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#1
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
Trevor Wilson wrote: "Andre Jute" wrote in message Snipped, a barney of misunderstandings deliberately created by Arny Krueger in an effort to win a petty and spurious point. Out of that confusion Trevor offered to supply some page numbers from the RDH to prove that SET amps are less desirable than PP amps. That is the subject here. Let's keep keep it clean, fellers and come out swinging. SET v. PP, THE BIG FIGHT TONICHT First Trevor hauls out with his Langford-Smith, the voice of God, From the RDH 4. Section 13.1 Section 13.2 Section 13.4 (Not entirely necessary for this discussion) Section 13.5 (note the following words on page 574: "Push-pull operation tends always to reduce the effects of hum in either the grid bias or plate supply voltage.") Section 13.6 (Not strictly for discussion, because they speak of non-Triode amplifiers) Andre is on the canvas. You can't argue with a series of hammerblows like that. The ref makes him take a count of eight. Snips, which can be seen other threads. Trevor next asks us to address the following points I made about SE(T) amplifiers: --- * ALL SE amps suffer from even order harmonic distortion, which is automatically reduced by using push pull topology. IOW: All things being approximately equal (same output valves, high quality iron, good power supply, same bias current, etc) push pull will outperform SE. True. * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. True. * SE amps are MUCH less efficient that a similar power PP amp. Do we even need to say it? * SE amps, generally, exhibit higher levels of hum and noise than PP amps. Possibly true for the SE amps built by those you know, Trevor, or even some kind of a majority which can at a stretch permit you use the description "generally". * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. Also true, given that you add word generally to the first sentence. "Similar" is really a copout. Nobody who starts work on a SET amp has the constraints (usually of costs and a high power level) which generally hogtie PP design. -- Andre is staggering. His corner fingers the towel nervously. Wilson is prancing around, his fists already rising to take the victory on a technical (hee-hee) knockout. The truth is, Trevor, that my personal taste and the winner in blind tests with the musicians (still unspecified, if you don't mind) I like to use, as well as other qualified persons, is for small Class A push-pull trioded pentodes operated at low power with zero negative feedback. The best amp I ever designed is my T113 Class A PP EL34 in triode mode (its switchable, actually) with zero or very little negative feedback (also tunable in my own copy). That doesn't mean I abhor SET or solid state. I have and use both, too. Nor does the choice necessarily have anything to do with your reasons above. We shall return to those in a moment. At this point Trevor starts taking blows. In another thread Trevor wrote: **Why else would any sane designer choose SE(T) over PP? SE(T) offers no advantages. None whatsoever. PP is superior in every way. Aha. That's a different story: 1. Commercial reasons. A Japanese manufacturer I have worked with several times wanted a PSE 300B for about 16W. I wanted to give him trioded pentode PP for a better sound. His wife killed the discussion: We could never sell the better amp for half of what we can charge for the double-300B. I do as I am told. Herself has spoken. 2. Just because Andy Cowley is an unnecessarily abrasive asshole doesn't mean he is always wrong. He gave us a perfect reason for SET amps the other day: their transfer curve and interaction with the right speakers play right into the aural condition of the men who can afford them, who are largely middle-aged. 3. Well, actually, PP isn't superior in every way for every purpose. There are niches, and SET suits some of them very well indeed, thank you. Let's look again at your list of the shortcomings of SET, which I have admitted above, and see why none of those factors really matter in the end result. Now Andre is off the ropes, swinging. This is the same set of facts Trevor presented above, and Andre agreed to, seen in a new light: Andre offers Trevor a handicap: You can assume the worst condition for SE (zero negative feedback) and the best condition for PP (all the negative feedback even an incompetent designer may want), and I'll still whip your ass. Remember, Trevor, this isn't about which is better on the bench, this is about the rational right of audiophiles as listeners to choose their own topology. --- * ALL SE amps suffer from even order harmonic distortion, which is automatically reduced by using push pull topology. IOW: All things being approximately equal (same output valves, high quality iron, good power supply, same bias current, etc) push pull will outperform SE [on distortion]. There is no problem making an SE amp as flat as necessary even without NFB. You just choose sensitive speakers and then load up the impedance on the plate until its response is flat; all it costs is power turned into heat. At this point you discover that the PP amp with its feedback has disturbing odd harmonics. The argument isn't about added euphonics in the SE amp, it is that the wretched NFB has drained some glee from the PP amp. * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. True for those so thick they apply solid state paradigms to tube amp design. The solution is sensitive speakers and to design the amp so that it never comes within a hundred nautical miles of clipping. A 40W Pdmax 300B loaded to give under 4W of very flat power with a signal swing that never comes within some tens of volts from grid current, driving a speaker that will never demand a whole watt, is so far removed from this theoretical problem, we don't even discuss it much. It is only when a solid designer transferring in, or a newbie who still considers power a benefit blows in that we need to explain something this ingrained. * SE amps are MUCH less efficient that a similar power PP amp. Extravagantly true. So what? Hedonism has a price. * SE amps, generally, exhibit higher levels of hum and noise than PP amps. Quite untrue in my experience. There is no intrinsic reason an SE amp built by someone who knows that it won't benefit from the noise rejection PP amps have as birthright, should not be so designed as to minimize the disadvantage. I have reviewed several American and Far Eastern PP amps that have more him and general **** than any of my SE amps, and the price difference wasn't so huge in all cases (I admit, in most the price difference was large) * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. I repeat: Also true, given that you add word generally to the first sentence. "Similar" is really a copout. Nobody who starts work on a SET amp has the constraints (usually of costs and a high power level) which generally hogtie PP design. I'm going to leave Patrick argue this one with you. Didn't we have some private correspondence about this late last year, Patrick? Look it up: I thought you were admirably concise and to the point. -- There are some unique advantages to SET amps. One important one is that they naturally operate in Class A with only natural feedback (internal to tube as contrasted with added NFB), whereas the temptation in PP amps is always more power in Class A/B which never sounds quite as pleasing. I hope I have demonstrated that SET amplifiers are a perfectly legitimate choice even though I agree with you that a PP amp (strictly of the Class A1, ZNFB provenance, of course) will always be a technically better amp. The scorers are at work... Quoted text by Trevor Wilson www.rageaudio.com.au Counterargument by Andre Jute Visit Jute on Amps at http://members.lycos.co.uk/fiultra/ wonderfully well written and reasoned information for the tube audio constructor" John Broskie TubeCAD & GlassWare "an unbelievably comprehensive web site containing vital gems of wisdom" Stuart Perry Hi-Fi News & Record Review |
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#2
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
On 18 Dec 2005 19:53:41 -0800, "Andre Jute" wrote:
* SE amps are MUCH less efficient that a similar power PP amp. Extravagantly true. So what? Perhaps if we were to frame the argument to specifically exclude issues of efficiency, cost, and suitability for use in 7.1 channel Home Theaters... Those issues make a short and trivial discussion. On this newsgroup, other things actually matter. Visit Jute on Amps at http://members.lycos.co.uk/fiultra/ BTW, perusing your website, I discovered the Gazelle Toulouse. Curse you, Andre Jute. How the heck am I supposed to get one here to East Jesus, Arkansas? The web site doesn't even mention American distribution, and I've never seen one (but it seems Just Right). Drat, and a curse on both our houses. Thanks, as always, Chris Hornbeck "Angels are, dreaming of you" - Sonic Youth |
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#3
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
