Ron’s New System

[Atmasphere]

Feedback is a negative sonic trait required only where the speaker needs more drive. Better speakers allow for zero feedback sets to drive them to glory. If the speaker is not efficient enough it will require feedback or worse, big push pull or big SS amp.

The statement above is misleading or simply wrong:
1) feedback is not a negative trait if properly applied. It often is improperly applied FWIW. I can explain in more detail.
2) The drive (in the context of your statement this appears to be simply power) the speaker needs has nothing to do with feedback in the amp
3) The quality of the speaker has nothing to do with whether it can be used with amps without feedback. The design of the speaker is a different matter!
4) the efficiency of the speaker (see #2) has nothing to do with whether it will need an amp with feedback or not.

The simple fact is some speakers do not use the Voltage drive principles; instead use the older (pre-1956 or so) Power drive principles. The latter comprise about 1% of total speakers made; nearly all of them offered to a rarefied market in high end. Put another way the speaker has to be designed to be driven by an amp of higher output impedance (no feedback) in order to sound right. If the speaker has controls on the back for adjusting midrange and tweeter output levels then the speaker can be adjusted to match the Voltage or Power response of the amp to the speaker's impedance. That is how it was done in the old days prior to the adoption of the Voltage drive rules which were meant to improve plug and play (no controls to adjust to get it to sound right).

Beyond this though (and I usually keep quiet on these things) I also don’t just see how the discussion (once again ) became hijacked by the weird random and compulsive anti SET rhetoric… never makes sense to me that SET haters are being triggered so constantly at seemingly every turn or most every topic to somehow drag the thread kicking and screaming back into let’s put the boot into what is just one niche of amplifier design… what are they ultimately threatened by and so aggressively and irrationally anti about, lord help us if they get involved in something that is actually vital or critical to world peace.

The 'anti SET rhetoric' is simply technical and engineering fact. I don't know of actual haters, nor any who are 'triggered' by SETs or some such. I personally feel its important to set the record straight (if you see what I did there) since so many people get, IMO, duped by them. If you are careful with selection you can find non-SET amps that sound better in every way, often for a fraction of the price and with more power.

Fact can be a harsh mistress. SETs don't stand up well to engineering fact. I've outlined why many times. If you need/want further iteration I'm happy to help out.

 

[Ron Resnick]

If the speaker has controls on the back for adjusting midrange and tweeter output levels then the speaker can be adjusted to match the Voltage or Power response of the amp to the speaker's impedance.

Do you mean the resulting output SPL of the midrange driver and of the tweeter driver?

Are you meaning to say here the same thing as if the speaker had controls for attenuating incoming amplifier power to the midrange and to the tweeter?

PS: I thought most, if not all, of your engineering criticisms of SET goes away if the SET is used to drive only about 200Hz and above?

 

[Atmasphere]

Do you mean the resulting output SPL of the midrange driver and of the tweeter driver?

Yes. Usually they have to be dialed back so the woofer can keep up. This is particularly true of horns.

Are you meaning to say here the same thing as if the speaker had controls for attenuating incoming amplifier power to the midrange and to the tweeter?

Not sure what you are asking.

PS: I thought most, if not all, of your engineering criticisms of SET goes away if the SET is used to drive only about 200Hz and above?

That certainly removes a major problem! So 'most' but not all. Despite that any zero feedback SET is a high distortion amp. About the only way to get around that is to run the amp at low power (I've mentioned that a lot too); 20-25% of full power at the maximum power level you would ever play. For nearly all SETs this means you must run horns.

But the thing is if you are looking for sound quality; if you want something musical you can often do just as well with a small push pull tube amp. In that way you can get around the low inductance at low frequencies thing and the amp might make an order of magnitude less distortion. Back in the 1950s there was a lot of work being done around developing low power pentodes that were meant to be very easy to drive. These pentodes allow for a small tube complement and also low distortion. The most famous of these is the EL84. A pair of those might make 15-20 Watts, 90-95% of which is usable power (meaning its musical) and its no worries in the bass department. I like the EL95 which is only good for 5 Watts PP or the 6AQ5 which is good for 10 (class A).

