Amplifier distortions - what, and how much are audible

[sterling shoote]

I was able to find the SM and OM of the TA-N55ES and it seemed like an excellent amp for its time. You simply pushed it too hard trying to get the best of a big passive subwoofer!! Every time you pushed it pass the 500 W (8 ohms) mark it's only to clip, no doubt about that.. The amp is really only rated 300 W into an 8 ohm load bridged to mono.

The 600 W rating could only be reached (or exceed, for short durations) without clipping if the impedance of the subwoofer happened to be at 4 ohms at that moment. It would be great if you have the impedance/phase angle curve of that JBL B380.

Yeah, I liked the 55 ES amps. As I recall, I had 5 of them and two 80ES amps. Now I have just one 80ES, still powering my sub, and a 5 ch. 9000ES powering my mains, center, and surrounds. At any rate, I am managing the sub for a 5.1 system, as well as two 2.1 systems. For awhile it was a juggling act; but, I think I've finally got a handle on it. The 80ES will be put back into service powering my mains soon and I will be getting a Crown amp to power my sub , as I go from a 5.1 to a 7.1 configuration.

 

[PENG]

Yeah, I liked the 55 ES amps. As I recall, I had 5 of them and two 80ES amps. Now I have just one 80ES, still powering my sub, and a 5 ch. 9000ES powering my mains, center, and surrounds. At any rate, I am managing the sub for a 5.1 system, as well as two 2.1 systems. For awhile it was a juggling act; but, I think I've finally got a handle on it. The 80ES will be put back into service powering my mains soon and I will be getting a Crown amp to power my sub , as I go from a 5.1 to a 7.1 configuration.

For subs, the Crown amps are great. Just thought the very fine Sony power amps can be used for the most demanding speakers if "sound quality" related specs on paper are important.

Take a look:

THD:
0.008% 10 W 4 ohms, 0.004% 8 ohms
0.01% from 20-20,000 Hz from 250 mW to rated output (150 W minimum), both channels driven into 4 ohms
0.05%, 110 W minimum from 250 W to rated output.

IMD:
0.008% at rated output, 4 ohms
0.004% at rated output, 8 ohms

Slew rate:
120 V/usec

These amps were clearly designed to perform a little better with 4 ohm loads. Fantastic slew rate spec whether that makes a difference or not.

 

[lovinthehd]

How Loud is the Distortion and Noise from Your Amplifier?

What's with the silly capitalization of letters? What's a summary of the video? Or do you not really understand this like so many other things?

 

[TankTop5]

What about dynamic range? Obviously it’s irrelevant for most media sources beyond maybe 16 bits

 

[PENG]

What about dynamic range? Obviously it’s irrelevant for most media sources beyond maybe 16 bits

That's practically irrelevant too if your amp has excellent SNR, or as described in this video, very quiet amplifier. Yes 16 bits (such as the CD spec) should be transparent enough for all intense and purposes.

 

[PENG]

John Siau's video, and I watched quite a few, are typically very good for people with basic EE principles related to this hobby but they also could mislead (of course unintentionally) a lot of people if they don't watch the whole thing, preferably at least twice.

As @lovinthehd alluded to..., one has to understand........ For example, one of the take aways for me is that people who might focus on power amps, could almost do better by focussing on the room and speakers more, based on audible sound quality benefits. In terms of objective measurements, in absolute term, class D amps such as Hypex, Purifi, and some ICE based amps such as Marantz Amp 10, 20, and other well measured ones, along with Benchmark's class AB amp, namely the AHB2 are going to be among the top picks that mostly have noise/distortions below the audible threshold when used at well below their rated limits, but not something like the Parasound Halo models regardless of the fact that even Gene and John may not likely hear a difference in a DBT AB comparison between the worst and best power amps mentioned in this video.

Also for example, the high level of noise/distortions for the worst amp at 100 W output level would not likely be of concerns for most people if we keep in mind that for speakers with sensitivity above 85 dB, at say 12 ft, will produce 79 dB SPL with just 1 W, that's not that great for people who listen to reference level for sure, but in that scenario, "masking" will save the day anyway, rendering such a concern practically unnecessary, no wonder I spent so much time in room correction/eq and always keep an eye or known media contents that has excellent recording/mastering quality.

 

[PENG]

How Loud is the Distortion and Noise from Your Amplifier?

That's an excellent video to add to the links posted on this thread, totally relevant, thank you very much. I wish I could add it to the first page.

I have to agree with HD though, that people (surely not you and him) might not understand enough to interpret the whole contents/messages they might try to convey, without a more clearly worded conclusions (even if certain points made might be necessarily inconclusive).

 

[Speedskater]

What's with the silly capitalization of letters? What's a summary of the video? Or do you not really understand this like so many other things?

