SUT - electrical theory and practical experience

@holmz ​​​​​​

the CBS STR-112 has a 1kHz square wave for the test you propose but be warned the results of this test from a cartridge is not for the feint of heart. And yes as you suspect due to the riaa filter the actual cut of the track appears as a triangle wave.

dave

holmz ​​​​​​

the CBS STR-112 has a 1kHz square wave for the test you propose but be warned the results of this test from a cartridge is not for the feint of heart. And yes as you suspect due to the riaa filter the actual cut of the track appears as a triangle wave.

dave

Thanks Dave - I ordered one.

It might not be a triangle shape from the RIAA. But it will be good to try it.

Dear @holmz : Could be interesting to make some tests looking for the transient response rise time of a cartridge in an active high gain phono stage and other using SUT.

Exist a very old measurements made it by an electret vintage cartridge designer where he found out that the rise time of his designs was 2 micro seconds at 1khz generated square wave ( Osciloscope. ), moving magnet 25 micro seconds and a moving coil through a SUT 30 micro seconds.

That rise time is critical in transientes response by obvious reasons and you like to make measurements maybe you can do it. Just curious.

R.

Yes @rauliruegas 😎

Dear @holmz  : Things are that's really weird that the rise time in a MM cartridge been faster than in a MC cartridge because it must be the other way around and maybe was the SUT who could had the culprit, at least everything point at the sut.

R.

Dear @holmz  : Things are that's really weird that the rise time in a MM cartridge been faster than in a MC cartridge because it must be the other way around and maybe was the SUT who could had the culprit, at least everything point at the sut.

 

R

If you had an ishikawa chart of causal mechanisms, then it is possible that the inductance of a SUT could be on the list of things that limit the bandwidth.
Whether 500kHz or whatever the rise time corresponds to… is better or not, is uncertain.

Dear @holmz : Maybe you are rigth but today I know that the best SUT goes from 2hz-300khz almost flat and you have to think that are electronics that have not even that bandwindth.

My point about rise time is something different because transiente response live MUSIC is what " makes " MUSIC that at the end is a concecutive transient response notes.

By its design construction the fastest magnet cartridge is the LOMC against MM/MI/IM designs however the transiente response rise time at 1khz was measured and MM cartridge is fastest that a LOMC/sut combination and as I said the SUT made " slower " when thing must be the other way around.

With out facts my common sense tells me that a LOMC through an active bipolar hifgh gain design is way fast than the same LOMC cartridge + the additional IC cables and the SUT it self where both signal must pass through. So transient response that defines the notes/harmonics is slower through a SUT and this sole characteristic is an additonal and crucial disadvantage for a SUT.

All we know that, for example, the Etna SL quality level performance is better than the Etna that has higher output level, that’s higher inductance/impedance. Transient response rise time in the SL is faster.

R.

I forgot that rise time is from steady to the time to achieve 10% to 90% of the step response.

With out facts my common sense tells me that a LOMC through an active bipolar hifgh gain design is way fast than the same LOMC cartridge + the additional IC cables and the SUT it self where both signal must pass through. So transient response that defines the notes/harmonics is slower through a SUT and this sole characteristic is an additonal and crucial disadvantage for a SUT.

I am not a bat, nor hear like one.
I suppose that we can argue whether it is 20kHz, or higher bandwidth.

If the SUT was limiting the RF bandwidth, then it would also take care of the ringing at the high RF frequency that people talk about loading a SUT to stop.

How fast of a rise time do we need?

I would guess that the lower winding ratios would also have a higher bandwidth, or is that inductance also dependent upon the transformer core ?

I forgot that rise time is from steady to the time to achieve 10% to 90% of the step response.

If it is 50% duty cycle then it is “on”, in the half period, at the equivalent of a 2kHz rate.

10% of that would be 20kHz…
 

Dear @holmz  : This is what the gentlemans that made it the rise time measurements said and through the internet looking for bipolar, FET or tube rise time measurements coicide exactly with:

" Response speed is general refered as transiente time and transient time is the figure of merit in comparison the ability of the cartridge to reproduce the instantaneous changes of MUSIC. Transiente rise time is determined using a square wave test signal  ( 1khz. ). The transient rise time is the time elapsed from the point of the leading edge wen it's at 10% of maximum height to the point of the leading edge is at 90% of the maximum height. . This is the accepted engeneering measurement method which uses the most uniform segment of the leading edge to measure the transient rise time.Musical sounds are transients by nature. "

Differences between the MM/MC other the kind of motor design was that the LOMC cartridge was paired with an additional SUT and this is by common sense why the MM is faster in that transient rise time when obviously must be the other way around. SUT/cables is the culprit. Maybe not?

