe them.

All of your statements, however, are testable. Put those beliefs to the test and find out what is actually fact.

I can readily agree with you that speakers also distort sound. It's known that speakers can have quite a lot more distortion, as much as 10% total harmonic distortion, than an amplifier. Amps typically have less than 1% THD, often less than 0.1% THD.

How much distortion has been observed or measured in wires?

 

[PENG]

I think what most people hear is the noise floor of the amp itself.

A lower noise floor will sound warmer

More noise will sound harsh.

This relates to how clean a speaker is as well. It’s not just an amp that adds to the signal, everything pre amplification does add its own coloration to the signal including wires!

So an amp can obviously introduce some distortion to the sound we hear. Sound by definition is distortion of air movement.

Very interesting point, never heard that before.

 

[Kvn_Walker]

Wow I am floored by that one. There's cost and there's value, and I can't foot the bill for that amp, but I have zero doubt that it's worth every penny.

Of course the phrase "you pay for the price" still holds true for some audiofools and they'll buy a lesser amp because this doesn't cost enough.

 

[Swerd]

If you read and believe the linked Audiosciencereview.com review on the Benchmark AHB2, it should be beyond doubt that such an amplifier will just do its job, without introducing any tonal characteristics to the input signal.

The reviewer received two samples. Do you think some golden ears could tell which is which in DBT?

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-ahb2-amp.7628/

I normally stay out of amplifier or other electronic gear discussions. Others, such as yourself, are much better qualified to read & understand reviews like in the link. I don't doubt any of the measurements and gee whiz performance graphs shown in the review; that amp is probably well designed and well made. But is it worth $3000?

I wonder why the reviewer received two samples. Is Benchmark quality control questionable? Did Benchmark intend for the reviewer to keep one? (Yes, I'm cynical.)

To directly answer your question, I am fairly certain that golden ear listeners could not tell which amp is which, if the listening test were done properly. In fact, I'd bet the mortgage that listeners could not tell this Benchmark amp from other well made amps of similar power.

The main reason why I stay away from discussions of home audio electronic gear in general is that they avoid the obvious point, that speakers are where the rubber hits the road. Not amps or other electronic gear.

 

[AcuDefTechGuy]

Auditory Hallucinations are real.

 

[PENG]

I normally stay out of amplifier or other electronic gear discussions. Others, such as yourself, are much better qualified to read & understand reviews like in the link. I don't doubt any of the measurements and gee whiz performance graphs shown in the review; that amp is probably well designed and well made. But is it worth $3000?

I wonder why the reviewer received two samples. Is Benchmark quality control questionable? Did Benchmark intend for the reviewer to keep one? (Yes, I'm cynical.)

To directly answer your question, I am fairly certain that golden ear listeners could not tell which amp is which, if the listening test were done properly. In fact, I'd bet the mortgage that listeners could not tell this Benchmark amp from other well made amps of similar power.

The main reason why I stay away from discussions of home audio electronic gear in general is that they avoid the obvious point, that speakers are where the rubber hits the road. Not amps or other electronic gear.

My golden ear comment was just being sarcastic. Regarding why he received a second one, he said "I requested the second one because of something I was seeing in the measurements that turned out to be my issue, not the amp's."

 

[PENG]

Note that even at the high gain setting, the ABH2's gain is only 23 dB, 6 dB below the more typical 29 dB. That's one reason why the noise spec is so incredible, but it is still outstanding even after factoring in the lower gain.

 

[AcuDefTechGuy]

Note that even at the high gain setting, the ABH2's gain is only 23 dB, 6 dB below the more typical 29 dB. That's one reason why the noise spec is so credible, but it is still outstanding even after factoring in the lower gain.

Wow, I didn't think any amp had that low of a voltage gain.

So if the gain were 29dB like most amps, the SNR would probably be lower?

Not that any of us could actually hear a difference between a SNR of 100dB vs 130dB, unless we're hallucinating.

 

[PENG]

Wow, I didn't think any amp had that low of a voltage gain.

So if the gain were 29dB like most amps, the SNR would probably be lower?

Not that any of us could actually hear a difference between a SNR of 100dB vs 130dB, unless we're hallucinating.

Yep, the table I posted would have to be updated to include 23 dB. For you only, here it is:

Not that bad because it is only rated 100 W, so even the 2 V rated RX-A1020 can make it, barely.

 

[AcuDefTechGuy]

Yep, the table I posted would have to be updated to include 23 dB. For you only, here it is:

View attachment 29589

Not that bad because it is only rated 100 W, so even the 2 V rated RX-A1020 can make it, barely.

