Stereophile's Jim Austin disagrees w Atkinson; says tubes have something that can't be measured

[Cbdb2]

If we consider whether it is possible to measure something, we must define what are we measuring.

Regarding distortion, which is a non linear phenomenon, the plot thickens a lot.

You can quote a distortion figure in percentage for an amplifier. You must quote the frequency of the signal being measured (ok, we assume a sinusoid), its level, and we obtain a figure. A figure is a single dimension. How much information can a single figure portray?

Two different pieces of equipment with the same measured frequency response and distortion can sound radically different.

What is the harmonic content of that distortion, it, its spectrum?

How does it vary with level?

How does it vary with signal frequency assuming a sinusoid?

Do other complex products such as intermodulation appear when we are not playing a humble sinusoid but real music?

So, you can measure it. But good luck trying to obtain a measurement that can really characterise it in a useful way.

What is a useful way? Well, let's imagine that we devise a way to measure and characterise that somehow yields a vector magnitude such that two different pieces of equipment with the same "distortion vector" sound "the same".

And that's the problem. When recording music (except classical) it's not uncommon (especially for voices) to choose microphones that have a valve preamplifier that distorts a bit when pushed hard. And some of the coveted mastering equipment, especialy passive equalisers and dynamic compressors, do distort in a pleasant way. Or a way that most people will consider pleasant.

For dynamics processors you could boldly say that they "macro distort" (applying compression or limiting to a signal is non linear distortion) and also "micro distort" (inherent distortion to the components and circuit path unrelated to the settings applied on the control panel such as ratio, make-up, attack and release times, etc).

There's nothing wrong about it. We use our audio equipment to play music, not to reproduce laboratory measurements.

Is there anything wrong about the measurement first approach in fhis forum? Of course not at all, I am not claiming that. There is some performance any good piece of equipment must satisfy not to be considered junk. But beyond that some designers can make some adjustments in order to obtain that "something else".

When photography was invented I guess some people thought it would be a guarantee of absolute truth. That said, no matter how faithful photography is, just by composing a frame you are deciding how you want reality to look like. When recording music you choose microphones and their placement.

When mixing and mastering you make tons of decisions about equalization (which can be corrective or somewhat creative) and surely you will tweak dynamics. You can do it in an obvious, blatant, creative way, or you can be subtle and do it in a way that people won't notice. But you are altering reality.

You can measure (and hear) all the distortion by subtracting the input from the output. The difference is just the distortion. Studio gear has little similarity to home audio.

 

[Cbdb2]

What I don't understand is why people read those rags.

 

[Sgt. Ear Ache]

Sure. Or they do something audible.

I'm not sure I understand. Has anyone anywhere claimed that tone controls don't make an audible difference?

 

[fpitas]

What I don't understand is why people read those rags.

Just from the little I've read, some seem to be fascinated by the expensive stuff. Like it must be good somehow.

 

[solderdude]

You can measure (and hear) all the distortion by subtracting the input from the output. The difference is just the distortion.

Weeeeelllll... when you do that and there is a bit of phase shifting or time delay, which might not be audible, that phase shift (+ the distortion) and maybe time delay comes out as an amplitude difference which may lead to a difference signal that is not truly the difference signal (when listening to it). It can be quite clear when analyzing input, output and diff signal.
Works great with cables though.

 

[Zensō]

Do you care at all about how any of your other equipment looks? For instance do you care what your speakers look like?

Sort of. Obviously, I don’t want my monitors to be painted pink or fluorescent chartreuse, but if they’re reasonably neutral and not outlandish in some way, that’s good enough for me. Prioritizing looks when purchasing audio equipment seems like a fool’s errand to me personally, but to each his own.

 

[Cbdb2]

Weeeeelllll... when you do that and there is a bit of phase shifting or time delay, which might not be audible, that phase shift (+ the distortion) and maybe time delay comes out as an amplitude difference which may lead to a difference signal that is not truly the difference signal (when listening to it). It can be quite clear when analyzing input, output and diff signal.
Works great with cables though.

I didn't say it was easy, but its possible.

 

[MattHooper]

How will we know?

This being ASR, the answer would be obvious - examining what if anything was done with the circuits of those knobs, measurements, blind test - so I presume you were channeling Jim Austin there?

 

[MattHooper]

Sort of. Obviously, I don’t want my monitors to be painted pink or fluorescent chartreuse, but if they’re reasonably neutral and not outlandish in some way, that’s good enough for me. Prioritizing looks when purchasing audio equipment seems like a fool’s errand to me personally, but to each his own.

Ok, understood. I am very aware there are audiophiles who generally don't care how equipment looks (and to my eyes, the visuals of their set-ups tend to advertise this).

If by "prioritizing looks" you mean buying only on looks or looks well above all else - as in "who cares much how this sounds, I like the looks" - I don't think many audiophiles fall in to that category.

But if you mean prioritizing looks - taking aesthetics in to account along with the sonics - is a fool's errand, there is such a wide range of products available that settling on a combination of sonics and aesthetics one likes is not so difficult. Much like cars.

The two speakers I own a both among my favorite sounding and favorite-looking. (Perhaps that's not a coincidence )

 

[Kal Rubinson]

Measure it, silly.

The emoji should have been a signal that I was not looking for a serious response.

 

[sq225917]

There's nothing about tubes that can't be measured, but that means it can all be correlated to the human listening experience.