R.

tHOSE GENTLEMANS SAID:

" These measurements of cartridge circuit are of great significance to the user and illustrate why the cartridge's electrical output network has such a profound effect on the overall performance of the playback . "

r.

Differences between the MM/MC other the kind of motor design was that the LOMC cartridge was paired with an additional SUT and this is by common sense why the MM is faster in that transient rise time when obviously must be the other way around. SUT/cables is the culprit. Maybe not?

It is a system that most people have.
So looking these things in isolation is best, but it may be difficult.

We are pretty much looking at the transient response like slew rate.
At some point the thing is trying to make sounds >20kHz if the response time is going to zero.

In any case I ordered the test LP.
And I have an ADC, so I can capture the results digitally.
I’d rather not guess at what is happening.

If a SUT studied as a unit can exhibit a frequency response out to 300KHz, how can it be the principle culprit in determining a relatively slow rise time? Most cartridges do not respond out to 300KHz so far as I know.

Dear @lewm  : You tell me, don't only gave an " ask " but what do you think or your explanation about because the facts are that a MM cartridge vs a LOMC+SUT has faster transient rise time, at least was what measured tells about.

My take is that a LOMC cartridge say 0.22 mv amplified by an active high gain phono stage is faster than a MM. I never did a comparison measurements in that scenario.

Noe it's not only the added SUT but IC cable and connectors too and all these could be the culprit to slower transient response.

If you have a way diffrent " idea " then share with us.

R.

Raul, I’m thinking out loud. Just like you. You and others mentioned that a SUT is capable of an extraordinary bandwidth, out to 300K or even 500KHz. Since bandwidth is necessarily related to rise time, I’m wondering whether it’s justified to infer that a SUT is responsible for the surprising finding that an MM is faster than SUT plus MC. We’d need more data to intelligently debate the question.

Dear @chrisoshea ; That gentleman that pass away was a tube lover and this and no other is the reason of his " fondness for SUT ", the SUT down there is a mustto have a necessity a " bad " necessity.

@lewm stop to wondering and solve it, in the mid time common sense is just common sense an a good response at least for me. Not for you? then solve it ! !

Btw, 300khz is an exceptional case, normally good SUTs goes to 60khz-100khz like LOMC cartridges and MM too.

R.

Wish I knew what you were talking about, Raul.  Solve what?  It was you who posted the information that your vintage SUTs had such a wide bandwidth.  Now when it does not suit you to admit your own facts, you want to reduce the bandwidth so you can claim sans data that the SUT must be what limits the rise time of the MC cartridge in the scenario.  Truth is, that was a badly done experiment, just because it introduces the SUT as another variable that may or may not limit rise time.  It's really not worth further discussion.  If you think MC cartridges sound "faster" to you than MM types, so be it.  There is nothing here to deprive you of your subjective impression.

@lewm : What words of this posted statement you just did not understand? :

" 300khz is an exceptional case, normally good SUTs goes to 60khz-100khz "

Now: " It was you who posted the information that your vintage SUTs had such a wide bandwidth "

Wrong, that bandwindth is the exceptional Technics SUT.

Solve what?: your wondering.

Btw, those measures were SUT and added IC cables.

and it’s not for me only that the LOMC cartridges are faster than MM ones: IT’S OBVIOUS. Not for you ok, follow wondering is fine for me.

R.

First of all, when did I say I disagree with you regarding the relative "speed" of the two types of cartridge?  Second, YOU posted the bandwidth of the Technics SUT when you were trying to claim superiority for vintage SUTs over some modern ones.  Yes, it's an actual number, I agree.  You're stuck with it if you want now to argue that the SUT used in the rise time experiment is reducing the apparent rise time of the MC used in conjunction with the SUT.  But like I said (twice at least), we lack data (frequencies, impedances, capacitance, inductance, etc), and whoever performed the measurements should certainly have re-measured the MC cartridge without the SUT in the circuit. 