The thing is, amps based on those tubes tend to be less expensive. SETs of similar power might cost $20,000. This is where the Veblen Effect can have such a profound effect on the audiophile buyer and I've no doubt this is keeping the SET community going. But if you are able to step away from the Veblen influence you find that using such lower power pentodes actually make a lot of sense and allows you to get greater musicality. I don't hear any tradeoffs anyway and I know I'm not alone.

 

[morricab]

Do you mean the resulting output SPL of the midrange driver and of the tweeter driver?

Are you meaning to say here the same thing as if the speaker had controls for attenuating incoming amplifier power to the midrange and to the tweeter?

PS: I thought most, if not all, of your engineering criticisms of SET goes away if the SET is used to drive only about 200Hz and above?

A properly designed SET works just fine full range. His advocacy for PP tubes is, IMO, nonsense…as if us SET guys didn’t have PP tube amps before moving to SET for sonic preference. I have had little EL84 PP amps that ran Class A either UL or triode from Trafomatic, 300b push/pull Class A from VAC, Class A PP KT88 in triode etc. The SETs are simply better.

A friend had the Nagra VPAs (845 Class A PP) and they are good, but my SETs were better, both on my horns and on his Sonus Faber Olympica III speakers.

 

[the sound of Tao]

The 'anti SET rhetoric' is simply technical and engineering fact. I don't know of actual haters, nor any who are 'triggered' by SETs or some such. I personally feel its important to set the record straight (if you see what I did there) since so many people get, IMO, duped by them. If you are careful with selection you can find non-SET amps that sound better in every way, often for a fraction of the price and with more power.

Fact can be a harsh mistress. SETs don't stand up well to engineering fact. I've outlined why many times. If you need/want further iteration I'm happy to help out.

Relentlessly campaigning against competing product is such a clear and very direct conflict of interest for you and for your business and regardless of your regular denials this represents such an inconvenient truth for you… if your struggling to realise that I’m also happy to help out in return.

 

[Atmasphere]

Relentlessly campaigning against competing product is such a clear and very direct conflict of interest for you and for your business and regardless of your regular denials this represents such an inconvenient truth for you… if your struggling to realise that I’m also happy to help out in return.

I'd be happy to have your assistance.

The first thing you have to know about me though is I really don't care what amps people buy. I participate on these forums because I like audio, not because I make amps. People think we are an OTL manufacturer, but somehow we make PP amps, class D amps and have been building SET prototypes since 1995.

IOW I just do audio because I like it. People that know me know I'm not seriously concerned about making money in this field; IMO that's the wrong motivation.

So I don't see the conflict of interest. For me its more about informing the public and correcting misinformation. I know that to be a Sisyphean task so I don't obsess about it. But when I encounter obvious untruths and no-one is stepping up to the plate to correct them, it galls.

I've said nothing about SETs I can't back up. I will admit I've formed my viewpoint of them only in the last 30 years; they taught nothing about SETs at the university. But everything I've said is supported by engineering fact- things like how their output transformers tend to lack the inductance needed to play bass properly and so on. You might want to read this first before shooting the messenger.

 

[the sound of Tao]

So I don't see the conflict of interest.

That doesn’t mean that it’s not there.

 

[morricab]

That doesn’t mean that it’s not there.

You are dead on. He is twisting and cherry picking “facts” to defend his interests.

 

[Al M.]

That doesn’t mean that it’s not there.

Do you have any real technical arguments? All I'm reading is hurt feelings.

If Ralph is wrong, then you should have no problem proving it, no?

Not saying that SETs can't be great, I just don't see how your line of "argumentation" gets us anywhere.

 

[Ron Resnick]

Yes. Usually they have to be dialed back so the woofer can keep up.