From AI:
In title case, you typically capitalize the first and last words, and all other major words in a title. This includes nouns, pronouns, verbs, adjectives, and adverbs. Minor words like articles (a, an, the), prepositions (in, on, at), and conjunctions (and, but, or) are usually lowercase unless they are the first or last word of the title, or if they follow a colon.

 

[AcuDefTechGuy]

Here's my take-away: If you use a washing machine in the forest and there is no one around to hear it, does it still make a sound?

If an amp makes a 35dB snake-hissing noise at 100W producing 100dB of music, can you still hear the 35dB snake-hissing noise in the background?

Well, like anything else, it doesn't matter because you can do whatever you want with your money.

If you want to spend thousands of dollars on amps to get -10dB sound, you can do that.

If you would rather spend that extra money on other things, you can do that.

We all have different priorities.

 

[PENG]

Here's my take-away: If you use a washing machine in the forest and there is no one around to hear it, does it still make a sound?

If an amp makes a 35dB snake-hissing noise at 100W producing 100dB of music, can you still hear the 35dB snake-hissing noise in the background?

Well, like anything else, it doesn't matter because you can do whatever you want with your money.

If you want to spend thousands of dollars on amps to get -10dB sound, you can do that.

If you would rather spend that extra money on other things, you can do that.

We all have different priorities.

Well said, you could have helped Gene and John do a "better" job in terms of summary and conclusions. I assume John was trying hard to make his point, but in doing so, like the louder than washing machine thing, was one example of what I suspected as potentially a reason why some people might be mislead.

He did list some good reasons why people would still go for amps that have specs that put them in the well below threshold of audibility in terms of SINAD, but again, some people would have to watch the whole thing till the end, and have some basic technical knowledge.

I would agree with PaulBe that EE degree is not a prerequisite, but just some basic EE principles and hobby related technical knowledge would help in interpreting things they explained, without ending up misunderstanding some of the concepts.

 

[AcuDefTechGuy]

Another thing that is misleading is the actual noise levels of appliances since there is no measurement STANDARD. So these companies could just say whatever they want within the "ballpark".

Just because a washer is spec at "40dB" doesn't mean it is truly "40dB from 1 meter away". In reality, it could be 80dB from 1 meter away, but 40dB from 4 meters away.

So when an amp is making the hissing sound through the speaker, is it at 1 meter away?

The other issue is the pitch (frequency of the noise). Washers are not making "hissing" noises like speakers/amps. Washers are making really loud annoying noises that could be a lot higher in pitch.

IOW, are we really comparing apples to apples?

 

[Verdinut]

The other issue is the pitch (frequency of the noise). Washers are not making "hissing" noises like speakers/amps. Washers are making really loud annoying noises that could be a lot higher in pitch.

They are making a lot of annoying noises, We are actually missing the low noise of 1970-80's Maytag machines.

 

[PENG]

They are making a lot of annoying noises, We are actually missing the low noise of 1970-80's Maytag machines.

If noise is the concern, I would go with Miele, or Bosch, that is more affordable.

 

[lovinthehd]

From AI:
In title case, you typically capitalize the first and last words, and all other major words in a title. This includes nouns, pronouns, verbs, adjectives, and adverbs. Minor words like articles (a, an, the), prepositions (in, on, at), and conjunctions (and, but, or) are usually lowercase unless they are the first or last word of the title, or if they follow a colon.

It wasn't presented as a title/quote....but Paul is kinda slow.

 

[lovinthehd]

The capitalization is just the copied and pasted title. What is so silly about this? Isn't this thread the "Amplifier distortions - what, and how much are audible" thread? Summary: 'Amplifier distortions - what, and how much are audible', is what Gene and John are talking about. Do you not understand this from the title itself? This is a new video from 4 days ago. Did I add this video interview to the wrong thread?

Copying and pasting and presenting as your own words, yeah, kinda silly. You are kinda slow, tho.

 

[PENG]

John Siau is saying nothing except that amp distortions can rise to a dB level consistent with home appliance noise, when using otherwise excellent equipment. Does anyone here think he meant that the distortion will sound like a washing machine?

The point is, what is the point then? The fact is, we can all hear our washing machines loud and clear anywhere in a small to medium size room/house (say 2000 sq.ft), but we can't hear the Parasound A21+ amp's noise except listening to close to reference level during the quiet to almost completely silent passages such as in between movements in a violin concerto? So, okay he's right in saying what he's saying, but there's not much point saying it when it actually have the outside chance of misleading people, again not someone like you who are obviously very experienced and knowledgeable in the related topics.

Perhaps the best thing to do is audition one of his AHB2 amps and listen for ourselves instead of being so critical of his presentation – a presentation attempt meant for audiophile consumption.

I have to respectfully disagree, audiophiles likely wouldn't care as lots of them, even the majority I would guess, usually just go by what they thought they heard, without thinking much about Oh, I heard the snake hiss that ADTG talked bout, every time there's a momentary peak pushing near 105 dB SPL in the contents I listened to.