Yes, I still wonder what you expect me to solve with virtually no data.  To achieve a bandwidth of 300,000Hz (at 0db), a SUT must have a rise time of at least .00000333 seconds.  Is that the solution you are looking for?  It's just a number that solves nothing.

Yes, solves nothing because it's not the real issue. Do you think that any MM cartridge is faster that your MC2000?, today I know that MM are near but still behind LOMC cartridge with an output level no higher than 0.4mv.

Btw, in this week I will pick-up my Denon AU 1000 that rigth now is under measurements mainly bandwindt and distortion levels. We will see.

R.

@rauliruegas 

That gentleman that pass away was a tube lover

Art made his system choices on what gave him the most musical enjoyment and had a large readership of similar minded people.  If those choices do not align with your measurement-centric view of the audio world, maybe it is time to take out the earplugs and actually listen rather than let a device prove to you how good something must sound.

dave

Dear @intactaudio : It’s not that " do not align with your measurements " because the issue is not about just measurements.

All tube phono stages needs/necessary a SUT for LOMC cartridges and the ones active high gain tube ones are around mediocrity even the effort of the designers that’s it’s not the issue too.

If you have enough/deep live MUSIC experiences seated at near field position then you know that tubes and specially in phono stage is not the best alternative but an SS one and if you think it’s rigth then not because I say it but you are way wrong no matters what and I can prove it with facts as I did it in hundreds of threads here and in other internet forums.

I know that I don’t like you but that is up to you, not my problem. I never let that attitude against " some one " let me post with that kind of attitude, normally I’m unbiased about.

I never think to use the information you share about the RIAA deviation of your unit that as I said on the subject goes around mediocrity with that 0.66 db " fligth " in the RIAA that's good for you because is your design but that's a shame for a RIAA phono stage.

R.

Holmz, where do the data that has caused so much angst come from? (Rise time for MM at 1kHz is 25 microseconds vs for MC+SUT is 30 microseconds.) what cartridges were used? What SUT? After how many hours of use? Etc, etc. Thanks if you can reference the source of the info.

It’s not that " do not align with your measurements " because the issue is not about just measurements.

All tube phono stages needs/necessary a SUT for LOMC cartridges and the ones active high gain tube ones are around mediocrity even the effort of the designers that’s it’s not the issue too.

If you have enough/deep live MUSIC experiences seated at near field position then you know that tubes and specially in phono stage is not the best alternative but an SS one and if you think it’s rigth then not because I say it but you are way wrong no matters what and I can prove it with facts as I did it in hundreds of threads here and in other internet forums.

 

I know that I don’t like you but that is up to you, not my problem. I never let that attitude against " some one " let me post with that kind of attitude, normally I’m unbiased about.

 

I never think to use the information you share about the RIAA deviation of your unit that as I said on the subject goes around mediocrity with that 0.66 db " fligth " in the RIAA that's good for you because is your design but that's a shame for a RIAA phono stage.

This entire post is rubbish and false, including the ad hominem attacks. 

Dear @lewm  : You have a misunderstood because was not holmz who has the source, was me who asked him to make measurements taking advantage that he bougth the CBS STR 112 test LP and he said: yes but you need to read carefully all the posts about to at least have the correct info before make a post.

You need to re-read where I posted about where the electret cartridge manufacturer did not gives all what you are asking for and with unknow IC cables SUT.

Was a serious manufacturer and seems to me trusty one but you ask information as if you were the customer that " paid " to the manufacturer to make the test under your " specs " and this just did not happened.

R.

Dear @atmasphere : I think that with out an explanation your statement is a real attack directly to me:

" This entire post is rubbish and false, including the ad hominem attacks. "

Why " rubbish " ? why " false " ? and why personal " attacks " and to whom those supposed " attacks " ?

R.

@rauliruegas I attacked your post and not you. There is a difference.

Your post contains false information. For example you claim to have presented ’proof’ on multiple occasions. At best you presented ’evidence’ which can be used to point at a proof but even so your evidence is sketchy.

Your comment about tubes is not reflected by people that spend plenty of time listening to real music in real music venues. It was an entirely made up story based on your own personal anecdote as best I can make out.

Your use of the word ’mediocrity’ has some kind of personal meaning attached to it. I can use the word in a similar fashion; for example I don’t care at all a phono stage is super quiet if the sound coming from it is irritating- it is mediocre regardless. Generalizations frequently result in false statements.