"Andre Jute" wrote in message oups.com... Trevor Wilson wrote: "Andre Jute" wrote in message Snipped, a barney of misunderstandings deliberately created by Arny Krueger in an effort to win a petty and spurious point. Out of that confusion Trevor offered to supply some page numbers from the RDH to prove that SET amps are less desirable than PP amps. That is the subject here. Let's keep keep it clean, fellers and come out swinging. SET v. PP, THE BIG FIGHT TONICHT First Trevor hauls out with his Langford-Smith, the voice of God, From the RDH 4. Section 13.1 Section 13.2 Section 13.4 (Not entirely necessary for this discussion) Section 13.5 (note the following words on page 574: "Push-pull operation tends always to reduce the effects of hum in either the grid bias or plate supply voltage.") Section 13.6 (Not strictly for discussion, because they speak of non-Triode amplifiers) Andre is on the canvas. You can't argue with a series of hammerblows like that. The ref makes him take a count of eight. Snips, which can be seen other threads. Trevor next asks us to address the following points I made about SE(T) amplifiers: --- * ALL SE amps suffer from even order harmonic distortion, which is automatically reduced by using push pull topology. IOW: All things being approximately equal (same output valves, high quality iron, good power supply, same bias current, etc) push pull will outperform SE. True. **Good to see you are displaying the kind of honesty not present in some others I've discussed this topic with. * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. True. **Good to see you are displaying the kind of honesty not present in some others I've discussed this topic with. * SE amps are MUCH less efficient that a similar power PP amp. Do we even need to say it? **Apparently we do. Patrick Turner has proclaimed that none of what I wrote is correct. * SE amps, generally, exhibit higher levels of hum and noise than PP amps. Possibly true for the SE amps built by those you know, Trevor, or even some kind of a majority which can at a stretch permit you use the description "generally". **I used the term "generally", since it is possible to build a crappy PP amp and a relatively good SE(T) amp, where the PP amp is inferior. However, all things being equal (or as equal as can be, PP will be superior). * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. Also true, given that you add word generally to the first sentence. "Similar" is really a copout. Nobody who starts work on a SET amp has the constraints (usually of costs and a high power level) which generally hogtie PP design. **One must compare apples with apples. -- Andre is staggering. His corner fingers the towel nervously. Wilson is prancing around, his fists already rising to take the victory on a technical (hee-hee) knockout. The truth is, Trevor, that my personal taste and the winner in blind tests with the musicians (still unspecified, if you don't mind) I like to use, **I'll tackle this point, right here and now. The mere fact that a person is a musician cuts no mustard with anyone. A musician, depending on his/her particular talent, has some excellent abilities. The ability to judge how realistic a sound reproduction system is (the goal of high fidelity) not one of them. Dexterity, the ability to follow music sheets and other factors are relevant for musicians. Anecdote: A few years ago, I attended the sound system owned by one of Australia's foremost, most respected classical musicians. The man was not old. He is also one of the nation's best conductors. That puts him way ahead of the vast majority of musos, given he actually hears the entire orchestra, rather than listening only to the (say) squeaking of the first violins. Most musos only get to listen to their own instruments clearly. Anyway, I walked in, put on an unfamiliar disk and was instantly struck by the obvious problems in the system. First and foremost, one of the speakers was out of phase. After rectifying this fault, I asked the man what he thought of the (considerable) improvement. His response: "I don't hear any difference". Hmmmmm.. One of my old school mates played in the Sydney Symphony Orchestra's First Violins. He listens to his system with the tone controls (??!!!) turned all the way up. Don't talk to me about musicians. as well as other qualified persons, is for small Class A push-pull trioded pentodes operated at low power with zero negative feedback. **Good for them. I'm not disucssing preference. I'm discussing high fidelity. IE: What sounds closer to the real event. The best amp I ever designed is my T113 Class A PP EL34 in triode mode (its switchable, actually) with zero or very little negative feedback (also tunable in my own copy). **I have no issue with PP, of any persuasion. PP eliminates or reduces most of the problems associated with SE(T). That doesn't mean I abhor SET or solid state. I have and use both, too. Nor does the choice necessarily have anything to do with your reasons above. We shall return to those in a moment. At this point Trevor starts taking blows. **Oh, dream on. In another thread Trevor wrote: **Why else would any sane designer choose SE(T) over PP? SE(T) offers no advantages. None whatsoever. PP is superior in every way. Aha. That's a different story: 1. Commercial reasons. A Japanese manufacturer I have worked with several times wanted a PSE 300B for about 16W. I wanted to give him trioded pentode PP for a better sound. His wife killed the discussion: We could never sell the better amp for half of what we can charge for the double-300B. I do as I am told. Herself has spoken. 2. Just because Andy Cowley is an unnecessarily abrasive asshole doesn't mean he is always wrong. He gave us a perfect reason for SET amps the other day: their transfer curve and interaction with the right speakers play right into the aural condition of the men who can afford them, who are largely middle-aged. 3. Well, actually, PP isn't superior in every way for every purpose. There are niches, and SET suits some of them very well indeed, thank you. Let's look again at your list of the shortcomings of SET, which I have admitted above, and see why none of those factors really matter in the end result. Now Andre is off the ropes, swinging. This is the same set of facts Trevor presented above, and Andre agreed to, seen in a new light: Andre offers Trevor a handicap: You can assume the worst condition for SE (zero negative feedback) and the best condition for PP (all the negative feedback even an incompetent designer may want), and I'll still whip your ass. **Nope. If your hypothetical SE(T) amp uses no Global NFB, then so too does the hypothetical PP amp. Same output tubes, same Class A bias, similarly sized power supply, etc, etc. Let's compare apples with apples, not apples with bricks. Remember, Trevor, this isn't about which is better on the bench, this is about the rational right of audiophiles as listeners to choose their own topology. **You mean: "The irrational right of some nut-jobs to promote dodgy technology to those who know no better." --- * ALL SE amps suffer from even order harmonic distortion, which is automatically reduced by using push pull topology. IOW: All things being approximately equal (same output valves, high quality iron, good power supply, same bias current, etc) push pull will outperform SE [on distortion]. There is no problem making an SE amp as flat as necessary even without NFB. **Yes, there is. You just choose sensitive speakers **Hang on a sec. You've just shifted the goalposts. You're saying that SE(T) amps are OK, but you must use certain speakers. I presume you're going to tell me that they need to provide a perfectly resistive load too? Don't forget, that pesky power problem associated with SE(T) amps. and then load up the impedance on the plate until its response is flat; all it costs is power turned into heat. At this point you discover that the PP amp with its feedback has disturbing odd harmonics. The argument isn't about added euphonics in the SE amp, it is that the wretched NFB has drained some glee from the PP amp. **There is no necessity for a PP amp to use Global NFB. If you want to compare non-Global NFB SE(T) amps, then compare them with a similarly configured PP amp. * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. True for those so thick they apply solid state paradigms to tube amp design. **Nope. True for ALL SE amps. Every one. It's just that the distortion levels of SET amps (and most others which eschew the use of Global NFB) increases distortion somewhat gradually. The end result is still the same. Halve the load impedance and halve the power. Excatly the reverse of a theoretically 'perfect amplifier' and far from what almost any PP amp (even those which use no Global NFB) will do. IOW: SE(T) amps are about as anti-high fidelity as it is possible to get. The solution is sensitive speakers and to design the amp so that it never comes within a hundred nautical miles of clipping. **Cop out. It is desirable to prevent any amplifier from clipping. A 40W Pdmax 300B loaded to give under 4W of very flat power with a signal **Which becomes 2 Watts, when the load is 4 Ohms and 1 Watt, when the load falls to 2 Ohms. swing that never comes within some tens of volts from grid current, driving a speaker that will never demand a whole watt, is so far removed from this theoretical problem, we don't even discuss it much. It is only when a solid designer transferring in, or a newbie who still considers power a benefit blows in that we need to explain something this ingrained. * SE amps are MUCH less efficient that a similar power PP amp. Extravagantly true. So what? Hedonism has a price. **I was thinking that ignorance has it's price. * SE amps, generally, exhibit higher levels of hum and noise than PP amps. Quite untrue in my experience. **Go read the RDH4. It's all there. There is no intrinsic reason an SE amp built by someone who knows that it won't benefit from the noise rejection PP amps have as birthright, should not be so designed as to minimize the disadvantage. I have reviewed several American and Far Eastern PP amps that have more him and general **** than any of my SE amps, and the price difference wasn't so huge in all cases (I admit, in most the price difference was large) **There you go again: Comparing apples with bricks. * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. I repeat: Also true, given that you add word generally to the first sentence. "Similar" is really a copout. Nobody who starts work on a SET amp has the constraints (usually of costs and a high power level) which generally hogtie PP design. **All one needs to do is to put as much effort into a PP design that one puts into the SET design and the superiority will be blindingly obvious. I'm going to leave Patrick argue this one with you. Didn't we have some private correspondence about this late last year, Patrick? Look it up: I thought you were admirably concise and to the point. **Patrick lacks the balls to argue with me. -- There are some unique advantages to SET amps. One important one is that they naturally operate in Class A **Er, no. They MUST operate in Class A. MUST, MUST MUST. BIG diference. A PP deisgner can choose any Class of operation, from Class B all the way to pure Class A. Moreover, since the efficiency level is significantly higher, more Class A can be run, so that operating into lower impedance loads still affords some Class A operation, if that is desired. The SE(T) designer is stuck with whatever he/she can manage. with only natural feedback (internal to tube as contrasted with added NFB), whereas the temptation in PP amps is always more power in Class A/B which never sounds quite as pleasing. **Again: If you want to compare zero Global NFB designs, then do so. Don't compare apples with bricks. I hope I have demonstrated that SET amplifiers are a perfectly legitimate choice **Only for the ignorant. even though I agree with you that a PP amp (strictly of the Class A1, ZNFB provenance, of course) will always be a technically better amp. **Thank you. THAT is my point. The scorers are at work... **I suspect I know what the result will be. -- Trevor Wilson www.rageaudio.com.au |
