What an OTL is, and why you should care

DonH50

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Most tube amps exhibit relatively high second-order distortion (and other even order products) that may sound "richer" or "fuller" compared to SS amps that have lower overall distortion. A minor quibble with Ralph: in addition to distortion, output impedance is IME a big factor in the difference between SS and tube amplifiers. The high output impedance of most tube amplifiers means they are more sensitive to the load and thus tend to exhibit greater differences in frequency response than SS amps (very general statements, quite sure to be untrue for specific amps of either flavor). Again IME amp/speaker matching is more critical with tube amps than SS amps (again, a line of exceptions is sure to form).

One thing I have long suspected is that intermodulation distortion is part of the reason folk prefer tubes. SS usually has lower distortion, but it tends to be odd-order by design, whereas tube circuit tend toward single-ended designs that are dominated by even order harmonics. Even-order intermodulation distortion (IMD), created when two or more signals are present, falls at frequencies far removed from the two original tones (roughly DC and twice their frequency assuming the two tones are closely spaced). In contrast, odd-order IMD appears very near the original tones, at frequencies related to the difference between the tones, so adds non-harmonic distortion close to the original tones. Close enough, and it is masked as Ralph said, but often enough is not close enough and creates a dissonance to the sound. Feedback solves that problem, but again as Ralph said it takes careful design to make that work.

@Gregadd : Not trolling at all! But my answer isn't likely to help, still wishy-washy... Richer/fuller compared to SS is what I think I meant (been a while since that exchange). Having played with bands and in an orchestra for many years, I feel it is almost impossible to know how closely a recording matches the original. A tympani can be tuned loosely or tight, a piano is usually "stretched" in tuning and how the string groups are tuned varies with the tuner and desires of the artist, different reeds sound different, brass players can create a huge range of sounds depending upon their desires (plus instrument, mouthpiece, mutes, etc.), and so forth. Then there is the impact of the venue (room), mic technique, etc. So I tend to listen for what I like rather than thinking how how true to the source it is, unless it is grossly "off".

The low damping factor (high output impedance) of many tube amps tends to allow the bass drivers to "ring" a little and that causes a little "bloom" to the sound, a little boost in the mid and lower bass. It actually sounds good to most folk, myself included, but is not accurate to the recording. Again in my experience, and what I have measured, which does not include an Atma-Sphere amplifier nor really any modern tube amplifier on a system and in a room I know. And again IME "accurate" is not always what audiophiles seek; there is room for preference. There are things I miss about my old tube amps, knowing they are not as accurate as my SS amps, but I can enjoy them all.

FWIWFM/HTH/IME/IMO/my 0.000001 cent (microcent) - Don
 

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Most tube amps exhibit relatively high second-order distortion (and other even order products) that may sound "richer" or "fuller" compared to SS amps that have lower overall distortion. A minor quibble with Ralph: in addition to distortion, output impedance is IME a big factor in the difference between SS and tube amplifiers. The high output impedance of most tube amplifiers means they are more sensitive to the load and thus tend to exhibit greater differences in frequency response than SS amps (very general statements, quite sure to be untrue for specific amps of either flavor). Again IME amp/speaker matching is more critical with tube amps than SS amps (again, a line of exceptions is sure to form).
Our amps are fully differential from input to output and so even orders are cancelled at every stage of the amp, not just the output. That is why they exhibit a cubic non-linearity rather than the quadratic as you ascribe to tube amps above. Its a matter of topology.

Output impedance is certainly an issue, which is why I've always been careful to vet speakers vs amps in any system. But if the FR isn't perfectly flat the ear may not care all that much (no speaker is flat either) as long as the distortion isn't a contributing factor- the ear has a tipping point where it will favor the tonality created by distortion over actual FR. As long as you are careful in this regard you can work around the output impedance issue. This was common practice 50-70 years ago!
 

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The answer is just above:

Sound pressure is one thing, sound quality is another! The speaker can only reproduce information supplied to it by the amplifier. If the amplifier is making more distortion on account of the load impedance, so will the speaker. That all amps do this is easy to see in their specs. You might think it 'negligible' but if the distortion is made of higher ordered harmonics it will be audible as harshness and brightness, since that it the tonality assigned to the higher orders by the human ear.