This comment is an attack on the integrity of another member and is thus ad hominem:

I never think to use the information you share about the RIAA deviation of your unit that as I said on the subject goes around mediocrity with that 0.66 db " fligth " in the RIAA that’s good for you because is your design but that’s a shame for a RIAA phono stage.

Being ad hominem it is a logical fallacy so false by definition.

Raul, I see now that it was you who posted the rise time data, which are based on your memory of something published by an electret cartridge maker who, from your memory, is said to have stated that his cartridge has a rise time of 2 microseconds, compared to 25 microseconds for an MM and 30 microseconds for an MC plus SUT.  Holmz may have the test LP and a 'scope, but so far I don't see where he posted data.  SOOOOO, why don't you post a reference to the source of the above data?  If you can find it.  Sure, there can be many reasons why the data are not a reflection of the rise time of an MC cartridge taken by itself, and I am also sure that every MC cartridge is different in that regard.  Finally, if we are only going on the basis of subjective impressions, I would say that as a whole (meaning all MI cartridges I have heard compared to all LOMC cartridges I have heard), MI cartridges sound "fastest", to me. I have no idea if actual measurements would substantiate my opinion.

I don't know any individual that is a Tube Lover.

I do know individuals who have come to the conclusion that a HiFi System with devices built with Tube Circuits have found a device that is deeply satisfying and is a preferred experience over other experiences.

This can be discovered through the use of an individual device such as a  Phonostage, DAC,  Pre-Amp', Power Amp'. It is also available through a combination of Valve devices used. In many cases the combination is produced as Hybrid, being SS and Valve Devices to produce the System.

Those who take seriously finding a presentation from a system, to be one that is totally satisfying and able to deliver to their unique preferences are willing to take steps to increase experiences of differing permutations of available equipment.

Very few do any Math whilst on this journey, they are use their senses and stimulation created to settle the outcome of a assessment.

I am fortunate to have still have an interest in Live Music and on many occasions, can be at a close proximity to a performance, never ever have I used this type of  encounter to make a decision on a Tube vs SS Circuitry as being the superior, even if a see a Valve Amp in use, along with SS Instrumental Equipment. Never ever have I heard this as requirement to make such a assessment.

I was out of this thread, but such a huge BS Statement is not of any value in this thread. 

If one wants to talk about a Bass Notes Impact at a Live Performance being quite different from a Bass Note Impact produced by a Home System, then there is plenty to 'chew the cud' about.

Dear @lewm  : That manufacturer said that a LOMC ( with out SUT ) has a rise time between 15 to 21 microseconds and MM between 23-31 msg. ( all those depending of total capacitance electrical network. )

But his measured the MC through a SUT was 30 micro seconds.

Note those differences in between the LOMC and the LOMC+SUT+IC cables.

and subjectivity always told me that MC are faster but JC posted in that way in the long MM thread and faster than MI too.

I think that Holmz today measures could have certainty and under the control you ask for because we will know with wich cartridges in use and which SS active high gain phono stage and the SUT used.

R.

"That manufacturer said that a LOMC ( with out SUT ) has a rise time between 15 to 21 microseconds and MM between 23-31 msg."

To the best of my knowledge you never previously mentioned the data for an LOMC without SUT. Anyway, I doubt any of us can hear the difference between 21 usec (high value for MC alone) and 23 usec (low value for MM).  And still one would like to know how the measurements were made, but your new information does suggest that the SUT slowed down the LOMC, without allowing for explanations based on load, reactive components, etc., because we lack the information.

Dear @tmasphere :In any case what's false  is what you posted because I gave several evidences/facts/measures and in the 99% of those threads you was there and you never never proved with measurements that I was wrong, never ever.

My comments about tubes was in specific for tube+SUT or all tube phono stage designs and if you can prove that tubes in that specific area are better then design an all tube phono stage and send to STereophile for JA can makes the review. Your bla bla as almost alwyas are only bla bla and never can prove what you posted in this specific area.

" Mediocrity " means " average " and in audio the 80% of audio items according with a " normal curve " are inside that average/mediocrity level. Over that average  10% are the true high-end and at the other side of the curve are the 0ther 10% that are the really bad designs.