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#4
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
In article .com, "Andre
Jute" wrote: Trevor Wilson wrote: "Andre Jute" wrote in message * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. True. This is a crock, and is actually False if everything else is equal, namely the PP amp uses the same tubes under the same operating conditions as the SE amp. A severe blow to Trevor * SE amps are MUCH less efficient that a similar power PP amp. Do we even need to say it? No, SE amps are only marginally less efficient than PP amps using the same tubes under the same class A operating conditions. * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. Also true, given that you add word generally to the first sentence. "Similar" is really a copout. Nobody who starts work on a SET amp has the constraints (usually of costs and a high power level) which generally hogtie PP design. Again this is a crock and is False, PP or SE doesn't make any difference as long as the tubes and operating conditions are the same. The SE will actually have a better damping factor than a similar PP amp operating class AB. Trevor loses the match. Regards, John Byrns Surf my web pages at, http://users.rcn.com/jbyrns/ |
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#6
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
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#7
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
Chris Hornbeck wrote:
On 18 Dec 2005 19:53:41 -0800, "Andre Jute" wrote: [ Trevor Wilson wrote:] * SE amps are MUCH less efficient that a similar power PP amp. Extravagantly true. So what? Perhaps if we were to frame the argument to specifically exclude issues of efficiency, cost, and suitability for use in 7.1 channel Home Theaters... Those issues make a short and trivial discussion. On this newsgroup, other things actually matter. Chris, darling, WTF do you agree with, Trevor the Efficient or SET the Hedonist or George Lucas the Destroyer? Or did I get it right first time, this is a refined Plainsman's way of expressing contempt for the destructive power of popular culture? Andre Jute |
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#8
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
John Byrns wrote: In article .com, "Andre Jute" wrote: Trevor Wilson wrote: "Andre Jute" wrote in message * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. True. This is a crock, and is actually False if everything else is equal, namely the PP amp uses the same tubes under the same operating conditions as the SE amp. A severe blow to Trevor * SE amps are MUCH less efficient that a similar power PP amp. Do we even need to say it? No, SE amps are only marginally less efficient than PP amps using the same tubes under the same class A operating conditions. * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. Also true, given that you add word generally to the first sentence. "Similar" is really a copout. Nobody who starts work on a SET amp has the constraints (usually of costs and a high power level) which generally hogtie PP design. Again this is a crock and is False, PP or SE doesn't make any difference as long as the tubes and operating conditions are the same. The SE will actually have a better damping factor than a similar PP amp operating class AB. Trevor loses the match. Regards, John Byrns Surf my web pages at, http://users.rcn.com/jbyrns/ With my manager and my seconds holding me up, it looks like I won by a knockout in the first round anyway! Andre Jute Having fun rigging the betting |
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#9
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
"Andre Jute" wrote in message oups.com... With my manager and my seconds holding me up, it looks like I won by a knockout in the first round anyway! **Huh? In what universe? You have yet to address the points I made in my second post. -- Trevor Wilson www.rageaudio.com.au |
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#10
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
"Jon Yaeger" wrote in message ... in article , Andre Jute at wrote on 12/18/05 10:53 PM: This isn't much of contest; the fight was rigged from the git-go. **Yep. PP is a hands-down winner. Andre has moved the goalposts, but still can't mount a credible argument, short of: "But I know a bunch of musicians who prefer the sound of SET amplifiers." IOW: No argument at all. In fact, he has already acknowledged that most of my points are correct. IMO, he has yet to disprove any one of them. Properly designed SE amps can do nice things in the mid and upper registers, with very efficient low-wattage speakers. **And PP amps can do nice things in the midrange with efficient (and innefficient) speakers. Veen better, they can do nice things in the LF and HF to boot. -- Trevor Wilson www.rageaudio.com.au |
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#11
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
Andre Jute wrote [snip for brevity]
There are just three differences between SE and PP, and none are worth fighting about. First, a SE amp needs a gap in the OPT. In general, this results in lower primary inductance, and therefore curtailed bass, all other things being equal. This is not just a matter of common practice, because if the SE OPT were to equal the inductance of the PP, it would be much bigger, and suffer in terms of primary capacitance, leakage inductance, or both, thus curtailing the top end. Hence the difference here is fundamental. It is possible to use a gapped OPT for PP, so some advantages of the gap are transferable from one topology to the other. One property of the SE OPT is necessarily unique, however: it is biased into the most linear part of the BH curve. Any advantages of zero gap belong to PP alone. Second, the opposition of distortion and power supply products in PP. Assuming both have perfect power supplies, this boils down to a matter of quantity v quality of distortion, and ultimately is a matter of individual perception. Third, a good PP amp will enter AB operation at the same point that an equally good SE amp begins to clip. All the other stuff is about incidental, rather than fundamental, difference. Without a budget, there can be no sensible argument. cheers, Ian |
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#12
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
Andre Jute wrote: With my manager and my sock-puppets holding me up, it looks like I won by a knockout in the first round anyway! In your oafish disease-riddled mind I guess. Graham |
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#13
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
Trevor Wilson wrote:
"Andre Jute" wrote in message Trevor Wilson wrote: Patrick Turner has proclaimed that none of what I wrote is correct. All of this depends on the assumptions under which we are operating. You and Patrick may have less bother if you agree ground rules. This isn't a knock. I made the same error: I thought you and I had a set of assumptions agreed but it turns out not to be so when you say: However, all things being equal (or as equal as can be, PP will be superior). The horses for courses assumption, supported by the above, which I thought we had in common, is totally reversed in this exchange: Andre offers Trevor a handicap: You can assume the worst condition for SE (zero negative feedback) and the best condition for PP (all the negative feedback even an incompetent designer may want), and I'll still whip your ass. **Nope. If your hypothetical SE(T) amp uses no Global NFB, then so too does the hypothetical PP amp. Same output tubes, same Class A bias, similarly sized power supply, etc, etc. Let's compare apples with apples, not apples with bricks. Oh dear. I was operating under assumption that all things are not equal, not in the sense you elaborate above, that instead we are positing a comparison between median real-life amps. For instance, a modern ZNFB SET amp is deliberately designed to be much flatter than say fifty years ago, while the PP amp will have much more power (than the SET) with NFB silencing it. That changes my view on these matters that you raise, even in the first (strictly technical) round where I agreed with you, the second harmonics matter excepted. I read "similar" in a very much wider context of merely meaning "competent" or "of presently acceptable design", whereas you (and John and Chris) are reading it as literal sameness, including precisely the same tubes at precisely the same power output