Anyone pairing any AVR with a 100WPC Benchmark amp when their AVR could probably output 150WPC?

I just still cannot get over the fact that a $3,000 amp is 100WPC (unless you bridge, which most of us don't recommend).

 

[Irvrobinson]

I wonder why the reviewer received two samples. Is Benchmark quality control questionable? Did Benchmark intend for the reviewer to keep one? (Yes, I'm cynical.)

Benchmark intended the amps to be bridged for systems requiring more than 100 watts/ch, so they wanted them to be tested that way.

 

[Trell]

...
To directly answer your question, I am fairly certain that golden ear listeners could not tell which amp is which, if the listening test were done properly. In fact, I'd bet the mortgage that listeners could not tell this Benchmark amp from other well made amps of similar power.
...

You mean, like if they loose they pay your mortgage and if you win you have to pay it yourself

 

[Trell]

Benchmark intended the amps to be bridged for systems requiring more than 100 watts/ch, so they wanted them to be tested that way.

But then the minimum speaker impedance is 6 ohm, even for stereo bridged output, if I read the following quote correctly. For those with 4 ohm speakers bridging is not a good option with these amps, I guess.

"There is a switch for selecting stereo or mono bridged output. The latter quadruples the amount of power available and unlike typical bridging, according to Benchmark comes at no penalty in distortion! I plan to test this later as it has a minimum impedance of 6 ohm so I could not use the 4 ohm setup I used for this testing."
​

 

[HTfreak2004]

Very interesting point, never heard that before.

 

[PENG]

But then the minimum speaker impedance is 6 ohm, even for stereo bridged output, if I read the following quote correctly. For those with 4 ohm speakers bridging is not a good option with these amps, I guess.

​

"There is a switch for selecting stereo or mono bridged output. The latter quadruples the amount of power available and unlike typical bridging, according to Benchmark comes at no penalty in distortion! I plan to test this later as it has a minimum impedance of 6 ohm so I could not use the 4 ohm setup I used for this testing."​

​

Benchmark also claimed the amp is stable into all loads. So if it is rated 480 W into 6 ohms (nominal), it will have no problem doing 320 W into 4 ohms.

Formula used: Power (for resistor load, R is the resistance) = I^2 * R
Given: 480 W into 6 ohms, so I^2 = 480/6 = 80

Into 6 ohms, power output = I^2 *4, or 80*4 = 320 W.

This amp should be able to output 320 W into 4 ohms, conservatively/safely, when bridged.

 

[Verdinut]

On their website, here is what Benchmark say about the AHB2 power amp:

"Traditional class-AB amplifiers generate crossover distortion every time the push-pull output stage crosses 0 volts. This crossover distortion can be especially problematic at low playback levels.
The AHB2 is the first amplifier to virtually eliminate crossover distortion without incurring the undesirable side effects of class-A amplification."

The fact that crossover distortion is eliminated on a Class AB amp with proper biasing in the output stage is nothing new. It has been done with Class AB amps for many years.

Why do they have to publish marketing bullshit?

 

[KEW]

Why do they have to publish marketing bullshit?

What?
You think its easy to sell 100WPC amps for $3000 each?

 

[PENG]

On their website, here is what Benchmark say about the AHB2 power amp:

"Traditional class-AB amplifiers generate crossover distortion every time the push-pull output stage crosses 0 volts. This crossover distortion can be especially problematic at low playback levels.
The AHB2 is the first amplifier to virtually eliminate crossover distortion without incurring the undesirable side effects of class-A amplification."

The fact that crossover distortion is eliminated on a Class AB amp with proper biasing in the output stage is nothing new. It has been done with Class AB amps for many years.

Why do they have to publish marketing bullshit?

I wouldn't consider that bullshit, just exaggeration like others do. Another example:

"The AHB2 is conservatively rated at an output level where THD+N is < 0.0003 % instead of the more typical 1% THD+N. Power at 1% THD will be higher. "

It is true that other products do quote higher output ratings, at 1% or even 10% THD, but they way BM's website put it is somewhat misleading as even AVR manufactureres, like D&M, Yamaha, Pioneer, Onkyo do provide their output specs at much lower distortions (example: D&M's 4000/7000 series specs say 0.05% 20-20,000 Hz). They simply provide the higher output at higher distortions as well. So Benchmark's "more typical" is misleading, I still wouldn't call it bullshit though.