Do all amplifiers sound the same? Level matched listening test

[IPunchCholla]

Don't ask me - I'm not an amplifier designer.

Don't tell me that an amp designed doesn't ask people to listen to and comment on its sound before they release it on the general public. Beta testing, etc

If you can't tell a great sounding amp from a good sounding one, get your hearing fixed, rather than look at measurement to offer the answer.

I’ve tested my hearing for FR response, harmonic distortion sensitivity, and noise sensitivity. I know within a few dB how much of any of it I can hear. And I can’t hear the difference between my ADA 150 and PA5. I can hear a difference between my speakers in different rooms and between different speakers in the same room. And every difference is accounted for when I measure.

As a producer of music I have tricked myself into hearing differences when there are none (adjusting volume on tracks that were muted, adjusting the volume on a sub that was off). I know I can be trivially misled by my senses if I don’t apply rational checks on them.

When I joined this site, I didn’t know ohms law. Since then I have learned enough to design electronics and build them. But you don’t even have to go that far. There is free software that lets you build any electric circuit you want and pretty much every component is modeled for download for free. I have now designed and simulated class A and A/B amps. It really didn’t take too long to learn.

In the process what I found out was there is no mystery to any of this on the electronics side. It’s a totally solved problem. Everything that goes into an amp is understood far, far, far past humans ability to hear.

Claiming you can hear things that can’t be measured in an amp circuit is like saying you can see further than the Webb telescope.

It needs extraordinary evidence, not just a simple, “because I said so.”

 

[Cbdb2]

Don't ask me - I'm not an amplifier designer.

No kidding. Or any other electronics.

Don't tell me that an amp designed doesn't ask people to listen to and comment on its sound before they release it on the general public. Beta testing, etc

Yea because they want a bunch of different opinions that are imagined by people who think they have super hearing but cant pass a simple AB test. Sound familiar?

 

[IPunchCholla]

Try foobar2000

foobar2000 for Mac

foobar2000

www.foobar2000.org

They have an ABX comparator plugin:

https://www.foobar2000.org/downloads/foo_abx-mac.fb2k-component

Thank you! Last time I checked (I guess it must have been before January of this year), the ABX component wasn't available. Now it is and works great.

 

[IPunchCholla]

Big no difference for me.

foo_abx 2.2.3 report
foobar2000 v2.25
0125-09-01 12:55:42

File A: amp_X.wav
SHA1: c60451229fba3a73fc22f6156b9ed9490072ff8f
File B: amp_Y.wav
SHA1: 70bc370670bdfe1bbedd5ffb635634cef04ff6e6

Output:
Core Audio : Default, 16-bit
Crossfading: NO

12:55:42 : Test started.
12:56:39 : Test restarted.
12:56:39 : 00/01
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12:57:09 : 00/02
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12:58:03 : 09/16
12:58:03 : Test finished.

----------
Total: 9/16
p-value: 0.4018 (40.18%)

-- signature --
24444ef5e67da3fa56b3a4919c52b426c94f9313

 

[Groove01]

Don't ask me - I'm not an amplifier designer.

Don't tell me that an amp designed doesn't ask people to listen to and comment on its sound before they release it on the general public. Beta testing, etc

If you can't tell a great sounding amp from a good sounding one, get your hearing fixed, rather than look at measurement to offer the answer.

I’m going to hazard a response here. I am not a measurement purest in that I’m not buying speakers based on measurements alone - lol. I do however believe good measurements are table stakes and that similarly measuring amps will sound equally similar under similar tested conditions. I think logic dictates as such.

That said, this is where I might stray from the pack. I am not convinced that all similarly measuring amps “perform” equally well under real life conditions with demanding loads/speakers and source material. (I think this can also be measured as well, but may or may not be fully represented in all cases. I could be mistaken though)

I’ve tried to start thinking in terms of which amp(s) will perform well within my system parameters. Measurements can help me achieve that much more efficiently and narrow the field to suitable options.

I can then make any trade off decisions in a rational and informed manner. (Although my final decision may or may not be fiscally responsible - )

 

[IPunchCholla]

I am not convinced that all similarly measuring amps “perform” equally well under real life conditions with demanding loads/speakers and source material.

Demanding loads are part of the measurements of amps now. Not sure if they have been for long enough to get a sense of if they are revealing anything new.

What do you mean by demanding source material?