My comments on the RIAA deviation audio item is not an attack but a measured figure.

R.

Dear @lewm  : "  I doubt any of us can hear the difference between 21 usec (high value for MC alone) and 23 usec (low value for MM. "

I always said the main characteristic of live MUSIC that can't be achieved by any room/system is: transient response, its speed. At the same time I posted several times that transient response in a room/system is mainly what makes the differences between different room/systems and between cartridges.

I posted what the electret cartridge manufacturer said on that critical subject:

" Response speed is general refered as transiente time and transient time is the figure of merit in comparison the ability of the cartridge to reproduce the instantaneous changes of MUSIC. ..........................................Musical sounds are transients by nature. ............................................These measurements of cartridge circuit are of great significance to the user and illustrate why the cartridge's electrical output network has such a profound effect on the overall performance of the playback . "

In your statement I think that some audiophiles can discern between those 3 micro seconds difference and that could says why gentlemans with a very high quality and resolution level systems are in favor of LOMC vs MM/MI cartridges.

In my today quality and resolution level room/system I'm aware of that kind of differences between a LOMC and a MM cartridges. Even through my fine tunning time over the last 2-3 years ( maybe a little more. ) the quality performance levels between MC and MM more and more were nearer and nearer in between and today if with your blind eyes you listen in my system a MM cartridge you can´t know if it's a MM or LOMC one. Differences as so tiny that you really need to know for sure what to look for to distinguish in between. Yes, color is a little different, to little.

I can say today that in any good room/system as nearer the quality performance level is between MM and MC as better your system overall quality performance levels.

The critical importance of transiente response/speed/rise time is obvious in the Lyra example I posted where reviewers and the majority of cartridge owners prefer by a tiny margin the Etna/Atlas SL versions vs its higher output models. I experienced that with the Kleos and Kleos SL.. Yes, the SL are a little faster with better transient response and this is what makes the difference because both cartridges have the same design and tested in the same room/system.

I know there are no measurements behind that ( or maybe are and I just don't know. ) but all those evidence are or could be in some ways facts to take in count when we are talking of the transient response importance in the whole quality performance of any room/system.

Maybe you have a way different opinion, that's mine.

R.

Not proclaiming to be any expert, but when discussing 'rise time' the traditional engineering parameter s 'slew-rate' dvt/dt = X-volts/micro-sec.  And once you are talking about slew-rate there is some pretty established science associated with it such as that described in the following recognizing that the 'amplifier" gain (be it SUT+tubes or solid state) has an effect and that to produce a specific frequency there is a minimum 'slew rate'.

Slew Rate: What is it? (Formula, Units & How To Measure It) | Electrical4U

AN-346 High-Performance Audio Applications of The LM833 (Rev. D)

Phono Preamp Project - Graham Slee Audio Forum | HiFi System Components - Page 2

And in the Texas Instruments document there is this paragraph:  

"In addition to the amplitude response errors (which can be made small through careful design), the lack of a continued rolloff can cause distortion in later stages of the audio system by allowing high frequency signals from the pickup cartridge to pass through the phono equalizer without sufficient attenuation. This is generally not a problem with moving magnet cartridges, since they are usually severely band-limited above 20 kHz due to the electrical resonance of cartridge inductance and preamp input capacitance. Moving coil cartridges, however, have very low inductance, and can produce significant output at frequencies as high as 150 kHz. If a subsequent preamplifier stage or power amplifier suffers from distortion caused by slew-rate limitations, these ultrasonic signals can cause distortion of the audio signal even though the signals actually causing the distortion are inaudible."

Dear @antinn  : Those LM op-amps came from now defunct National but the best bi-polar discrete dual is the MAT 02/03 that today were substitute by similar part by Analog Devices, that's not an op-amp. I know very well because Levinson used at its amplifier reference input boards.

Now, that theory/science in your links forgot that MM cartridges are not " severely limited " in frequency, we have several MM cartridges with flat response out of 100khz as Technics, Empire, Audio Technica, Signet, ADC, Azden and many others to mention here.

It's true that the S could distort ( inaudible. ) the cartridge signal if the designer does not takes in count that " science "

The phonolinepreamp in my system has a bandwindth over 1.5Mhz with 350 V/mseg but was designed with out any of those " troubles ".

Anyway, thank's for the links, very informative. We are waiting for the Holmz measures about.