The ear is keenly sensitive to the higher orders since it uses them to sense sound pressure- and the ear has over a 120dB range! We're more sensitive to the higher orders than almost anything else. BTW it is the presence of the higher orders in low levels that is responsible for the traditional brightness and harshness of solid state amps in the last 60 years: quite literally this is why tubes are still around so long after being declared obsolete back in the 1960s.
Thanks for the response. Also, I am aware of even and odd order harmonics, however challenges in driving lower impedance as I understanding it are mostly not an issue with more modern design amps. In addition, I don't believe it's fair to simply compare static impedance values as no speaker has a flat impedance curve. Add to that variables like efficiency and phase and there's a lot more complexity than stating 16 ohms sounds better than 8 ohms because higher impedance = lower distortion.

One more data point nugget - I would argue that in the last ~10 years some of the best speakers in the world have been brought to market from companies like Wilson, Vandersteen, Vivid Audio and Magico to name a few. Not one is nominal >8 ohms yet they yield some of the best of the best sonics and - most amps I've seen coupled with these speakers are SS. So high end speaker manufacturers and high end (SS) amplifier manufacturers have no problem designing and coupling their products for the best sound on the planet. So - please help me understand why we need 16 ohms designs again?
 
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DonH50

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Our amps are fully differential from input to output and so even orders are cancelled at every stage of the amp, not just the output. That is why they exhibit a cubic non-linearity rather than the quadratic as you ascribe to tube amps above. Its a matter of topology.

Output impedance is certainly an issue, which is why I've always been careful to vet speakers vs amps in any system. But if the FR isn't perfectly flat the ear may not care all that much (no speaker is flat either) as long as the distortion isn't a contributing factor- the ear has a tipping point where it will favor the tonality created by distortion over actual FR. As long as you are careful in this regard you can work around the output impedance issue. This was common practice 50-70 years ago!
That's very cool! I had that in the back of my mind from your pervious posts but was not sure. Many years ago I designed a preamp that was fully differential. Worked and measured great, much lower distortion and hum (CM noise) than my SP3a1. A few listeners felt it was "too solid state", natch.

In terms of impedance, I was not thinking of the distortion, or even of the frequency response change being objectionable, just that it was detectable in listening tests.

But wait, no speaker is flat, the horror! :)

Thanks for the explanation, I'll try to remember next time, and should see what white papers you have on your site. Definitely the "new breed" of tube amplifiers.
 
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Gregadd

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Don, Unfortunately ,for me at least, you chose to double-down y on our previous position. As usual your argument is intellectual and polite.
I wonder if you and Ralph would consider collaborating on a book. Or at least consider compiling your previous articles on the subject. I would buy it.
 

Gregadd

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Most tube amps exhibit relatively high second-order distortion (and other even order products) that may sound "richer" or "fuller" compared to SS amps that have lower overall distortion. A minor quibble with Ralph: in addition to distortion, output impedance is IME a big factor in the difference between SS and tube amplifiers. The high output impedance of most tube amplifiers means they are more sensitive to the load and thus tend to exhibit greater differences in frequency response than SS amps (very general statements, quite sure to be untrue for specific amps of either flavor). Again IME amp/speaker matching is more critical with tube amps than SS amps (again, a line of exceptions is sure to form).

One thing I have long suspected is that intermodulation distortion is part of the reason folk prefer tubes. SS usually has lower distortion, but it tends to be odd-order by design, whereas tube circuit tend toward single-ended designs that are dominated by even order harmonics. Even-order intermodulation distortion (IMD), created when two or more signals are present, falls at frequencies far removed from the two original tones (roughly DC and twice their frequency assuming the two tones are closely spaced). In contrast, odd-order IMD appears very near the original tones, at frequencies related to the difference between the tones, so adds non-harmonic distortion close to the original tones. Close enough, and it is masked as Ralph said, but often enough is not close enough and creates a dissonance to the sound. Feedback solves that problem, but again as Ralph said it takes careful design to make that work.