 

[Hear Here]

edit - @Sal1950 beat me to it, but my comments below stand I feel -

You've got yourself used to SET amps, which by all accounts over the years, massively distort and are usually rather low powered I seem to recall, so almost certainly imparting a 'sonic flavour' to your reproduced sound at home you appear to like very much!

Now, take out your SET amp(s) and replace with a basically non-distorting (into any reasonable load) Benchmark and *of course* you'll hear that something is missing - I'd expect nothing less. Your preference for the SET is akin I suspect to me liking milk and sweetening in my tea (it took me a while to go from semi-skimmed milk to skimmed - and then back again when I married), or putting a mixer with a half decent whisky that's refined enough on its own to be drunk as-is

We in the UK 'flat earth fraternity, used to like hideous-response speakers (little deep bass, 'projected' vocals and poor tweeter crossover implementation which we then balanced with a dull fruity-bass vinyl source. Change the vinyl source to 'digital' and the sound became relentless and screaming - do any other oldies here remember this? Step forwards to today and try the very same CD discs on a now vintage player into a properly balanced system- and the 'sound' is absolutely fine! No wonder the flatter-measuring speakers of the early 80s weren't liked in comparison with the peaked-up 'two maker' systems we loved in our mis-spent youth, as they were deemed boring and lifeless in comparison with the domesticated PA amps and speakers we loved back then

It'll be a difficult 'cure' for someone like yourself I suspect. These days, I'd not know where to start, but it could begin with gaining a little knowledge of psycho-acoustics I'd suggest. I did something with my rig a couple of months ago which by my own reckoning should have made the sound more 'clinical' and 'bass light,' yet when I didn't have much time and switched the rig on, stuck a disc quickly in the player to enjoy a particular piece of music, I had bass, I had a sweet enough top and a good helping of 3-D as well, as much as my gash old system can manage. I was aghast when I looked to confirm which amp was playing, as I'd completely forgotten which it was. So much for pre-conceived ideas formed previously by sighted listening at random volumes.

That's my take anyway, for what it's worth

I recognise much of what you say, including a switch from SETs to a Benchmark amp may come as a bit of a shock. Yes, SETs feature harmonics that are generally considered to be attractive to the human ear - and that in itself is a pretty good reason for using SETs if the speakers are sensitive enough to cope with their low output. My speakers at the time were 101 dB (my present ones are claimed to be 107 dB), so they needed very few watts to provide sufficient volume to disturb the neighbours! Not all SETs sound the same and not all ss amps sound the same - far from it, as I discovered. My favourites SETswere the 6 watt PX-25 from Art Audio and the beefier 845s from Art Audio and later Opera Consonance’s monos.

After retirement, when I anticipated many more hours of music listening, I decided to move to ss, but only if the sound was equally satisfying or better than the SETs, but without trying to mimic their sound.

Over more than a year, I bought or borrowed many ss amps and there is absolutely no doubt that their sound varied quite considerably. Some sounded such that I was inclined to turn down the volume - kiss of death as far as I'm concerned - while others invited me to turn it up and wallow in the sound they allowed my speakers to deliver.

It certainly was never an SET one day and the Benchmark (or any other amp) the next. Some were kept for a week or so (the dealer loans) and others for a few months (including the Benchmark) and others still for over a year, including a GamuT D200 and Accuphase A-36. This gave me and friends who regularly visited to listen with me, the opportunity to judge the dull and boring delivery of some of the amps, and to relish in the excitement / tingle-factor that others delivered.

If a bit of distortion improves the listening experience, then bring it on! If zero distortion leads to the delivery of Muzak, then it's going back to the dealer with a polite "thanks for the loan" note.

Frankly I don't give a dam about how an amp measures as long as it excites me such that I'm inclined to turn up the volume, rather than turn it down. Ones that achieved this were the Gamut D200, the NAD M33, the Accuphase (though perhaps a little too polite), a Mark Levinson (that was beaten by others at lower price) and a Micromega that was perhaps just a little too "French"!

Ones that failed early on but were the otherwise very desirable included Benchmark, a Sugden (now unsurprisingly discontinued), a Quad and a Lyngdorf so beloved of one particular forum's membership.

I'm still very content with my chosen Class D amplifiers - one from a big brand and the other from a well-respected valve amp builder who has seen the light and is now building exceptional D amps. I would happily switch to other Classes or brands if I found one that significantly out-performed my present amps.