R.

In any case what's false  is what you posted because I gave several evidences/facts/measures and in the 99% of those threads you was there and you never never proved with measurements that I was wrong, never ever.

bla bla bla... I see now that you have moved from giving 'proof' to providing 'evidence'. Gotta keep your story straight...

@atmasphere 

I find it quite incredible how many people on A‘gon indulge in absolutist and arrogant language without any knowledge basis for their argument. Don‘t be discouraged by them, your contributions are always well founded and instructive. Thanks for that.

Anyway, thank's for the links, very informative. We are waiting for the Holmz measures about

@rauliruegas Things are moving slowly, and i am not providing evidence.
I am just trying to get the loading right by using a graph,
 

@holmz  : No problem, my mistake.

R.

Dear @antigrunge2  : " arrogant language without any knowledge basis for their argument. "

Please give us an examples of " arrogant language " from "  incredible how many people on A‘gon.

and if you can share with us from where or why you said " without any knowledge basis for their argument. "  Some examples could be fine.

Appreciated.

R.

holmz  : No problem, my mistake.

 

R

@rauliruegas 

When I left the TT a few weeks back, it was looking like this:

 

So it is on the table of the operating theatre and a new bearing is en route.

I was not able to find an anodiser to anodise the arm board, so I’ll put in, in the shiny raw alloy state.

@rauliruegas,

For the record and no pun intended, TI did not exclude wide bandwidth MM.  Their written statement was "This is generally not a problem with moving magnet cartridges, since they are usually severely band-limited above 20 kHz...".

Otherwise, your preamp spec with slew-rate 350 V/us and 1.5MHz bandwidth mathematically (using the equation to determine slew rate at frequency) is capable of a peak voltage (at 1.5MHz) of about 3.7V.  Any more than this and at 1.5MHz, the amp becomes unstable.

What does this mean in real-life?  Well, that's a good question.  There are obvious 'designers" such as Goldmund and Spectral WELCOME to Spectral Audio'sHome Page who adhere to very high 'speed' high slew-rate (Spectral is >1000 V/us with bandwidth 1.5 MHz) designs as the optimum.  While others do not.  

The 'bandwidth' (no pun intended) of audio design and followers of each is equally wide (no pun intended).  For one to stipulate that one is better than the other, IMHO is an exercise in futility given the wide variation in just individual sensitivity to sound which academia has indicated can be a factor of 10:1:  

Consider what is written page 16 – of Microsoft Word - P406POM_Lect5.doc (illinois.edu) UIUC Physics 406 Acoustical Physics of Music ©Professor Steven Errede, Department of Physics, University of Illinois at Urbana-Champaign, Illinois 2002 - 2017. The Human Ear ⎯ Hearing, Sound Intensity and Loudness Levels (78) "The time-averaged, or RMS sound intensity threshold of hearing (@ f = 1 KHz) is: ~ 2.5x10-12 RMS Watts/m2 = 2.5 RMS pico-Watts/m2. Individual people may hear better/worse than the average person, and so threshold of hearing from one person to another can vary as much as 1/10 or 10X this!!!".

Take care and best wishes for the holidays,

antinn, In your quoted paragraph, I think they are using "Watts" as an expression of acoustic power or energy.  On that assumption, and wanting to know how acoustic watts is defined, I found this on Wiki: "Sound power or acoustic power is the rate at which sound energy is emitted, reflected, transmitted or received, per unit time.^[1] It is defined^[2] as "through a surface, the product of the sound pressure, and the component of the particle velocity, at a point on the surface in the direction normal to the surface, integrated over that surface." The SI unit of sound power is the watt (W).^[1] It relates to the power of the sound force on a surface enclosing a sound source, in air. For a sound source, unlike sound pressure, sound power is neither room-dependent nor distance-dependent. Sound pressure is a property of the field at a point in space, while sound power is a property of a sound source, equal to the total power emitted by that source in all directions."  It's not an easy concept to grasp.

It is now within this thread, having evolved from a useful supply of information, that most visitors would like to take something from, to a very unusual concern, where a minuscule quantity of individuals concern themselves.

The presenting of a Math as the reasoning to impose the notion that another method is lesser and not the optimised circuit is really starting to taint a well presented thread, as result of its former contributions.

The thread now is grounded with ones intention to attempt to impress their Mathematical Preference as being the better over another.