Well, if we can put volume controls on drivers, and create our own frequency response contour, why does anybody have a problem with my woofer-cooking? Woofer-cooking raises the SPL of the woofer versus the midrange and the tweeter. Attenuating the midrange and the tweeter lowers the SPL of the midrange and the tweeter versus the woofer.

All we're doing is selecting an idiosyncratic SPL output from each driver and thus creating a custom tonal balance. I don't see any conceptual difference here.

But the thing is if you are looking for sound quality; if you want something musical you can often do just as well with a small push pull tube amp.

The thing is, amps based on those tubes tend to be less expensive. SETs of similar power might cost $20,000. This is where the Veblen Effect can have such a profound effect on the audiophile buyer and I've no doubt this is keeping the SET community going. But if you are able to step away from the Veblen influence you find that using such lower power pentodes actually make a lot of sense and allows you to get greater musicality. I don't hear any tradeoffs anyway and I know I'm not alone.

I don't understand why you don't consider wanting to avoid the crossover distortion of a push-pull design to be a legitimate preference.

These days solid-state amplifiers (other than Class D) have pulled far away in rising cost from almost any SET. If you're looking for Veblen purchases I think SETs is barking up the wrong tree.

 

[bonzo75]

Do you have any real technical arguments? All I'm reading is hurt feelings.

If Ralph is wrong, then you should have no problem proving it, no?

Not saying that SETs can't be great, I just don't see how your line of "argumentation" gets us anywhere.

Have you had arguments with technical designers of amps and turntables? They are always right about their designs. No SET designer is arguing on here, Ralph keeps on all threads

 

[morricab]

Do you have any real technical arguments? All I'm reading is hurt feelings.

If Ralph is wrong, then you should have no problem proving it, no?

Not saying that SETs can't be great, I just don't see how your line of "argumentation" gets us anywhere.

I have given Ralph plenty of technical arguments in the past but when he couldn’t take the heat he put me on ignore.

 

[the sound of Tao]

Do you have any real technical arguments? All I'm reading is hurt feelings.

If Ralph is wrong, then you should have no problem proving it, no?

Not saying that SETs can't be great, I just don't see how your line of "argumentation" gets us anywhere.

Al absolutely zero hurt feelings for me, that is just a misdirect… and it doesn’t negate my position.

The observations on there being a conflict of interest for Ralph in this is the technical argument I was addressing. Whether Ralph wants to ignore that essential conflict for him is all good. For me it just becomes flogging a dead horse going over the same rhetoric again and again and that was my original point.

 

[hopkins]

Have you had arguments with technical designers of amps and turntables? They are always right about their designs.

And as a result they rarely seem to talk to each other. I may be wrong. Maybe there's a dark web where all audio engineers hang out and do the same thing we do all day - argue...

 

[Atmasphere]

Well, if we can put volume controls on drivers, and create our own frequency response contour, why does anybody have a problem with my woofer-cooking? Woofer-cooking raises the SPL of the woofer versus the midrange and the tweeter. Attenuating the midrange and the tweeter lowers the SPL of the midrange and the tweeter versus the woofer.

All we're doing is selecting an idiosyncratic SPL output from each driver and thus creating a custom tonal balance. I don't see any conceptual difference here.

In the old days when most speakers had controls on the back, you set them not to preference (which, admittedly, that is what most people did) but rather to get the best interface between the amp and speaker.

I don't understand why you don't consider wanting to avoid the crossover distortion of a push-pull design to be a legitimate preference.

That is because the crossover distortion to which you refer really isn't a thing. Even if a PP amp is very lightly biased it can still be 100% free of any crossover distortion. The only time that really happens is when the amp is actually class C, which is to say one output cuts off before the other can get started. I know some will think of that as class B but it isn't. Further, any class D amp that uses an output filter will also be 100% immune to crossover distortion. So its really not a thing. I think that got started by marketing people who didn't know what they were talking about. They mislead a lot of people!

These days solid-state amplifiers (other than Class D) have pulled far away in rising cost from almost any SET. If you're looking for Veblen purchases I think SETs is barking up the wrong tree.