@Gregadd : Not trolling at all! But my answer isn't likely to help, still wishy-washy... Richer/fuller compared to SS is what I think I meant (been a while since that exchange). Having played with bands and in an orchestra for many years, I feel it is almost impossible to know how closely a recording matches the original. A tympani can be tuned loosely or tight, a piano is usually "stretched" in tuning and how the string groups are tuned varies with the tuner and desires of the artist, different reeds sound different, brass players can create a huge range of sounds depending upon their desires (plus instrument, mouthpiece, mutes, etc.), and so forth. Then there is the impact of the venue (room), mic technique, etc. So I tend to listen for what I like rather than thinking how how true to the source it is, unless it is grossly "off".

The low damping factor (high output impedance) of many tube amps tends to allow the bass drivers to "ring" a little and that causes a little "bloom" to the sound, a little boost in the mid and lower bass. It actually sounds good to most folk, myself included, but is not accurate to the recording. Again in my experience, and what I have measured, which does not include an Atma-Sphere amplifier nor really any modern tube amplifier on a system and in a room I know. And again IME "accurate" is not always what audiophiles seek; there is room for preference. There are things I miss about my old tube amps, knowing they are not as accurate as my SS amps, but I can enjoy them all.

FWIWFM/HTH/IME/IMO/my 0.000001 cent (microcent) - Don
I guess what I am wrestling with here is what is apparent o me, the willingness of some to be OK with distortion of some type that produces an amusical sound. Provided that sound is produced by equipment that measures in a way they find acceptable. Yet they they reject a more musical sound that does not measure to their standards
No offense intended but I find this I will just choose what like unacceptable.. I am not sure this is accurate. I have followed you since the inception of this forum. I find your position difficult to defend. You describe all matter of differences in sound while listening live. But for recorded music you have no idea. Certainly we can have reasonable idea what B.B. Kings' guitar sounds like.
Perhaps I am just beating a dead horse.
 

DonH50

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I guess what I am wrestling with here is what is apparent o me, the willingness of some to be OK with distortion of some type that produces an amusical sound. Provided that sound is produced by equipment that measures in a way they find acceptable. Yet they they reject a more musical sound that does not measure to their standards
No offense intended but I find this I will just choose what like unacceptable.. I am not sure this is accurate. I have followed you since the inception of this forum. I find your position difficult to defend. You describe all matter of differences in sound while listening live. But for recorded music you have no idea. Certainly we can have reasonable idea what B.B. Kings' guitar sounds like.
Perhaps I am just beating a dead horse.
I am not sure I understand; I wish we were sitting across a table and bet we could clear it up in five minutes.

Preference is just that; listening for what one likes (prefers), whether it is true to the source or not. Adding to the confusion is the debate about whether the recording source is true to the original performance; I don't see how you can know that if you were not there. But that does not mean I don't know what a guitar, or piano, or trumpet ;) sounds like, and if a recording didn't sound "real" to me I would not likely keep or play it again. I think you may be taking my position too far and thus infer I am not presenting myself clearly. I hope I would recognize something that was "amusical" and reject that recording.

Certainly I know well enough what an orchestra (for example) should sound like, and if my system doesn't meet my expectations then I consider it broken. If the sound produced does not match what I expect to hear based upon my experience then I search for the reason. But I can't claim to know the difference between Carnegie Hall and Pikes Peak Center based on a recording; I have heard orchestras in both places, but different orchestras, different music, and long ago (at least for Carnegie) so I can't swear I could pick one venue from the other based upon a recording especially knowing nothing about how the recording was made. You can modify the tonal balance and sense of "space" in the recording process. But that is not arguing for "amusical"; I would consider that a step beyond preference. The recording and mastering engineers choose what to emphasize, how much of the venue is in the mix, what to add and take away... Hopefully the best recordings provide aural cues so I can identify the hall as well as immerse myself in the music.

I remember an interview decades ago wherein the interviewer commented on how well the reverberation and sense of space of the hall was captured in a recording. The artist laughed and said that was all added later; the initial recording was dry and included takes in a studio, with the ambience added later during mastering.