Also, I don't think anyone (that is anyone who under the basic related/applicable theories and principles..) need to his AHB2 amp to appreciate how quiet/silent that amp would be when used for even listening to pure tones at well below it's clipping level.

Benchmark’s AHB2 amps hit all the real audio checkboxes, in a small efficient form. If you don’t like what you hear through it, you don’t like the source recording or something in the chain before or after the AHB2 amp.

I am not sure it you think anyone would disagree with you on this lol..

The comparison is amp to amp. The topic is "Amplifier distortions - what, and how much are audible". We are still measuring things that matter less, and avoiding measuring things that matter more.

Totally agreed, I wish there are good ways to measure the audibility of different audible sound quality due to different recording/mastering quality in quantifiable ways, but even in subjective ways would be nice. I don't want them to stop measuring SINAD, but when we are dealing with the kind of amps JS mentioned in the video, the quality of recording/mastering will, imo have much more audible effects as related to enjoyability.

This is getting more interesting than worrying about phase, so I hope you are not ready to revert to "I am done on this topic"

By the way, I too, am a believer in the AHB2 being among the best in terms of transparency, especially if two are used for 2 channel stereo in bridge mode. My own wish is if he would do a better job on slew rate in the upcoming version, I have no doubt the specified slew rate as it is now is more than high enough, but it is far from SOTA, yet it's specified SINAD is definitely SOTA, second or third to may be a few class D amps (based on measurements found on ASR, or probably Stereophile, or SoundStage Hifi too but not sure.

 

[PENG]

What is special about the AHB2 in bridge mode other than more power? I use one AHB2 for each bi-amped floor speaker - One channel for woof; The other channel for tweet; Bi-amped mono blocks.

Just higher voltage output, I always prefer to have much more headroom that I actually think I need, for the peaks/transients in contents I might listen to.

What is wrong with the slew rate with the AHB2? It has a bandwidth that exceeds any amp I remember; from the bottom to the top; with perhaps an exception for some Nelson Pass designs. Any band limited class D amp has lower slew rate, though some have incredibly good low frequency response.

I did not say or thought there's something wrong. Like headroom, I simply want more, higher in this case.

Do you have a reference for the upcoming version? I didn't know a new version is being made. Or, are you stating you would like better slew rate in any new version.

I am just hoping they are working on a new version, that offers even better specs, knowing that better specs will just be "better relatively speaking", not audibly better. The same goes for distortions, noise, frequency response etc.etc., like DACs, resistor tolerances, better specs typically result in higher costs, why would people like me still want them and willing to pay more would be the question, and John Siau did provide something on that near the end the video.

When I read reviews in pop audiophile magazines, I read between the lines. IMO it is rare that reviewers really understand what they are writing. Most reviewers are dilettantes.

I said something to that effect in the beginning....

Terms like SINAD are functional, yet incomplete. I don't have a substitute or addition. Alas, we use what we have.

I actually would like to see distortions and noise measured separately, but it is easier to measure SINAD, and as you said SINAD is functional, highly functionally imo.

 

[AcuDefTechGuy]

John Siau is saying nothing except that amp distortions can rise to a dB level consistent with home appliance noise, when using otherwise excellent equipment. Does anyone here think he meant that the distortion will sound like a washing machine?

Perhaps the best thing to do is audition one of his AHB2 amps and listen for ourselves instead of being so critical of his presentation – a presentation attempt meant for audiophile consumption.

Benchmark’s AHB2 amps hit all the real audio checkboxes, in a small efficient form. If you don’t like what you hear through it, you don’t like the source recording or something in the chain before or after the AHB2 amp.

The comparison is amp to amp. The topic is "Amplifier distortions - what, and how much are audible". We are still measuring things that matter less, and avoiding measuring things that matter more.

Let’s not even talk about amps for a minute.

If you say a speaker has distortion noise of 40dB and tell people repeatedly that a washer also has a noise of 40dB, many people are going to think this speaker sounds as loud as a washer.

That’s how advertising works. This is what they mean by “misleading”.

 

[AcuDefTechGuy]

Perhaps John Siau will develop a more satisfying comparison.

All he has to say is, “At 100W this amp can produce a hissing noise of 40dB from the speaker from 1 meter distance if there is no other sound playing at the same time”.

 

[Trell]

Perhaps the best thing to do is audition one of his AHB2 amps and listen for ourselves instead of being so critical of his presentation – a presentation attempt meant for audiophile consumption.

Listen to this amp?

Here is a review with many measurements:

Review and Measurements of Benchmark AHB2 Amp

This is a review and detailed measurements of the Benchmark AHB2 Amplifier using THX technology to reduce distortion. I was going to request one for testing due to membership demand but to my pleasant surprise, the company volunteered to contact me and send not one, but two units! I requested...

www.audiosciencereview.com