with precisely the same NFB, which you specifically state later on. **There is no necessity for a PP amp to use Global NFB. If you want to compare non-Global NFB SE(T) amps, then compare them with a similarly configured PP amp. If that sort of *equality*, meaning precise similarity to the greatest possible extent achievable, is the rule under which we're operating (a stupid ****ing way to proceed, even if more scientific--nobody would choke a PP amp down like that), I must be a greek giver. I cannot agree with you an any point in the first round except the second harmonic. * ALL SE amps suffer from even order harmonic distortion, which is automatically reduced by using push pull topology. IOW: All things being approximately equal (same output valves, high quality iron, good power supply, same bias current, etc) push pull will outperform SE. True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. But in this contest, with both amps operating under the same conditions, they are assumed to be designed so that the harmonics of any nature are imperceptible. * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. When the two amps use the same tubes under the same operating conditions? Rubbish. That's why I tried to give your beloved PP a break so you could win something in the first round. * SE amps are MUCH less efficient that a similar power PP amp. In Class A? Replace the loud "much" with a whimpered space, and I'll agree. * SE amps, generally, exhibit higher levels of hum and noise than PP amps. This is entirely an irrelevance in modern amps where we know how to reduce levels of hum and noise to better than acceptable levels. It is a petty point applicable only to the cheapest commercial amps. We're talking about a different class of amp. * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. I withdraw my original highly qualified agreement, given under a false assumption of amps of standard design for their class rather than artificially similar as in the new rules. **One must compare apples with apples. Have it your way, Trevor. In that case, under the present rules your statement is incorrect. **I have no issue with PP, of any persuasion. PP eliminates or reduces most of the problems associated with SE(T). But Trevor, there aren't any problems remaining. Under the new rules of equality, where I am defending ZNFB Class A SET against Trevor's ZNFB Class A PP, push pull topology simply does not have any technical advantage over SET, and in real life where the PP amp would use beam or pentode tubes and the SET a DHT, the SET has all the advantages of its built-in NFB. -- Trevor Wilson www.rageaudio.com.au You shouldn't have changed the rules Trevor. Under the new rules you cannot prove superiority for PP amps. Not that anyone changes behaviour, of course. You will play your beloved PP and I will play my beloved PP, and my beloved SET, and my beloved solid state. We'll both still be listening to the speakers, not the amps. Thanks for sparring. Andre Jute |
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#14
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SET v. PP, the big fight tonight
I thought we were having a quiet discussion, Trevor. Now I discover you
gloating that you "won" something. We can safely leave that sort of behaviour to trash like Poopie Stevenson. But I answered all the points in this letter in the one I sent in reply to another. We should do this again sometime. -- Andre Jute PS Jon, I hope you don't suspect me of rigging the contest. I bent over backwards to give Trevor an unfair advantage. Like a gentleman he declined it. Trevor Wilson wrote: "Jon Yaeger" wrote in message ... in article , Andre Jute at wrote on 12/18/05 10:53 PM: This isn't much of contest; the fight was rigged from the git-go. **Yep. PP is a hands-down winner. Andre has moved the goalposts, but still can't mount a credible argument, short of: "But I know a bunch of musicians who prefer the sound of SET amplifiers." IOW: No argument at all. In fact, he has already acknowledged that most of my points are correct. IMO, he has yet to disprove any one of them. Properly designed SE amps can do nice things in the mid and upper registers, with very efficient low-wattage speakers. **And PP amps can do nice things in the midrange with efficient (and innefficient) speakers. Veen better, they can do nice things in the LF and HF to boot. -- Trevor Wilson www.rageaudio.com.au |
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#16
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SET v. PP, the big fight tonight
in article , Andre Jute
at wrote on 12/19/05 5:38 AM: I thought we were having a quiet discussion, Trevor. Now I discover you gloating that you "won" something. We can safely leave that sort of behaviour to trash like Poopie Stevenson. But I answered all the points in this letter in the one I sent in reply to another. We should do this again sometime. -- Andre Jute PS Jon, I hope you don't suspect me of rigging the contest. I bent over backwards to give Trevor an unfair advantage. Like a gentleman he declined it. *** I'm not accusing you of that. I'm afraid physics has called this one long ago . . . . |
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#17
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SET v. PP, the big fight tonight
In article , "Ian Iveson"
wrote: Third, a good PP amp will enter AB operation at the same point that an equally good SE amp begins to clip. This is only true if the PP amp is biased at a lower standing current level than the SE amp, or if the driver stage can supply the grid current required for class AB2 operation. Regards, John Byrns Surf my web pages at, http://users.rcn.com/jbyrns/ |
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#18
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SET v. PP, the big fight tonight
John Byrns wrote
Third, a good PP amp will enter AB operation at the same point that an equally good SE amp begins to clip. This is only true if the PP amp is biased at a lower standing current level than the SE amp, or if the driver stage can supply the grid current required for class AB2 operation. You're right. Assuming that the SE is biased halfway between cutoff and grid current. Let's say in that case, all things being equal, that the PP will enter AB2 at the same point that the SE begins to clip. If neither is capable of sustaining grid current, then we would be comparing one kind of distortion with another. Again, that would be a matter of perception and preference I suppose. It doesn't seem fair to compare an AB2-capable PP with a SE that can't cope with grid current, and yet if the SE is capable of A2, then it would be biased at a higher standing current than the AB2 PP. So if the "all other things being equal" is to include the operating point, then really you have to compare SE A with PP AB2. A2 PP seems perverse somehow. cheers, Ian |
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#19
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SET v. PP, the big fight tonight
"Andre Jute" wrote in message ups.com... I thought we were having a quiet discussion, Trevor. Now I discover you gloating that you "won" something. **Did I say that? Cite please. I said that PP was the winner. Not me. I am quoting facts. You're the one involved in what you image to be some kind of boxing match. We can safely leave that sort of behaviour to trash like Poopie Stevenson. But I answered all the points in this letter in the one I sent in reply to another. **Ah, the Patrick Turner response. IOW: NO response at all. We should do this again sometime. -- Andre Jute PS Jon, I hope you don't suspect me of rigging the contest. **And yet, you did. YOu assumed that ALL PP amps uise Global NFB and ALL SE(T) amps use none. A rather shabby attmpet to shift the goalposts. If you're comparing apples then you should be using apples, not bricks. I bent over backwards to give Trevor an unfair advantage. Like a gentleman he declined it. **Utter, banal nonsense. Comparisons should be fair and reasonable. IOW: Compare apples with apples, not apples and bricks. -- Trevor Wilson www.rageaudio.com.au |
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#20
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
"Andre Jute" wrote in message oups.com... Trevor Wilson wrote: "Andre Jute" wrote in message Trevor Wilson wrote: Patrick Turner has proclaimed that none of what I wrote is correct. All of this depends on the assumptions under which we are operating. You and Patrick may have less bother if you agree ground rules. This isn't a knock. I made the same error: I thought you and I had a set of assumptions agreed but it turns out not to be so when you say: However, all things being equal (or as equal as can be, PP will be superior). The horses for courses assumption, supported by the above, which I thought we had in common, is totally reversed in this exchange: Andre offers Trevor a handicap: You can assume the worst condition for SE (zero negative feedback) and the best condition for PP (all the negative feedback even an incompetent designer may want), and I'll still whip your ass. **Nope. If your hypothetical SE(T) amp uses no Global NFB, then so too does the hypothetical PP amp. Same output tubes, same Class A bias, similarly sized power supply, etc, etc. Let's compare apples with apples, not apples with bricks. Oh dear. I was operating under assumption that all things are not equal, not in the sense you elaborate above, that instead we are positing a comparison between median real-life amps. **That would be a really dumb way to compare topologies. If you are comparing topologies (which we are) then we need to eliminate as many variables as it is possible to do. Global NFB vs. zero Global NFB is a HUGE variable. For instance, a modern ZNFB SET amp is deliberately designed to be much flatter than say fifty years ago, while the PP amp will have much more power (than the SET) with NFB silencing