 

[computer-audiophile]

Well...
Still, I am a supporter of hybrid amplifiers where everything is in its place.
Long time ago two unknown to the big world Ukrainians designed the beautiful unity gain buffer based on a diamond topology (it was published in Electronics World, November 1992).
Later this buffer became the main output solution in some extremely good Audio Research amplifiers.
Until now, many adhere to this buffer (Andrea Ciuffoli for example).
And here is an oscillogramm of the same test, this is an amplifier without global feedback at all, but the amplitude for this test is more difficult:

View attachment 284917

There is no panacea, and there can be no perfection either, but a tube voltage amplifier with such a buffer works perfectly without any global feedback and without artifacts associated with it.
And the best part is that such buffers once assembled (they are very simple) last a very long time.
I assembled them a long time ago.
The amp with them isn't cheap of course, but not because of the active components or tubes, how it always works out.
But you can change tube voltage amplifiers and each time get something new and still very good.
I still like it this way.
(It's just a pity that a truly beautiful case for such a thing is extremely difficult to make in amateur conditions)

Very interesting, but with my critical remark, I refer to the Mastersound 845 SET main amp in the review and not to a preamp.

It is not a great problem to transmit a clean 1kHz rectangle with such an amp, without ringing, rounded edges, crooked top and such, if it is well done. But it is obviously not.
I always say: it must look like a perfect drawing of a rectangle - at least I have this claim to my own tube amplifiers.

 

[tmtomh]

(Interesting that my accuracy-focused brother in law preferred the more tubey-setting for some tracks).

To me the key distinction here is not what a listener - including an "accuracy-focused" listener - might prefer. The distinction is between colorations that you can select and turn on or off as in this case, versus permanent, hard-wired colorations that are said to universally improve the "realism," fidelity, or "musicality" of everything one plays on it.

So I don't actually think it's interesting that your accuracy-focused BIL preferred the tubey setting for some tracks. Had he preferred it for every track, that would in my view be interesting.

(And per comments above, this of course all assumes that the three settings do indeed produce reliably audible. measurable differences.)

 

[notsodeadlizard]

Very interesting, but with my critical remark, I refer to the Mastersound 845 SET main amp in the review and not to a preamp.

It is not a great problem to transmit a clean 1kHz rectangle with such an amp, without ringing, rounded edges, crooked top and such, if it is well done. But it is obviously not.
I always say: it must look like a perfect drawing of a rectangle - at least I have this claim to my own tube amplifiers.

It was for the 100W power buffer based amp, the output on pure resistive load.
I'm sorry for little inaccuracy.

 

[computer-audiophile]

I'm sorry for little inaccuracy.

No Problem!
I just wanted to stay in the same amplifier class like the Mastersound 845 SET for comparison.

 

[Zensō]

Ok, understood. I am very aware there are audiophiles who generally don't care how equipment looks (and to my eyes, the visuals of their set-ups tend to advertise this).

If by "prioritizing looks" you mean buying only on looks or looks well above all else - as in "who cares much how this sounds, I like the looks" - I don't think many audiophiles fall in to that category.

But if you mean prioritizing looks - taking aesthetics in to account along with the sonics - is a fool's errand, there is such a wide range of products available that settling on a combination of sonics and aesthetics one likes is not so difficult. Much like cars.

The two speakers I own a both among my favorite sounding and favorite-looking. (Perhaps that's not a coincidence )

I would argue that there is a fairly significant percentage of audiophiles who base their purchases on all kinds of things other than performance, looks being one of them.

In my case, I have a pair of Genelecs on my music production desk. I actually don’t like how they look at all, but they’re precision tools that serve their purpose perfectly, so I’m very happy with them regardless. To me, more important than how they look is how they‘re engineered and constructed, and ultimately how well they do the job they’re designed to do.

There’s room for personal preference and nuance in this, of course…

 

[computer-audiophile]

Perhaps those who believe that a good tube amplifier would 'significantly' colour the sound should first be asked to what extent they themselves have in-depth personal experience with such devices and suitable speakers. Whether they themselves have owned some, how many there were, which ones, etc.
I have rather the impression there exist about it partly adventurous ideas.

 

[computer-audiophile]

In my case, I have a pair of Genelecs on my music production desk. I actually don’t like how they look at all, but they’re precision tools that serve their purpose perfectly, so I’m very happy with them regardless. To me, more important than how they look is how they‘re engineered and constructed, and ultimately how well they do the job they’re designed to do.

Different audio things have different sound characteristics, which is why I usually have several systems or listening places at the same time. I especially like good studio monitors as well. I know Genelecs from the studio or sound art context and find them good as pro tools, privately I preferred Neumann, also because they seem to me to have a better price-performance ratio. But I also use self-designed tube amps, horn speakers, etc. They all have their weaknesses and strengths.

 

[RayDunzl]

You can't measure if a tube is good or bad.

All those machines that used to be in the Drugstores (how did they get into the tube business, anyway?) are long gone.

Not that I ever figured out how to use one, but, well, I was only 8 and was impressed by the Science Fiction Theater looks of the thing.

 

[computer-audiophile]

You can't measure if a tube is good or bad.

All those machines that used to be in the Drugstores (how did they get into the tube business, anyway?) are long gone.

Not that I ever figured out how to use one, but, well, I was only 8 and was impressed by the Science Fiction Theater looks of the thing.

View attachment 284941

There are clearly better, for example the modern computerized curve tracers. I show a picture of a 'Funke Röhrenprüfgerät' that I once used to check the tubes of my LEAK tuner. At the moment I don't have any more great measuring devices, but I don't need any.