Yes, I was really only talking about tube amps of the same power at that point. Sorry I was not more specific!

No SET designer is arguing on here

I've been designing SETs since about 1995. So yes, there is.

The observations on there being a conflict of interest for Ralph in this is the technical argument I was addressing

What specifically is the conflict of interest? What is the technical argument that you are addressing?

And as a result they rarely seem to talk to each other. I may be wrong. Maybe there's a dark web where all audio engineers hang out and do the same thing we do all day - argue...

There sort of is! But once anyone is able to nail down the math or the like the conversation moves on.

 

[Al M.]

I have given Ralph plenty of technical arguments in the past but when he couldn’t take the heat he put me on ignore.

Maybe you can post some examples for such arguments.

 

[Atmasphere]

Maybe you can post some examples for such arguments.

I can see Brad's post from my email alert. His saying I could not take the heat is false. What really happened is I debunked his arguments, so he simply repeated them ad nauseam in a manner similar to propaganda. Part of his technique was to quote respected authors out of context so they seemed to support his position. Some of those authors were also simply incorrect or only partially correct.

On that last bit let me show an example of how a respected study can botch things up. Back in the 1960s there were a number of studies about the limitations of LP recordings. You can find them easily enough, especially if you hang out on pro-digital sites like Hydrogen. The problem, if you actually master LPs and know the theory behind them, is that most of the distortion of the LP occurs in playback, not record; LPs are actually quite low in distortion. If you look at those studies very little text is given to the provenance of the testing done in the study, for example the arm used, the cartridge used, how well the arm was set up, how well the phono section responded to tracking noise and other artifacts outside the audio band and so on. In addition, I think we can all agree that tonearms and cartridges were rather crude compared to what is available now, but those studies still get attention is if they are the real thing.

So one of Brad's arguments was about how harmonics generated by an amp should have an exponential decay as the order of the harmonic is increased. IIRC he mentioned Hiraga and Cheever (both respected authors). For best sound this is true. However, what he couldn't handle was the fact that there's always an exponent when there is an exponential curve. SETs produce, if properly set up, an exponential decay of harmonics based on a quadratic function (see Crowhurst and Putzeys' writings). But you can have an exponential decay based on a cubic function too, which occurs if the circuit is fully balanced. The latter is much lower distortion with higher ordered harmonics at a much lower level...

 

[morricab]

Maybe you can post some examples for such arguments.

Too long and tedious, sorry, you want to know…you dig.

However, if you look at his latest argument that crossover distortion is not really a thing, all you need to do is peruse Stereophile measurements to see it IS a thing…lots of modern amps have it and they are Class AB even , not Class B or even C as Ralph claims.

Even Douglas Self admits that crossover distortion is a thing and the one thing that can’t be solved other than full Class A or single ended amp design.

 

[morricab]

Amps that cancel even order harmonics do not correctly fit the pattern humans have evolved to filter out (our ear makes those harmonics and the brain filters them). Push pull amps cancel even harmonics by design. Fully balanced does the same thing. This was demonstrated by Boyk and Sussmann with modelling a differential circuit.

Keith Howard demonstrated that adding all odd harmonics to a digital file sounded significantly worse than a file adulterated with an exponential decay of even and odd harmonics.

 

[PeterA]

Too long and tedious, sorry, you want to know…you dig.

However, if you look at his latest argument that crossover distortion is not really a thing, all you need to do is peruse Stereophile measurements to see it IS a thing…lots of modern amps have it and they are Class AB even , not Class B or even C as Ralph claims.

Even Douglas Self admits that crossover distortion is a thing and the one thing that can’t be solved other than full Class A or single ended amp design.

Nelson Pass writes about crossover distortion when discussing his Class A designs in Leaving Class A. I know I always preferred the sound of his Class A XA.5 designs to his X designs, but boy were they hot. I now do prefer my SETs on very efficient corner horns. My SS Pass Aleph 3 amp sounded quite decent on my horns too. I would love to try some of FirstWatt SIT amps on the horns.