Let me end the Premp/Amplifier sound debate ...

I have very little concern for those who want to argue against my experiences and choices. 

^Maybe get the moderators to lock the thread^ then?

I cannot argue your experiences, as they are yours.
The choices are also yours.

The reasoning behind those choices, and the “data” that was the basis of that is something that could be argued.

I suppose I have very little concern for you as well. However in theory I have concern for others who would be open to discussion as to how and why we choose the things that we do, and whether there is a good process for doing that.

 

Hey @Holmz

Unfortunately most of those discussions do not actually provide new information, a new perspective, or new methods of evaluation and test. The arguments tend to pool around whether the scientific methods which are in the domain of common hobbyist knowledge are adequate to explain perceived phenomenon. At a certain point you have been in this hobby long enough to know it’s not productive, either in learning something new or in changing minds.

 

I have concern for others who would be open to discussion as to how and why we choose the things that we do, and whether there is a good process for doing that.

And that’s a much better discussion. It’s the listener’s wallet, lifestyle and value system which to me matters most.

^agree^ and well said sir.

@atmasphere nailed it.

And there was a RM video where the fellow that makes test equipment (the one that Amir on ASR uses) was talking about that they need to measure “other things” to correlate what is heard.
So there is some room to go in bringing subjective things into alignment with objective measurements… and that work is on the objective side of things.

@tmaker +1

@toddalin all that plastic on the seat reminds me of Mr Wolf in “Pulp Fiction”.

(Or a crisco party.)
 

FWIW, I've never measured a tube amp output voltage into a loudspeaker that was anywhere close to what an SS amp delivered into the same load... going back to the 70's. Admittedly, it's a small sample, and largely irrelevant as measurements mostly don't mean diddly. 😎

Maybe I am simple fellow… but how can the sound (SPL) be the same, if the current (and voltage) are not the same?

This, on the OP’s leading post, says a lot:

Be true to yourself, but I find very little on earth less worthwhile than having arguments about measurements vs. sound quality and value. 

It is not like measurements are not largely correlated with preferences.
And it is not like engineers aren’t using measurements in the process of design and quality control.

They measure the living $hit out things, and they know which measurements to be doing.
If they were not, and if people did not care, then we would all be running Class-B amps. But people do not usually enjoy crossover distortion, so we have Class-A, tubes, and highly biased class-AB… as well as Class-D.

It does not matter how many measurements we do, people do not enjoy crossover distortion. And that number of people is linear with the pool size of people chosen.

@ieales

There’s much more to sound than SPL.

That snippet you took was out of a response to your post about SS and tube amps not making the same voltage.

Are you saying the voltage is proportional to something other than SPL?
Or what does the voltage of tube versus SS have to do with the sound?

You say that the ear is sensitive to phase. Which speakers are you using and are they providing some well behaved phase response?

@ieales

FWIW, I’ve never measured a tube amp output voltage into a loudspeaker that was anywhere close to what an SS amp delivered into the same load... going back to the 70’s. Admittedly, it’s a small sample, and largely irrelevant as measurements mostly don’t mean diddly. 😎

if the voltage is within, say 10%, then the SPL will be also be very close.

 

Yes it is.

It’s not that the distortion signature is too small, it’s that no one measures it.

BS - it is measured ad naseum, and produces nausea in people that do not understand it.

No SPL meter is going to be better than ±0.1db @ 85dB. It likely has a nonlinear response. In absolute terms, it’s not even close.

BS - most people probably max out at 0.5 to 1 dB difference.
So getting the two systems within a fraction of a dB is a great start to a controlled listening test.

And I further disagree as I have the NIOSH app on my iPad as many low distortion speakers do not sound like they have a lot of SPL happening.
Then when I turn to someone in the room, we have to shout to hear each other… and when I look at the app says 90dB or more.

However on my wife’s old system it sounds loud at 65dB.
On my old system at about 95dB.
And on some state of the art systems mote like 100+ dB before it “SOUNDS” loud.

Back in the 80’s Bob Carver tweaked an amp to sound exactly like another: The Carver Challenge | Stereophile.com

FWIW, we gave up on matched level listening tests in the 70’s simply because it’s about as worthless reading the spec sheet. An amplifier is but one component in a system. Change one thing, change everything. I think it’s stood me in good stead when a guitarist says "Joe Pass is sitting RIGHT THERE!"

I trust Bob Carver about as much as a preacher.

1. He had some good designs, back in the day, but he’s prone to hyperbole and wild eyed ranting.
2. Some of his current designs do not meet specs and appear to be dangerous to safely use.

Other the other hand I have heard only good things about Ralph, and his writing indicates that he is learned in the subject and is rationally presented.

Lastly the use of the word “Synergy” has a magical tone to it, that to me is sort of like a synergy of faults summing to zero.

(IMO) It is easier to build systems were output impedances are low, input impedances are high, the FR and PR is flat… than spicing up bright and warm gear like a sweet-n-sour pork where things are starting out in major conflict.

@mahgister it does not matter how well one treats a room in terms of the direct path sound.
If that sound is filled with distortions, then no amount of room treatments can work by going backwards in time to remove the distortions.

One would hear the direct path sound before any reflections arrive. Whether or not those reflections are high level or super reduced.

While the room may be important, it is not going to fix the amplifier.

 

Try to understand my point without repeating a common place evidence...

A bad electronic design or a corrupted source CANNOT be compensated or repaired by a room acoustic...

Who does not know that? Who? 😁😊😎

Ok @mahgister I get the room stuff, it was just that a lot of the recent posts were on distortion and it being something that differentiates one amp from another.