it. That changes my view on these matters that you raise, even in the first (strictly technical) round where I agreed with you, the second harmonics matter excepted. I read "similar" **When I say "similar" is mean SIMILAR. All the way down to the type of iron used, tube types, resistor types, HT Voltages, bias currents and NFB arrangements. in a very much wider context of merely meaning "competent" or "of presently acceptable design", whereas you (and John and Chris) are reading it as literal sameness, including precisely the same tubes at precisely the same power output with precisely the same NFB, which you specifically state later on. **There is no necessity for a PP amp to use Global NFB. If you want to compare non-Global NFB SE(T) amps, then compare them with a similarly configured PP amp. If that sort of *equality*, meaning precise similarity to the greatest possible extent achievable, is the rule under which we're operating (a stupid ****ing way to proceed, **Huh? If you're comparing output stage topologies (which we are) then it is the ONLY way to proceed. Otherwise, you're just comparing different iron, different NFB schemes, whatever. even if more scientific--nobody would choke a PP amp down like that), I must be a greek giver. I cannot agree with you an any point in the first round except the second harmonic. **Then you need to do more reading. Or testing. You choose. * ALL SE amps suffer from even order harmonic distortion, which is automatically reduced by using push pull topology. IOW: All things being approximately equal (same output valves, high quality iron, good power supply, same bias current, etc) push pull will outperform SE. True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? But in this contest, with both amps operating under the same conditions, they are assumed to be designed so that the harmonics of any nature are imperceptible. **A bold assumption. Under what conditions can your SET amp acheive that? * ALL SE amps suffer appallingly bad load tolerance. IOW: A 20 SE amp (at or near clipping) will deliver 10 Watts @ 4 Ohms, 5 Watts @ 2 Ohms and so on. Unless the user has an almost resistive load, then severe power problems can be expected. This problem can be eliminated by using push pull topology. When the two amps use the same tubes under the same operating conditions? Rubbish. That's why I tried to give your beloved PP a break so you could win something in the first round. **Huh? Let me spell it out for you: When your SE amp (of ANY variety) hits it's maximum peak current, not only does it cease to be operating in Class A, but it ceases to be an amplifier. *ANY* PP amp, will still continue to act as an amplifier, even after it reaches a point where more peak current is demanded, beyond it's bias point. It simply begins operation in Class B. IOW: The worst case scenario will be that a PP amp will deliver approximately similar power levels, even as the load impedance is halved. A theoretically 'perfect' amplifier will, of course, double it's power as the load impedance is successively halved. Therefore, *any* SE(T) amplifier is the complete antithesis of the perfect amplifier. * SE amps are MUCH less efficient that a similar power PP amp. In Class A? **Yes. Want that RDH4 quote again? Replace the loud "much" with a whimpered space, and I'll agree. * SE amps, generally, exhibit higher levels of hum and noise than PP amps. This is entirely an irrelevance in modern amps where we know how to reduce levels of hum and noise to better than acceptable levels. It is a petty point applicable only to the cheapest commercial amps. We're talking about a different class of amp. **Fair enough. Nevertheless, it is a fact of life that PP confers an automatic reduction in hum an noise. * SE amps have a lower damping factor than a similar PP amp. This may lead to audible frequency response problems, within the audio range. I withdraw my original highly qualified agreement, given under a false assumption of amps of standard design for their class rather than artificially similar as in the new rules. **One must compare apples with apples. Have it your way, Trevor. In that case, under the present rules your statement is incorrect. **Huh? **I have no issue with PP, of any persuasion. PP eliminates or reduces most of the problems associated with SE(T). But Trevor, there aren't any problems remaining. Under the new rules of equality, where I am defending ZNFB Class A SET against Trevor's ZNFB Class A PP, push pull topology simply does not have any technical advantage over SET, and in real life where the PP amp would use beam or pentode tubes and the SET a DHT, the SET has all the advantages of its built-in NFB. **I suggest you read the sections I've previously cited from the RDH4. Your knowledge is seriously deficient. Unless, of course, you feel that the autor of the RDH4 was wrong. -- Trevor Wilson www.rageaudio.com.au You shouldn't have changed the rules Trevor. Under the new rules you cannot prove superiority for PP amps. **I changed nothing. When comparing topolgies, it is appropriate to compare ONLY the topolgy. Not that anyone changes behaviour, of course. You will play your beloved PP and I will play my beloved PP, and my beloved SET, and my beloved solid state. We'll both still be listening to the speakers, not the amps. Thanks for sparring. **Sparring? What's with boxing metaphors? -- Trevor Wilson www.rageaudio.com.au |
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#21
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson"
wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Can you say, "Strawman"? |
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#22
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
dave "deaf" weil wrote :
On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson" wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Please Sir, excuse Dave. He is the only deaf audio-reviewer around here. Dave I have already told you that because of your hearing problems you should stay off the discussions about HiFi... What about a little politic discussion with McKelvy on RAO, eh Dave ? -- "Nobody seemes to have actaully read what i wrote. But what's new around here?" Dave Weil, Sun, 05 Oct 2003 00:57:15 |
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#23
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
dave weil wrote: On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson" wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Can you say, "Strawman"? To be fair, Dave, he talks about "greater fidelity", thought the answer is still the same. Here is an experiment: Set up two amplifiers exactly the same in all respects except one is PP and the other is SE, with just enough distortion on each amplifier to be perceptible to a refined listener. Spin a disc. Now the SE amp will give you the warm glow that the same music originally gave you in the concert hall. The PP amp will have that disturbing edge of odd harmonics. Reduce the level of distortion a little to below perception. Now the SE amp still sounds great and you can live with for a long time. But the PP amp is not so comfortable after a disc or two; it demands attention with a certain edgy quality. Which offers a window on the concert hall? Which is the amp you want to live with? I would have given Trevor that one were he not trying to have it both ways, on the one hand reproaching me for trying to cut his champion a break by giving it NFB, on the other deceitfully claiming above that despite making the amps precisely similar, which must surely include the same level of THD (it would be hard to give them the same harmonics spectrum!), the SE amp would still have "higher levels of distortion". xTHD is xTHD, Trevor; all that is different is the spectrum of harmonics. But sure, I include in my definition of "greater fidelity" the quality of distortion. When THD is levelpegged, the SE amp must produce a superior quality result to that of the PP amp. (1) You can't have it both ways, Trevor! Andre Jute (1) And, as Ruud Broens has already pointed out, odd harmonics are so disturbing that even where the THD of a PP amplifier is lower than that of an otherwise similar SE amp (Trevor's case above), the PP amp is perceived as noisy whereas the SE amp is perceived as blamelessly silent. The proof of the pudding is in the eating. |
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#24
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
"Andre Jute" wrote in message oups.com... dave weil wrote: On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson" wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Can you say, "Strawman"? To be fair, Dave, he talks about "greater fidelity", thought the answer is still the same. Here is an experiment: Set up two amplifiers exactly the same in all respects except one is PP and the other is SE, with just enough distortion on each amplifier to be perceptible to a refined listener. Spin a disc. **I would accept that both amps display similar levels of odd order distortion, at their rated power outputs. Say: 10 Watts(@ 8 Ohms) for the SE and 20 Watts (@ 8 Ohms) for the PP. In that case, the SE amp will be exhibiting MUCH higher levels of even order distortion than the PP amp. More importantly, when the impedance of that speaker falls to (say) 4 Ohms, the SE amp will fall on it's face, whist the PP amp will continue to deliver more power (under most circumstances). Here is the impedance curve of a (admittedly diabolical) 4 Ohms speaker: www.rageaudio.com.au/kappa9.jpg Configured for the 4 Ohm tap, a 10 Watt SE amp will be delivering around 2 Watts at the impedance dips. The PP amp, OTOH, has a much better chance of maintaining output Voltage, regardless of the impedance of the load. The SE amp, despite heroic efforts to bolster power supplies, is inevitably limited by it's bias current. It is a major and fatal flaw on the road to high fidelity reproduction. Now the SE amp will give you the warm glow