This attempt to hold centre stage, is being met by others, with a countering of this  very obvious intention at large, especially where the Math has been used as the support for the notion being proposed.

The Mass of Users of Devices as a Listener, do not care for such a Topic of Discussion.

As said many times, the Judgement made on a device is commonly born from there being an attraction toward it, either through Clever Marketing, Word of Mouth, Aesthetic appeal, Cost, Discounted Cost, Gifted, Impact Made During a Demonstration, Stimulus Created, Attractive Experience Worthwhile to Maintain.

Somewhere behind all the above that coming together in one permutation or another is Math. It is quite difficult to see where the individual place much care on the Math that is not the commonly used criteria for matching a Device to another Device.

The Topic of Math most recently under discussion and now dominating as a Spoiler, is as far to the extremities and circumscribed in content, as can be imagined, when comparing the content to the OP's original request for information. 

…
 

Somewhere behind all the above that coming together in one permutation or another is Math. It is quite difficult to see where the individual place much care on the Math that is not the commonly used criteria for matching a Device to another Device.

The Topic of Math most recently under discussion and now dominating as a Spoiler, is as far to the extremities and circumscribed in content, as can be imagined, when comparing the content to the OP's original request for information.

Respectfully I’ll offer an alternative…

The section with the URL link on “the gain of SUTs” had some compelling maths that to help to show how some SUTs may be a better match for some carts.

I would say that that “linked info” falls squarely within the second paragraph of the OP’s ( @drbond  ) question.

Para2:

…
Assuming an appropriately / ideally matched SUT and MC, What are the inherent advantages or disadvantages of inserting a SUT after the MC in the audio chain?  Does the SUT theoretically enhance or degrade the sound quality?  What does the SUT actually do to the sound quality? 

Even the OP’s first paragraph mentioned wanting to understand the theory behind a SUT. So the beauty of Maxwell’s equations sort of is a real manifestation of scientific understanding becoming an engineered product.

While many an end user may not want to understand it, and would rather have a recommendation of one particular SUT and similarly one specific cart… it is none the less a true thing of beauty how both the cart and SUT work.
There is more science and math in it than magic .

But the OP can (and should) certainly drive the conversation in a way that helps them.

+1 @fuzztone …..it’s about gain, simple.  

@rauliruegas

just read your own posts, preferably before posting!

@lewm,

Not to take too much of a tangent from the intent of this thread, but this article should clarify sound intensities in watts per meter squared with the more commonly used sound intensity levels in decibels (dB) - Sound Intensity and Sound Level | Physics (lumenlearning.com).

Take care and best wishes for the holidays,

I do agree, it is for the OP to steer a thread, if the content of it is developing into a discussion beyond their needs and seen to be best kept as a separate topic.

The Topic makes a lot of sense when maintained in a area where the Science in use has a Audible to the Human Ear function.

It looks like Bats are being catered for in the frequencies being presented and being a outcome of a Theorem presented.

This Thread is now about Theorem and whether one version is able to be proven superior to another, even thought the condition under discussion may not even be audible to the Human Ear, and certainly most unlikely to be audible to the individuals Spoiling the Thread with the attempts to maintain the Math as the important area of discussion.   

If I was a visitor to this thread, my first thoughts would be to question the understanding of the Theorem being presented by those who are enforcing the subject to the forefront.

I don't trust many views presented on Math, as there are those that can read it and comment on it, as their interpretation, and there are those that produce the Math. The producers of Math that has become Theorem, are quite a different being to a interpreter of a produced Math.   

Some of us find the science of these devices to be interesting per se.  Some others do not.  Based on his posts to start the thread and subsequently, I judge that the OP is one of those interested in the science. If he thinks the thread has drifted away from his intended question (which it has once or twice), he can say so here. If you prefer the subjective experience of "listening" as the sole means of selecting the elements of your audio system, I respect that.  I prefer a mixture of both, but anyone who is turned off by the technical language can simply stop reading.  Argumentative sidebars about whether SUTs are good or evil are beside the point of the thread; I agree. I do not nor have I ever owned a SUT nor heard one in my system, yet I do find the subject interesting, and I am open-minded as to the potential virtues, because of the testimony of so many others who do use SUTs.

Pindac, What "theorem" are you referring to?  Thanks.