For myself, I choose components that are as accurate as possible (within my budget) in terms of their technical performance, and trust (but verify through listening and measurements) they will faithfully reproduce the recording. The best systems and recordings have me "being there".

Sorry for the off-topic comments, this does not really have anything to do with OTL (except maybe as applied to making tube amplifiers more accurate and thus truer to the source).
 

Gregadd

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Well Don I get it . But I don't get it. l understand your argument. Putting it into practice would lead me to an unacceptable result. Leaving it to personal preference to me at least ,"says feel free to be wrong."
You can't generalize from the specific. I Will not bother to do it. I can match you anecdote for anecdote. The fact someone was fooled by a recording proves nothing.
I wish I could win you over but I'll leave it here.
 

DonH50

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Well Don I get it . But I don't get it. l understand your argument. Putting it into practice would lead me to an unacceptable result. Leaving it to personal preference to me at least ,"says feel free to be wrong."
You can't generalize from the specific. I Will not bother to do it. I can match you anecdote for anecdote. The fact someone was fooled by a recording proves nothing.
I wish I could win you over but I'll leave it here.

Curious: What is your reference? How do you determine if what you are hearing is accurate? What is your goal for your own system?

Audio seems to be mostly about subjective impressions. Every time I try to debate from the objective side I get hammered, so maybe I am leaning too far the other way to allow for preference. In my own system I strive for accuracy, but in the end it's supposed to be fun, and people's idea of "good sound" seems to vary widely (or maybe "wildly").
 

Atmasphere

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One more data point nugget - I would argue that in the last ~10 years some of the best speakers in the world have been brought to market from companies like Wilson, Vandersteen, Vivid Audio and Magico to name a few. Not one is nominal >8 ohms yet they yield some of the best of the best sonics and - most amps I've seen coupled with these speakers are SS. So high end speaker manufacturers and high end (SS) amplifier manufacturers have no problem designing and coupling their products for the best sound on the planet. So - please help me understand why we need 16 ohms designs again?
''best sound on the planet' is certainly open to debate in this case! The problem you are up against in this statement is most amplification isn't up to it even if the speakers somehow are.

Actually one of the best speakers made is 16 ohms (Classic Audio Loudspeakers- all the brands you mentioned struggle to keep up with them). The impedance isn't why a speaker is good but it certainly affects how the amplifier behaves and you can see this in their specs. Since most solid state amps use insufficient feedback (and this is why they sound bright and harsh, since their distortion is rising with frequency) going to a higher impedance is a simple way to reduce harshness and increase low level detail (since distortion obscures detail).

In high end audio its all about reducing audible distortion and getting closer to the music. While it is true that most solid state amps can easily double power into 4 ohms, that isn't the same as saying those amps sound best into 4 ohms and they don't. IOW if sound quality is your goal your amplifier investment dollar will be best served by a speaker of higher impedance. If sound pressure is your goal you have a 3dB reason to go with 4 ohms over eight.

Speaker cables become far more critical using 4 ohms and less as they can substantially reduce damping factor and resolution. By contrast at 16 ohms the speaker cables really aren't that critical.

A related issue is that 4 ohms is often accompanied by poor phase angles and low efficiency. As an amp manufacturer, I can tell you that its not good to make any amplifier work hard for a living- you will be forcing it to make more distortion. It doesn't matter if you can weld with the output section of the amp if the result isn't musical! In addition, thermal or power compression is a very real thing when efficiencies are low. Note the use of the word efficiency as opposed to sensitivity- the two are not the same when dealing with 4 ohms- subtract 3dB from the sensitivity figure to get the actual efficiency. So if you have a 4 ohms speaker that is 88dB sensitivity, the problem you have is that its next to criminally inefficient; finding a 1000 watt amp to make that play properly in most rooms will be a challenge because amps of that power sound more like electronics than they do music.

While it is true that some good speakers are 4 ohms the question you're not asking is what would those same speakers sound like had they been designed to be 16 ohms? Of course the answer is 'smoother and more detailed'.