that the same music originally gave you in the concert hall. **Prove it. And forget about these musician friends. They are not necessarily the ultimate arbiters of accurate sound reproduction equipment. The PP amp will have that disturbing edge of odd harmonics. **The PP amp will exhibit similar levels of odd order harmonics. Reduce the level of distortion a little to below perception. Now the SE amp still sounds great and you can live with for a long time. But the PP amp is not so comfortable after a disc or two; it demands attention with a certain edgy quality. **Prove it. I don't know about you, but I listen to music at any (reasonable) level I want. Being forced to listen at incredibly low levels is quite an odd concept. Which offers a window on the concert hall? Which is the amp you want to live with? **The amp which: * Exhibits the lowest levels of (audible) distortion. * Is capable of driving real world, off the shelf loudspeakers. * Exhibits the most linear frequency response, when driving the above-mentioned loudspeakers. I would have given Trevor that one were he not trying to have it both ways, on the one hand reproaching me for trying to cut his champion a break by giving it NFB, on the other deceitfully claiming above that despite making the amps precisely similar, which must surely include the same level of THD (it would be hard to give them the same harmonics spectrum!), the SE amp would still have "higher levels of distortion". xTHD is xTHD, Trevor; all that is different is the spectrum of harmonics. **Incorrect. For and SE amp and a PP amp to deliver a similar level of odd harmonic distortion, the SE amp MUST deliver significantly higher levels of even order distortion. Want me to quote the relevant RDH4 sections (again)? But sure, I include in my definition of "greater fidelity" the quality of distortion. When THD is levelpegged, the SE amp must produce a superior quality result to that of the PP amp. (1) **Not possible. The SE amp will ALWAYS be generating higher levels of even order distortion. PP automatically reduces this effect. ref: RDH4. You can't have it both ways, Trevor! **PP amps allow it. PP amps provide the best of all possible results, with no downsides (apart from a modest increase in complexity). Andre Jute (1) And, as Ruud Broens has already pointed out, odd harmonics are so disturbing that even where the THD of a PP amplifier is lower than that of an otherwise similar SE amp (Trevor's case above), the PP amp is perceived as noisy whereas the SE amp is perceived as blamelessly silent. The proof of the pudding is in the eating. **Indeed. Distortion is bad. Whether it be even or odd order. Given that PP amps reduce even order distortion, they MUST be a better way. -- Trevor Wilson www.rageaudio.com.au |
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#25
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
"Trevor Wilson" wrote in message ... "Andre Jute" wrote in message ups.com... I thought we were having a quiet discussion, Trevor. Now I discover you gloating that you "won" something. **Did I say that? Cite please. I said that PP was the winner. Not me. I am quoting facts. You're the one involved in what you image to be some kind of boxing match. We can safely leave that sort of behaviour to trash like Poopie Stevenson. But I answered all the points in this letter in the one I sent in reply to another. **Ah, the Patrick Turner response. IOW: NO response at all. We should do this again sometime. -- Andre Jute PS Jon, I hope you don't suspect me of rigging the contest. **And yet, you did. YOu assumed that ALL PP amps uise Global NFB and ALL SE(T) amps use none. A rather shabby attmpet to shift the goalposts. If you're comparing apples then you should be using apples, not bricks. I bent over backwards to give Trevor an unfair advantage. Like a gentleman he declined it. **Utter, banal nonsense. Comparisons should be fair and reasonable. IOW: Compare apples with apples, not apples and bricks. Then you might as well stop right now, since it is clear from his history that the person posting as Andre Jute does not argue that way. He never loses because he always cheats. Here's an example of what he thinks about an amp that as far as we know has never been built: http://groups.google.com/group/rec.a...9469d4d1979506 You can also try this link and get some history: http://groups.google.com/groups?q=se...2005&safe=off& It might be interesting for Graham to check some of the details on the names of the people claiming to be friends or business associates of Jute and see if they are sockpuppet's like the other "people" who have come out of the blue to stick up for him. In any case you can't win against a stacked deck, and it's clear from his history that Jute will never answer any question that isn't in the handbook. He just changes the subject or starts 3 attack threads. |
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#26
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SET v. PP, the big fight tonight
On Mon, 19 Dec 2005 08:19:16 GMT, "Ian Iveson"
wrote: There are just three differences between SE and PP, and none are worth fighting about. snipped for bandwidth If you keep posting good sense, you'll just ruin the thread for others. Thanks, as always, Chris Hornbeck "Angels are, dreaming of you" - Sonic Youth |
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#27
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SET v. PP, the big fight tonight
On 18 Dec 2005 22:20:28 -0800, "Andre Jute" wrote:
Chris, darling, WTF do you agree with, Trevor the Efficient or SET the Hedonist or George Lucas the Destroyer? Or did I get it right first time, this is a refined Plainsman's way of expressing contempt for the destructive power of popular culture? Who you callin' re-fined? I' been re-jailed but never been re-fined. Chris Hornbeck "Angels are, dreaming of you" - Sonic Youth |
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#28
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SET v. PP, the big fight tonight
On 19 Dec 2005 02:38:22 -0800, "Andre Jute" wrote:
I thought we were having a quiet discussion, Trevor. Now I discover you gloating that you "won" something. We can safely leave that sort of behaviour to trash like Poopie Stevenson. But I answered all the points in this letter in the one I sent in reply to another. We should do this again sometime. In reality, you were the one who first gloated that he had 'won' - with his manager and seconds holding him up. Actually, of course, you had fallen over your own bootstraps, as usual. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#29
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SET v. PP, the big fight tonight
"Jon Yaeger" wrote in message ... Properly designed SE amps can do nice things in the mid and upper registers, with very efficient low-wattage speakers. But if you like music with lots of bass, well, the single tube SE topology generally doesn't do a good job of controlling a woofer (or its equivalent). I suspect the ganged OTL amps do better on that score, but I haven't auditioned many so far. If you are interested to build a OTL, Bruce Rozenblit has a good design in one of his books. I think there is also a kit of parts available. Lately I've been listening to Cain & Cain single-driver speakers driven by SE and PP amps. Both types can sound very pleasing, but what it drives home is that there are no perfect amplifiers, and no perfect speakers. IMHO, it becomes a contest of bracketing the choices . . . . Funny you should mention Cain and Cain. I went to a demo just a week or so ago, to listen to the Abby (sic) with Fostex drivers. There were several dealers present at the audition, but no-one decided to take the speaker on. I too was disappointed. E.g., SE with good, efficient drivers sounds good over a certain range. But it doesn't deliver the visceral stuff if you like Bach's Toccata & Fugue in D Minor, or Ron Carter. If you use NFB to improve dampening and lower distortion to reasonable levels, it is at great expense of power. Some powerful tubes used for SE are very non-linear (think 6C33) and the music suffers accordingly. How right you are! My only experience with an SET has been with small classical ensemble - Shostakovich String Quartets. I was greatly impressed. I really was sitting in the centre seat row five. However, I am also a jazz fan. The SET amp made a poor job of Ellington at Newport. PP may not have the brilliance of SE in the upper registers, but on balance, it can deliver excellent sound throughout the entire audible spectrum at low distortion & with the other benefits previously & often cited. I'd put a PP amp using good iron (e.g. Eico HF-87 or Acrosound 600) with EL34s or better, operating in Class A against a SE amp any day. Your comments strengthen the view that there is no "ideal" system for every type of music. As Patrick pointed out, if you want a good "all round" amp, an amp for all seasons, then an SS amplifier is probably the right way to go. But, if you want just that little bit more.........:-) I greatly enjoy my 50W PP UL valve amp. I am still thinking hard about building an SET for "small classical" listening sessions though. Regards Iain |
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#30
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SET v. PP, the big fight tonight