Sorry that I thought you were tying the acoustic room stuff with the amp distortion.

@ieales 

No mention of calibrated microphone or calibration standard. Both are necessary.

Not in the context of a relative measurement to set levels for comparing things…

And not in the context of understanding that 90dB is 10dB more than the 80dB reading.
Sure it ought be a real 80.5 and 90.76, but who cares… If the music sounds like 70dB but is reading 80+ dB, then I know it is louder than I usually perceive.

Carver made the claim, the Doubting Thomases verified he did what he said he could. 

Personally I would not likely use Carver’s name in an “appeal to authority” based argument.

On a video I saw, his shill also gave me the creeps… it was an unattractive mix of sycophantism and other things. Sort of like a combo of qualudes and whisky seeing those two operate together.

@dain

@holmz your post on different systems sounding loud at different SPL is fascinating and fits my experience too. Listening to a friends system, records and tubes and high efficiency speakers I was shocked it measured 100+ Db but didn’t sound’ loud’. My system can be at 50db and be plenty loud. But I don’t understand that at all. Do you have some insight? Hopefully this is on-topic but so it goes

No insight I would say is objective and provable.

But I think it is about distortion and and higher order harmonics.
@atmasphere mentioned it in the thread about his new class-D amp… maybe on another forum though?

The “quiet loudness” is something I do not hear often. Mostly because I do not hear nice systems too often.
But I like it when they are that way. Seems that “quiet loudness”  is correlated with it being nice sounding generally.

@rauliruegas 

"  to remember Julian Hersch from Audio magazine and his very unscientific view that all amplifiers sounded the same once they met a certain threshold.  Now the site Audio Science Review pushes the same. "

When they have zero distortion, then by definition they will sound the same.
It is doesn’t take a lot of higher order harmonic distortion to sound pretty vile.
And a lot of low order harmonic distortion is hard to identify easily.

If we have one amp with only 2nd order harmonics, and another with only the orders of 3-N…. If their SINAD values are same (not zero), they will sound way  different.

So SINAD becomes most useful when the value is getting towards zero. If it is a long ways from zero, then we have a preference for the type of distortion that is listenable.

Maybe Mr Hirsch was hopeful that the ”certain threshold” was going to arrive sooner?

Dear @holmz : I’m not talking of theory as you and other gentlemans but about what we live day by day and what we listen through our room/systems.
​​​​​​….

Well that Benchmark AHB2 has a SINAD of 120dB.
It is getting down towards the theory side of “close to zero” distortion.

@rauliruegas if you say that they are all sounding different with the same speakers, then I’ll defer to you… as I have not heard them.

Dear @holmz : What you and other technical oriented gentlemans posted here means that if we take the Sansui, the Halcro, the Benchmark and Devialet amps and we listen to all in the same system and even that those four amps are way different whole designs using way different active/passive parts/board material/layout and the like we will listen no difference in the room/system quality performance. Rigth? I know that no one has Zero distortions but all are just really near of that.

I think we would need to A/B those four to make a determination.

As you lead with, “Other technically oriented gentlemen…” then I think in my case that searching for some musical nirvana is an endless game. I am leaning more towards accuracy in signal quality.

Now if the speaker load was purely resistive then a cogent argument might be to choose the lowest distortion amp.

If one has the capability to determine the distortion after the speaker, then the system with the lowest distortion (particularly in the 3rd harmonic and beyond, as well as IMD) would be closer to being high fidelity. Again I am more leaning toward fidelity over a musical flavour.

That said, however, I am running a tube stereo amp at the moment. Which does sound nice.

The gorilla is the speakers, their distortions and resonances, their sometimes difficult to drive loads. I am somewhat under the belief that the passive crossover much of the problem. If we got rid of that we might have less of a phase versus frequency dependency.

However we currently have this mishmash of amps and speakers where we need to find synergy. And this leads us to listening to determine what works. Ideally the speakers would be easy for the amps to drive.

Anyhow, at some point the experience is to listen to music. I have had pretty good results with my first amp (Class-A/B) it was a bit grainy but that might have been the recordings?
The monoblock tube amps that replaced the dead Class-AB were great when they worked.
The current Stereo tube amp sound nice, and I like it in Ultra-Linear versus Triode, which likely says I like harmonics? It does sound good though. (If I could keep the monoblocks working I woudl be using them still.)

I have heard a class-D Purifi powering some smaller speakers and that system was also pretty magical with 125 w/channel.

The whole analogue side is getting an upgrade. It was very nice sounding, and all of it was last millennium stuff. But I want to try low output cartridges and need more phono gain.

These all seem like first world problems, and other than the speakers and subs making huge differences, the rest of the gear, pre and amp(s), are usually more in the category of nuanced to me, than being super obvious.

Well I answered your question truthfully @rauliruegas and I have no practical way to  subjectively listen to every amp, nor to go through every subjective review.

So I go somewhat by others using similar speakers have found to work, as well as using objective measurements to try and exclude gear.

However my last two amp are one that my friend with the Mangaplanners sold to be secondhand.

For Class A, A/B, and D distortion and IMD do give some indication of the quality.
Tubes amp as well, but there are very low performing tube amps that sound nice dues to the distortion profile that Ralph and others have pointed out.

Most people are not likely to mod their amps with different capacitors as the OP had mentioned, so shooting equipment can be a complicated path.

Distortion is measured statically.

Usually it is measured in the frequency domain... rather than statistically.
Time domain measurements are also possible.