Earlier I wrote about the use of feedback in amplifiers. Based on your closing comments in the quote above I really feel like you would benefit re-reading my earlier post, paying attention to my comments about feedback. What you will see is that most solid state amps don't use enough! I'm not one of those types that eschew feedback (although our tube amps don't use it); its just that I understand the simple fact that if you can't apply enough you'll be more likely to have a musical sounding amp if you don't apply any at all. Most solid state amps don't have enough because their designers didn't recognize this fact or simply didn't care. But there are a few that do and they have made exceptional products. High end audio is always about intention- not price.
Curious: What is your reference? How do you determine if what you are hearing is accurate?

I use recordings that I recorded myself. I have them on LP and CD; in this way I can know instantly how well a stereo is doing.
 

Phantom-Audio

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Please help me explain why we should go back to 16 ohm when pretty much every amp post - Vietnam can drive 8 ohm if not 4 ohm speakers?
My Classic Audio Both The T1.5 And The T1.3 Field Coils produce real music I feel connected. (If that means anything) its why I left every other brand and stuck to these. They are special and kick ass. The s=ystem plays anything even hard house techno music drum and bass nothing ever breaks down. It keeps up with the speed of any form of music. Try that with a SET Amplifier and you feel the system starts to struggle.

I don't know what ralph talks about half the time as his technical terms just baffle me constantly when I discuss to him about my observation, Im more interested in how it all performs. that old school syrupy time sound is defiantly not closer to the music in my opinion.



Few Things I have observed about the OTL and the Classic Audio Speaker, You can play super loud but never once ever feel it's irritating you in actual fact you can go a bit too crazy on the volume if you're not careful as it never feels too loud, you constantly want to put the volume up. I have never felt the same like this with any of my previous speakers and amplifier combo.

You can also have a conversation in the room with others whilst the music is very loud I'm talking about 90-100db with out feeling the music is just too loud.

The Music Floats in the Air, This Phenomenal attribute has never been experienced with any other systems at other Dealers room or Show condition or at any other friends Setup.

The Sound is diffused and fill the rooms soon as you walk away from the sweet spot you're kinda feeling the singer is still directly singing at you. It feels a bit spooky.

Dynamics is off the charts.

My Digital Source is Playback Design Dream Series and in my opinion, its one of the most Fatigue Free DAC I have ever known, that together with the OTL and the Classic Audio Loudspeaker Produces a Transparent Sound, that will rival any Solid State but yet it keeps a Smooth refined pose regardless of volume being pushed into the room.

So Far, I am yet to find a combo that will keep up and rival this setup.


So all this actually does not answer your question about 4 or 8 or 16ohms, Ralph has his technical Explanation, All I can do is put in a Personal opinion.

I own Studio Speakers too and use them for my office and Bedroom but even studio speakers with their solid-state amp can not rival this setup in sheer musical playback.
 

Phantom-Audio

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What i don't understand is how the OTL/Field Coil System can be so Transparent but at the same time so Smooth. It never Feels Harsh unless you're playing a really crappy recording.

This level of transparency actually is on par with the most expensive Studio Speakers i still own. Whilst the Studio Speakers will sound fatiguing this never does. I always lose track of time into the early hours of the morning. This is something I do not experience with any Single Driver Speaker, Solid State Systems, Studio Systems, SET and Horn Systems etc etc.
 

Atmasphere

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What i don't understand is how the OTL/Field Coil System can be so Transparent but at the same time so Smooth. It never Feels Harsh unless you're playing a really crappy recording.

This level of transparency actually is on par with the most expensive Studio Speakers i still own. Whilst the Studio Speakers will sound fatiguing this never does. I always lose track of time into the early hours of the morning. This is something I do not experience with any Single Driver Speaker, Solid State Systems, Studio Systems, SET and Horn Systems etc etc.
Part of this is speed and part of this is what kind of distortion is being generated. The trick with distortion is to do everything you can to make sure the circuit is linear. What we've done for decades on now in our amps that is a bit unusual (other than the fact that the amps are OTLs) in that they are fully differential and balanced from input to output. This causes the even ordered harmonics to cancel at each stage of gain throughout the amp. Because this is the case distortion isn't compounded to the degree that it is in a single-ended circuit.