"Ian Iveson" wrote in message . .. Andre Jute wrote [snip for brevity] There are just three differences between SE and PP, and none are worth fighting about. First, a SE amp needs a gap in the OPT. In general, this results in lower primary inductance, and therefore curtailed bass, all other things being equal. This is not just a matter of common practice, because if the SE OPT were to equal the inductance of the PP, it would be much bigger, and suffer in terms of primary capacitance, leakage inductance, or both, thus curtailing the top end. Hence the difference here is fundamental. It is possible to use a gapped OPT for PP, so some advantages of the gap are transferable from one topology to the other. One property of the SE OPT is necessarily unique, however: it is biased into the most linear part of the BH curve. Any advantages of zero gap belong to PP alone. Second, the opposition of distortion and power supply products in PP. Assuming both have perfect power supplies, this boils down to a matter of quantity v quality of distortion, and ultimately is a matter of individual perception. ***Here it is, distortion content. SE predominently 2nd order, PP naturally cancels even order harmonics but not odd. I seem to remember the even order harmonics being the reason given for the "monster sound stage" capability of the SE (as written in articles I've read over the years). Building an SE is on my list for future projects if time EVER allows spending time at the bench again! Mark Third, a good PP amp will enter AB operation at the same point that an equally good SE amp begins to clip. All the other stuff is about incidental, rather than fundamental, difference. Without a budget, there can be no sensible argument. cheers, Ian |
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#31
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SET v. PP, the big fight tonight
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#32
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SET v. PP, the big fight tonight
On Mon, 19 Dec 2005 23:56:50 +0100, Lionel
wrote: Dave I have already told you that because of your hearing problems you should stay off the discussions about HiFi... And? Your point? Since you often speak gibberish, we'll just add the above to the list. |
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#33
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SET v. PP, the big fight tonight
dave "deaf" weil wrote :
On Mon, 19 Dec 2005 23:56:50 +0100, Lionel wrote: Dave I have already told you that because of your hearing problems you should stay off the discussions about HiFi... And? Your point? My point ? I let Dédé explains it for me : "Set up two amplifiers exactly the same in all respects except one is PP and the other is SE, with just enough distortion on each amplifier to be perceptible to a refined listener." Dédé is speaking of refined listener, Dave. Refined listener only !!! You have clearly proven that you have a serious hearing loss. A guy who cannot detect a 6 db garbage and lot of distortion in the *critical* frequency range 1 to 3 khz is everything you want but surely *not* a refined listener. Since you often speak gibberish, we'll just add the above to the list. This will not change anything to your disability. If you was honest with yourself you would try to answer to this simple question : when you go to the rock concert why are you looking for a place in the first rows ? The answer is simple Dave, because you have serious hearing problem. Not a big issue after all, thanks to Dédé we have seen even some great musician suffer this kind of problem. Note that "at least" they aren't trying to write speaker review... ;-) -- "Nobody seemes to have actaully read what i wrote. But what's new around here?" Dave Weil, Sun, 05 Oct 2003 00:57:15 |
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#34
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
On 19 Dec 2005 15:30:31 -0800, "Andre Jute" wrote:
dave weil wrote: On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson" wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Can you say, "Strawman"? To be fair, Dave, he talks about "greater fidelity", thought the answer is still the same. Here is an experiment: Set up two amplifiers exactly the same in all respects except one is PP and the other is SE, with just enough distortion on each amplifier to be perceptible to a refined listener. Spin a disc. If the two amps are *in fact* the same in all respects, i.e the same tubes at the same operating point, then the SE amp will have the same level of odd harmonics as the PP amp - but *much* more 2nd harmonic than the PP, which of course cancels the even harmonics. To make the distortion levels 'just perceptible' in each case means that the SE amp has much *less* basic distortion than the PP amp - which is of course a completely unrealistic scenario. Now the SE amp will give you the warm glow that the same music originally gave you in the concert hall. No, it will give you a warm glow that *never existed* in the concert hall - it washes whiter than white. The PP amp will have that disturbing edge of odd harmonics. Reduce the level of distortion a little to below perception. Now the SE amp still sounds great and you can live with for a long time. But the PP amp is not so comfortable after a disc or two; it demands attention with a certain edgy quality. If the distortion is below perception in each case, then the amps will sound identical. I believe our colonial cousins would insert a 'duuhh' around here somewhere....... Which offers a window on the concert hall? Which is the amp you want to live with? In the second case, they are both just fine, but the SE amp will have cost much more, so you have less money to spend on speakers....... -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#35
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
Stewart Pinkerton wrote: On 19 Dec 2005 15:30:31 -0800, "Andre Jute" wrote: dave weil wrote: On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson" wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Can you say, "Strawman"? To be fair, Dave, he talks about "greater fidelity", thought the answer is still the same. Here is an experiment: Set up two amplifiers exactly the same in all respects except one is PP and the other is SE, with just enough distortion on each amplifier to be perceptible to a refined listener. Spin a disc. If the two amps are *in fact* the same in all respects, i.e the same tubes at the same operating point, then the SE amp will have the same level of odd harmonics as the PP amp - but *much* more 2nd harmonic than the PP, which of course cancels the even harmonics. To make the distortion levels 'just perceptible' in each case means that the SE amp has much *less* basic distortion than the PP amp - which is of course a completely unrealistic scenario. Exactly! That is why a silent SE amp, such as I build, sounds so much better than anything else. Life isn't fair, Stewart. That's just a normative case they teach in engineering departments so the students don't run away to become plumbers and earn real money and retire to Spain (horrid thought) at 35. Now the SE amp will give you the warm glow that the same music originally gave you in the concert hall. No, it will give you a warm glow that *never existed* in the concert hall - it washes whiter than white. Hey, persil is good too. I'm outa advertising. The housewife isn't stupid, she's your wife. The audiophile, at least the one with the sense to buy tubes, isn't stupid, he's your paymaster. The PP amp will have that disturbing edge of odd harmonics. Reduce the level of distortion a little to below perception. Now the SE amp still sounds great and you can live with for a long time. But the PP amp is not so comfortable after a disc or two; it demands attention with a certain edgy quality. If the distortion is below perception in each case, then the amps will sound identical. In your normative case, sure. In real life the SE amp will be ZNFB and the PP amp will have NFB. After 14 hours (not a random number but the average number of hours an amp is on in my study every day) the SE amp will still please but the NFB will not just be audible, it will visible and threatening. This isn't about numbers but about the discrimination of taste and experience. I believe our colonial cousins would insert a 'duuhh' around here somewhere....... Proud to be an Australian. Which offers a window on the concert hall? Which is the amp you want to live with? In the second case, they are both just fine, but the SE amp will have cost much more, so you have less money to spend on speakers....... Says a guy who bought a Krell! What's more, the discussion above proceeded from the standpoint that the audiophile in question already owns Quad ESL of some kind and Tannoy Royal Westminsters too. He's not spending on speakers any more. I didn't mention that as it was too obvious. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#36
Posted to rec.audio.tubes
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SET v. PP, the big fight tonight
"Jon Yaeger" wrote in message ... in article , Iain Churches at wrote on 12/20/05 5:46 AM: pardon the truncation If you are interested to build a OTL, Bruce Rozenblit has a good design in one of his books. I think there is also a kit of parts available. *** Actually, I've laid out one of his EL509 OTL amps on one of my chassis. I had ordered two custom power toroids from Plitron. Now I just have to find the time to wire it all up . . . . Hi Jon. That's good news- Please kep us informed. It is worthy of a new thread. The SET amp made a poor job of Ellington at Newport. *** Do you have favorite selections that you use as a frame of reference? I find that piano and female vocalists are the most helpful. Piano gives a good idea of transient response, attack, and sibilance. Examples: Bill Evans, Michel Petruciani. Verve and ECM generally have good recordings. Do you concur? Yes indeed. I use piano and female often for evaluation. I have some very good material by Judie Tzuke (voice and piano) and some first class recordings of Oscar Peterson (or Peter Oscarson, as my wife calls him) solo piano and trio. When I go to a new recording venue, I try to listen to music of the genre which we shall be recording to get to know the sound of the control room. But assessment of the venue itself is a separate problem:-) When listening to people's systems, I always take with me something appropriate for that system. Yesterday I was invited to listen a VAC 80W KT88 amp which I had recently cornverted to triode, driving a pair of PHY full range open baffle speakers. Quite an interesting set up. The owner had a huge penthouse apartment. The listening area was probably about 80 sq metres. Lined on three sides with CDs and vinyl, many many thousand in number and record catalogues of most of the major companies. I picked up the Penguin CD Guide. The chap said: "I have most of those" He is a "serious" audiophile. I greatly enjoy my 50W PP UL valve amp. I am still thinking hard about building an SET for "small classical" listening sessions though. *** In what direction are you headed? I've got a 6C33 and some Lundahl iron, but I'm concerned that the 6C33 is kind of crappy for audio. I am still at the thinking stage. This is a subject which I would like to discuss with Patrick, Andre and several others, who have a lot more practical experience in SET than I. However, I think a parallel solution might be best, as I want to drive a pair of splendid old Kef K1's which are not particularly sensitive. This thread is now pretty long, and as I would like to turn a corner, and chat about jazz with you Jon, so I will start a new one. Best regards Iain |