Anyone who buys an amp based solely on its measurements is doing himself a dis-service as one really needs to listen at home to a variety of amps to see which works best in his room with his speakers.

 

[Groove01]

What do you mean by demanding source material?

I was referring to demanding musical passages (peak transients), etc. Classical music for example

 

[IPunchCholla]

I was referring to demanding musical passages (peak transients), etc. Classical music for example

Ok. But the only measurement you need for that is the power before clipping across a sample of frequencies. That is presented in every review. Then it is just a matter of your speaker sensitivity and loudest listening level.

Edit to add: assuming both amps are flat in the FR across the audible range.

 

[DVinylfan]

and a Micromega that was perhaps just a little too "French"!

BS like this is what the 'ignore' button was invented for.
Hear Here? Bye Bye.

 

[Sokel]

Demanding loads are part of the measurements of amps now. Not sure if they have been for long enough to get a sense of if they are revealing anything new.

What do you mean by demanding source material?

It's not only about loads.

One of the recent Amir's test has probably went under the radar. And it's of the simple ones, no one needs to understand charts to see what's going on.

Look at this for example.


Look at the Max and Peak Power at the standard test:

Nice 230W.

Now look the max power at 40Hz:

I would say about 180-190W?
And that's at 40Hz, not 30Hz or 20Hz.

Others get a worst penalty.

Moreover, is where power is needed the most and if (God forbid) someone corrects for room down there filling dip situation can skyrocket.
I have seen perfectly adequate on paper amps having huge difference in lows distortion just because of their power (class, etc all the same, even the brand! )

 

[Sal1950]

So the bad part is that apms clipping brought major distortion to speakers, sounding like they are tearing apart, and then eventually the amp shouts down - that was at full volume. When we replaced them with Crown 2kW amps things were back in business. Not sure how the speakers survived that power, but they serve well to this day.

Poor little speakers

edit - @Sal1950 beat me to it, but my comments below stand I feel -

Excellent, tackful post, better than I could assemble.

Don't ask me - I'm not an amplifier designer.
Don't tell me that an amp designed doesn't ask people to listen to and comment on its sound before they release it on the general public. Beta testing, etc
If you can't tell a great sounding amp from a good sounding one, get your hearing fixed, rather than look at measurement to offer the answer.

I can tell you they spend much more time reviewing the measurements, making small changes in attempts to improve the the amps functioning from a scientific angle. Most designers (contrary to what their marketing ad writer publish in the magazines) know the amp will sound the way they want it too IF it measures right.
There are only a few designers that built for a particular sound, your SET guy is probably one of them. He's not looking for it to sound like what was created at the mixing engineers console or what the artist intended. He wants it to sound like what he thinks it should, that specially distorted sound his gear is known for. Only problem there is that he's NOT the musician, his job is to let you hear what the musician created, not his idea of that.

 

[Digital_Thor]

I had a LAT500 subwoofer. I thought a Vincent SAV P200 was powerful enough for this. But it always very easily bottomed out before it got loud enough.
After I switched to a bigger class H amplifier - I used the subwoofer with great pleasure for a few years, before it got sold, and during this time, it played much better - no bottom out. You could easily see how the membranes in the LAT500 "flapped" with less control with the Vincent, while the class H amplifier kept the membranes firmly in place. Weird spectacle to behold. At that time, I could only guess that the Vincent had terrible damping factor, or the LAT500 was a menace to drive.
Same line level DSP and setup - amplifier directly connected to the LAT500.
This is one of the few times, where I could actually hear a proper difference. But to me, this makes sense, because we are talking about driving a subwoofer unit to its max.
For normal listening - I can't hear a difference between my current 200W AB and a NC502MP.

 

[Oddball]

It's not only about loads.

One of the recent Amir's test has probably went under the radar. And it's of the simple ones, no one needs to understand charts to see what's going on.

Look at this for example.


Look at the Max and Peak Power at the standard test:


View attachment 473620

Nice 230W.

Now look the max power at 40Hz:

View attachment 473621

I would say about 180-190W?
And that's at 40Hz, not 30Hz or 20Hz.

Others get a worst penalty.

Moreover, is where power is needed the most and if (God forbid) someone corrects for room down there filling dip situation can skyrocket.
I have seen perfectly adequate on paper amps having huge difference in lows distortion just because of their power (class, etc all the same, even the brand! )

I have been trying to clip my modest Rotels 1070 but not really having much luck (except in extreme circumstances noted above).