Because distortion isn't compounded as much, as the order of the distortion harmonic is increased, its amplitude falls off at a faster rate than in a single-ended circuit. In addition the 3rd harmonic is the primary distortion component. It is treated by the ear the same as the 2nd (IOW its innocuous and contributes to 'bloom' and 'warmth') and is present at a much lower level than the 2nd is in a single-ended circuit. Because it is significantly higher than the succeeding orders though, it masks them from the ear. So the amp sounds smooth on that account, and because the distortion is inherently lower, also more neutral.

The output section is exceedingly fast- it has linearity to well past 20MHz. We've actually experimented using versions of the circuit as linear RF amplifiers! The bandwidth is intentionally limited by the driver circuit. In a nutshell the amp is very fast in terms of risetime; that in combination with field coil drivers makes for very high speed reproduction (field coil drivers can have speeds similar to ESLs and for the same reason- the motive field does not sag when the driver is asked to do work) that is low distortion as well.

Because the amp runs zero feedback, to have low phase shift it is essential that it be wide bandwidth. So it has unmeasurable squarewave tilt at 20Hz (IOW no phase shift at 20Hz which can rob an amplifier of impact, owing to 2Hz full power response) and less than 1degree of phase shift at 20KHz as well. This is important in two ways- the ear can percieve phase shift of a group of frequencies (although it cannot if only a single frequency) because it uses phase information to help ascertain the soundstage. The other way the ear perceives phase shift is as a tonality; a rolloff close to 20KHz can cause the amp to sound dark. Filter theory tells us why; the phase shift components when dealing with this kind of rolloff can be detected to 1/10th the cutoff frequency or 10x the cutoff frequency depending on which end of the spectrum we're talking about.
 

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Brilliant post Ralph!
 

Gregadd

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Curious: What is your reference? How do you determine if what you are hearing is accurate? What is your goal for your own system?

Audio seems to be mostly about subjective impressions. Every time I try to debate from the objective side I get hammered, so maybe I am leaning too far the other way to allow for preference. In my own system I strive for accuracy, but in the end it's supposed to be fun, and people's idea of "good sound" seems to vary widely (or maybe "wildly").
Although I am reluctant to admit it I am a classic audiophile subjectivist.
Accuracy is not my thing.
My goal is to enjoy reproduced music.
We don't need to allow for preference. Most will buy what they like. It goes foul when something is purchased because someone said you must.
It was fun being banned from ASR.
I don 't think you get hammered. IMO you acquit yourself well.
 

DonH50

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Although I am reluctant to admit it I am a classic audiophile subjectivist.
Accuracy is not my thing.
My goal is to enjoy reproduced music.
We don't need to allow for preference. Most will buy what they like. It goes foul when something is purchased because someone said you must.
It was fun being banned from ASR.
I don 't think you get hammered. IMO you acquit yourself well.
Thanks Greg.

When preference and I get sideways is when preference is presented as more accurate or as an absolute when it clearly is not. But that can also be true of measurements; since test equipment can resolve better than we can hear, then choosing an amp with 0.001% THD over one with 0.01% at rated power, assuming rated power is the same, is arguably an exercise in "subjective preference".

I tend to treat my stereo like my trumpet. In the selection process, or the practice room, I want to be very analytical and work toward perfection. When listening or performing it's all about the music and I try to turn the analytical side off and just focus on good sound (produced or reproduced). Or at least what sounds good to me (and hopefully the audience).
 

Gregadd

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Thanks Greg.

When preference and I get sideways is when preference is presented as more accurate or as an absolute when it clearly is not. But that can also be true of measurements; since test equipment can resolve better than we can hear, then choosing an amp with 0.001% THD over one with 0.01% at rated power, assuming rated power is the same, is arguably an exercise in "subjective preference".

I tend to treat my stereo like my trumpet. In the sthatelection process, or the practice room, I want to be very analytical and work toward perfection. When listening or performing it's all about the music and I try to turn the analytical side off and just focus on good sound (produced or reproduced). Or at least what sounds good to me (and hopefully the audience).
-subjective preference- that is illusory.
 