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#37
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
"Trevor Wilson" wrote in
message "Andre Jute" wrote in message oups.com... True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. One might try to compare SET and PP by comparing two amplifiers, one a SET and the other a PP amp built up by running two SETs identical to the first, in PP. Now let's compare these two amps that differ only in that one is PP and the other is SET. Let's further stipulate that listening levels will be kept low, so that any power advantage of the PP amp is nullified. We find that the SET puts out its usual mixture of even and odd-order distortion. The PP setup will internally cancel out the even order distortion, leaving only the same odd order distortion that the SET produced. From the stand point of production of odd order distortion, the two amps are identical. The SET differs in that it also produces even order distortion. The SET amplifier therefore provides no meaningful advantage from the standpoint of reduction of odd-order distortion. It simply produces more even-order distortion. It is well known that amplifier nonlinearity whether odd or even order does not produce only harmonic distortion. Amplifier nonlinearity produces IM distortion. Even order nonlinearity is an especially effective means for producing intermodulation products. IM distortion is almost guaranteed to be non-harmonic and therefore very irritating to listen to. In addition to producing less over-all distortion, the PP amplifier will also produce less IM distortion than the SET amplifier. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? The universe of SET hysteria, of course! ;-) |
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#38
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
"Andre Jute" wrote in message oups.com... Stewart Pinkerton wrote: On 19 Dec 2005 15:30:31 -0800, "Andre Jute" wrote: dave weil wrote: On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson" wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Can you say, "Strawman"? To be fair, Dave, he talks about "greater fidelity", thought the answer is still the same. Here is an experiment: Set up two amplifiers exactly the same in all respects except one is PP and the other is SE, with just enough distortion on each amplifier to be perceptible to a refined listener. Spin a disc. If the two amps are *in fact* the same in all respects, i.e the same tubes at the same operating point, then the SE amp will have the same level of odd harmonics as the PP amp - but *much* more 2nd harmonic than the PP, which of course cancels the even harmonics. To make the distortion levels 'just perceptible' in each case means that the SE amp has much *less* basic distortion than the PP amp - which is of course a completely unrealistic scenario. Exactly! That is why a silent SE amp, such as I build, sounds so much better than anything else. The only time an SET sounds good is when it's silent. :-) It's when you turn them on that they suck. |
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#39
Posted to rec.audio.tubes,rec.audio.opinion
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SET v. PP, the big fight tonight
On 21 Dec 2005 00:50:40 -0800, "Andre Jute" wrote:
Stewart Pinkerton wrote: On 19 Dec 2005 15:30:31 -0800, "Andre Jute" wrote: dave weil wrote: On Mon, 19 Dec 2005 21:28:36 GMT, "Trevor Wilson" wrote: True. A great advantage, much more pleasant than the odd harmonics of PP even when the latter is at a much lower absolute level. **Huh? In which universe do you imagine that higher levels of distortion will lead to greater fidelity? Where did he talk about "fidelity"? Can you say, "Strawman"? To be fair, Dave, he talks about "greater fidelity", thought the answer is still the same. Here is an experiment: Set up two amplifiers exactly the same in all respects except one is PP and the other is SE, with just enough distortion on each amplifier to be perceptible to a refined listener. Spin a disc. If the two amps are *in fact* the same in all respects, i.e the same tubes at the same operating point, then the SE amp will have the same level of odd harmonics as the PP amp - but *much* more 2nd harmonic than the PP, which of course cancels the even harmonics. To make the distortion levels 'just perceptible' in each case means that the SE amp has much *less* basic distortion than the PP amp - which is of course a completely unrealistic scenario. Exactly! That is why a silent SE amp, such as I build, sounds so much better than anything else. Except that you don't, and they don't. Life isn't fair, Stewart. That's just a normative case they teach in engineering departments so the students don't run away to become plumbers and earn real money and retire to Spain (horrid thought) at 35. Sure life's fair - it's *people* who try to make it unfair. Now the SE amp will give you the warm glow that the same music originally gave you in the concert hall. No, it will give you a warm glow that *never existed* in the concert hall - it washes whiter than white. Hey, persil is good too. I'm outa advertising. The housewife isn't stupid, she's your wife. The audiophile, at least the one with the sense to buy tubes, isn't stupid, he's your paymaster. Nope, he's spent far too much money on tubes to afford to hire anyone. The PP amp will have that disturbing edge of odd harmonics. Reduce the level of distortion a little to below perception. Now the SE amp still sounds great and you can live with for a long time. But the PP amp is not so comfortable after a disc or two; it demands attention with a certain edgy quality. If the distortion is below perception in each case, then the amps will sound identical. In your normative case, sure. In real life the SE amp will be ZNFB and the PP amp will have NFB. After 14 hours (not a random number but the average number of hours an amp is on in my study every day) the SE amp will still please but the NFB will not just be audible, it will visible and threatening. This isn't about numbers but about the discrimination of taste and experience. Actually, in your case it's about bull****. A clean amp is a clean amp is a clean amp. It is always informative when you are ruminating happily about the wonders of SET - and suddenly realise that the other amp is the one that's actually connected! I believe our colonial cousins would insert a 'duuhh' around here somewhere....... Proud to be an Australian. I thought you were a Sarth Efrikaan? Which offers a window on the concert hall? Which is the amp you want to live with? In the second case, they are both just fine, but the SE amp will have cost much more, so you have less money to spend on speakers....... Says a guy who bought a Krell! Indeed, and for less then a grand, and it drives everything from Lowthers to Apogees with equal aplomb - and sound just like its input signal, as it should. What's more, the discussion above proceeded from the standpoint that the audiophile in question already owns Quad ESL of some kind and Tannoy Royal Westminsters too. He's not spending on speakers any more. I didn't mention that as it was too obvious. Not an unreasonable choice for the well-heeled audiophile, just needs a decent 60-watter in each case. Fortunately, many excellent amps of this description are currently available. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#40
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SET v. PP, the big fight tonight
"Stewart Pinkerton" wrote in message ... On 21 Dec 2005 00:50:40 -0800, "Andre Jute" wrote: Actually, in your case it's about bull****. A clean amp is a clean amp is a clean amp. It is always informative when you are ruminating happily about the wonders of SET - and suddenly realise that the other amp is the one that's actually connected! **Funny you mention that, Stewart. A couple of years ago, I was asked to service two, stereo, 3 Watt (PP) valve amps. Unfortunately, apart from several buggered valves, all the electros, many of the resistors and most of the old plastic capacitors also required replacement, it had three (out of four) faulty output transformers. This would have put the price into the ridiculous area. Then, I had an idea. I put a pair of small power OP amps in each amp. I put a LF and HF filter in front of each OP amp and ran the whole shebang off the filament supplies. I left the valves in place and told the client that I had fixed his amp. If was in any way unhappy with the result, I would refund his money, in full. The cost, of course, was significantly lower than replacing all the faulty stuff. After he'd used it for a week, he reported that his amps had never sounded so good. -- Trevor Wilson www.rageaudio.com.au |
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