'Rotel RB-1070 Amplifier Review'

Jan 21, 2023

This is a review and detailed measurements of the Rotel RB-1070 stereo power amplifier. It was released in early 2000. Can't find the cost then but I see it used for around $400 to $500.

I have always found Rotels to be most attractively designed power amplifiers. One look at that front panel and you immediately think of muscle and beauty in design. Alas, the extruded aluminum in front which gives it that look, is cosmetic. There are two others internally which do the job of cooling this classic AB design. In use the heastsinks got pretty warm to touch to give it some air...

• amirm
• Replies: 254
• Forum: Stereo and Multichannel Amplifier Reviews

• 

Even if I put in 10dB of headroom expansion in the Audy app, they just keep it going without clipping. This is for surrounds. LCR are on Brystons and they don't really care if 10dB or more. 10dB is too much for regular use as puts lots of strain on the speakers but this is just to show what amps can or can or can not do not to.

Obviously, not all amps are the same once you use them in the real world.

 

[Sal1950]

That said, this is where I might stray from the pack. I am not convinced that all similarly measuring amps “perform” equally well under real life conditions with demanding loads/speakers and source material. (I think this can also be measured as well, but may or may not be fully represented in all cases. I could be mistaken though)

I think you are and may not have paid close enough attention to my earlier copy and paste of Peter Aczels quite old statement.
Now at first glace this may seem very simple but would take quite a bit of time and attention to the amp-speaker interface. It's quite a bit more detailed than just "similarly measuring amps" I'll post it one more time, take a bit to review and think about what it would require and reveal.

 

[IPunchCholla]

It's not only about loads.

One of the recent Amir's test has probably went under the radar. And it's of the simple ones, no one needs to understand charts to see what's going on.

Look at this for example.


Look at the Max and Peak Power at the standard test:


View attachment 473620

Nice 230W.

Now look the max power at 40Hz:

View attachment 473621

I would say about 180-190W?
And that's at 40Hz, not 30Hz or 20Hz.

Others get a worst penalty.

Moreover, is where power is needed the most and if (God forbid) someone corrects for room down there filling dip situation can skyrocket.
I have seen perfectly adequate on paper amps having huge difference in lows distortion just because of their power (class, etc all the same, even the brand! )

Sure. But that difference is 2dB. I’ll have to test if I can hear that with music, but it isn’t really a huge difference and will only be apparent when playing the amplifier at max power?

 

[Groove01]

Then it is just a matter of your speaker sensitivity and loudest listening level.

Agree, I think we are saying the same thing. Perhaps a better phrasing for my thought would have been:

Amplifiers measuring equally transparent will be sonically materially similar. They’ll sound the same. However, not all transparently measuring amps are equally fit for all purposes.

 

[Sokel]

Sure. But that difference is 2dB. I’ll have to test if I can hear that with music, but it isn’t really a huge difference and will only be apparent when playing the amplifier at max power?

If chosen tight for a task, is really easy to max out with every beat.
And what if it's proportional?
If chosen adequately for every given situation down the road, with thermals and everything at check I suppose that the difference could be not as significant.

But at the end of the say, why? It's cleary a compromise, and a big one. There are amps that would pass this with flying colors.
What I would call a good amp apart from reliable, decent gain and power, is one that's invariant under any condition, be it power, load, frequency, etc.

 

[Cbdb2]

Micromega that was perhaps just a little too "French"!

Wow.

It's not only about loads.

One of the recent Amir's test has probably went under the radar. And it's of the simple ones, no one needs to understand charts to see what's going on.

Look at this for example.


Look at the Max and Peak Power at the standard test:


View attachment 473620

Nice 230W.

Now look the max power at 40Hz:

View attachment 473621

I would say about 180-190W?
And that's at 40Hz, not 30Hz or 20Hz.

Others get a worst penalty.

Moreover, is where power is needed the most and if (God forbid) someone corrects for room down there filling dip situation can skyrocket.
I have seen perfectly adequate on paper amps having huge difference in lows distortion just because of their power (class, etc all the same, even the brand! )

Thats less than 2db differance. Music is full bandwidth, no one listens to 40hz tones. Whats the max power with pink noise?

 

[Sokel]

Whats the max power with pink noise?

That's a test I keep asking for, preferably one that doesn't last a few ms.
Spectrum is additive and we keep forgetting that.