Gregadd

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-subjective preference- that is illusory.
Don Classic makes an annual appearance AT CAF. Driven by atma sphere it might your mind about tube amp colorations.
 

sbo6

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''best sound on the planet' is certainly open to debate in this case! The problem you are up against in this statement is most amplification isn't up to it even if the speakers somehow are.

Actually one of the best speakers made is 16 ohms (Classic Audio Loudspeakers- all the brands you mentioned struggle to keep up with them). The impedance isn't why a speaker is good but it certainly affects how the amplifier behaves and you can see this in their specs. Since most solid state amps use insufficient feedback (and this is why they sound bright and harsh, since their distortion is rising with frequency) going to a higher impedance is a simple way to reduce harshness and increase low level detail (since distortion obscures detail).

In high end audio its all about reducing audible distortion and getting closer to the music. While it is true that most solid state amps can easily double power into 4 ohms, that isn't the same as saying those amps sound best into 4 ohms and they don't. IOW if sound quality is your goal your amplifier investment dollar will be best served by a speaker of higher impedance. If sound pressure is your goal you have a 3dB reason to go with 4 ohms over eight.

Speaker cables become far more critical using 4 ohms and less as they can substantially reduce damping factor and resolution. By contrast at 16 ohms the speaker cables really aren't that critical.

A related issue is that 4 ohms is often accompanied by poor phase angles and low efficiency. As an amp manufacturer, I can tell you that its not good to make any amplifier work hard for a living- you will be forcing it to make more distortion. It doesn't matter if you can weld with the output section of the amp if the result isn't musical! In addition, thermal or power compression is a very real thing when efficiencies are low. Note the use of the word efficiency as opposed to sensitivity- the two are not the same when dealing with 4 ohms- subtract 3dB from the sensitivity figure to get the actual efficiency. So if you have a 4 ohms speaker that is 88dB sensitivity, the problem you have is that its next to criminally inefficient; finding a 1000 watt amp to make that play properly in most rooms will be a challenge because amps of that power sound more like electronics than they do music.

While it is true that some good speakers are 4 ohms the question you're not asking is what would those same speakers sound like had they been designed to be 16 ohms? Of course the answer is 'smoother and more detailed'.

Earlier I wrote about the use of feedback in amplifiers. Based on your closing comments in the quote above I really feel like you would benefit re-reading my earlier post, paying attention to my comments about feedback. What you will see is that most solid state amps don't use enough! I'm not one of those types that eschew feedback (although our tube amps don't use it); its just that I understand the simple fact that if you can't apply enough you'll be more likely to have a musical sounding amp if you don't apply any at all. Most solid state amps don't have enough because their designers didn't recognize this fact or simply didn't care. But there are a few that do and they have made exceptional products. High end audio is always about intention- not price.


I use recordings that I recorded myself. I have them on LP and CD; in this way I can know instantly how well a stereo is doing.
We're never going to agree but let me simply answer by asking a few questions.

- As a data point of preference, how many audiophiles in WBF own Classic Audio Loudspeakers and how many own the brands I stated earlier? And since many of these audiophile could own either why aren't they choosing Classic Audio Loudspeakers?

- What modern SS amps are you referring that "sound bright and harsh," because I can name dozens that don't and have exemplary low frequency control.

- Last but not least: What your not asking is - what is the detriment to speakers with 4 ohms impedance if they were designed to be 16 ohms? And if the benefit were so simple, why isn't everyone doing it?
 

Phantom-Audio

Well-Known Member
Apr 23, 2017
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www.phantom-audio.com
WBF :) No Idea who posts and under what name from my side of clients but below is my info.

2 Singaporian Clients of mine own the T1.5
1 In Malaysia (T1.5)
2 in Vietnam (T1.5 and T1.3)
2 In Indonesia (Both T1.3)
United Kingdom Has a T1.5 Unit but its packed up.


This is from me only.

I Know John Wolff is shifting bigger amounts of Stocks to Japan and China Constantly. These Audiophiles do not post on forums or social media and are private clients.

John also has made a lot more sales in the USA, I never do see his clients spending all day on forums posting so we will never know.
 
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