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Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
In article , Trevor Wilson wrote:
"mick" wrote in message .. . You can produce two signals with identical THD%. **Yep. One will have very audible distortion and the other won't. **Yep. It depends on the relative strengths of the harmonics. **And the TOTAL level of those harmonics. Less than around 0.1% is inaudible, regardless of the harmonic structure. That is why I cited 0.1% as being a reasonable indicator of 'high fidelity'. Out of curiosity I have been looking for tables of "just detectable" distortion levels versus harmonic number. However I have not found one yet. There are some clues as well as the 0.1% figure above (well, maybe clues if you take magazine reviews with just a small a pinch of salt). From a Stereophile review of a Cary CAD-300SEI valve/tube amp (http://www.stereophile.com/amplifica.../index5.html): "It's a common mistake to consider a single THD figure an indicator of distortion audibility. The THD+N figures in the previous graph sum all harmonics and noise for a single figure and ignore which harmonics are present and in what ratios. As you can demonstrate for yourself with the second Stereophile Test CD, 0.3% of seventh-harmonic distortion is more annoying than 10% of second-harmonic distortion. Generally, lower-order harmonics are less audible, as are even-order harmonics (second, fourth, sixth). The most benign harmonic distortion is thus second-harmonic." This appears to claim 0.3% of seventh is "annoying". The reviewer then goes on to write (with an editorial comment): "... Because the distortion is primarily low-order, the 300SEI can get away with having several-percent THD. [While the distortion will be audible, it will be relatively musically consonant, which is not the same thing as being inaudible.Ed.] " Maybe I will have to write a test CD or two and see what I can hear under informal test conditions (especially since I do not know my loudspeakers' distortion spec. figures). I assume distortion levels are quoted as voltage ratios (even though what may matter to the ear could be different)? -- John Phillips |
Valve amp (preferably DIY) to drive apair of Wharfedale DiamondII's
Stewart Pinkerton wrote:
I think you miss the point. We older folks who have had extensive experience of both valve and SS amps over the years, are perfectly well aware of what some people like abiout valve amps. There is no 'mystery' here, simply a collection of very well-known *euphonic* artifacts which are most noticeable in single-ended designs, and hardly exist at all in some high-powered and very high quality designs such as the ARC VT100. Some of us prefer SS amps, or at least sonically transparent amps, and we resent valvies telling us that SS amps produce 'cold, harsh' sound, when what is *really* happening is that good SS amps reproduce their inputs faithfully, while valve amps do not, but *add* artifacts which some people prefer. Hence the kind of comments which you quite rightly ascribe to us above. In the real world, there *is* no audible distortion in good modern amps (SS or valve), they *are* to all intents perfect, and here's the clincher, they *do* all sound the same. Fair point, and taken. As you know I started this little run of posts, attempting to give my view as to why people were not prepared to accept Ian's description of the situation, not to try and attach correctness to either side of the "discussion". -- Nick |
Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
In article , Nick Gorham
wrote: Ian Molton wrote: Why cant you accept that valve amps (non transparent ones) simply distort in a way you like, and (good) SS (or valve) amps do not distort audibly. Because, whilst I don't think anyone is claming that valve amps produce less measurable alteration of the signal than solid state ones, I think everyone who is trying to make the same point, is saying that it seems to them that the valve amp appears to reproduce music in a more accurate fashion, not measurable accuracy, but percieved accuracy. And because of the perceived increase in accuracy, I think that people find the use of the word distortion problematic. It is hard to use a term that you have attached negative connatations to, to describe a effect that they see as positive. Yes. The problem, though, is that 'accuracy' has a fairly specific meaning to the designer of an amplifier in that it already has a technical definition in terms of the measureable waveshapes at the i/p and the o/p of the amplifier being the same except for a scaling factor and/or perhaps the (linear) alterations in relative scale/phase of some frequency components. Hence the above runs into trouble when trying to communicate what you mean when it uses 'accuracy' *unless* you make fairly clear -as you *do* above - to indicate that you don't mean the defn I have just outlined. Hence it is advantageous to make clear this difference in definition of the term employed. However when it comes to engineers/designers or users obtaining 'better' (deliberately vague) amps, some definition that can be used to systematically guide and test design is desirable. Hence we then have to wonder what 'accurate' or 'better' might mean in engineering terms. Without this, progress becomes almost random. Since people may also be using 'better' or 'accurate' to mean *different* things development or improvement becomes severely impeded, and people end up arguing about (literally) meaning-free points, often not noticing that they are using the same words, but not the same language. Step back from this for a minute and think about it, there have been a steady procession of posters saying almost the same thing about why they like valve amps, and what they percieve the difference in sound to be. There seems to be a high correlation between their description of the sound, and what it is that they feel is lacking in solid state amplification. This to me is showing that there may well be something real at work here, something that should deserve closer study. I agree. (Also w.r.t to vinyl as well!) Indeed, one of the points of the two HFN articles I wrote last year was to show that when we take the nonlinear properties of human hearing physiology into account, then we may find that some alterations of the sound might (possible) act as cues or aids to perception, and/or some forms of distortion were essentially benign at some levels. However it becomes impossible to get beyond such a general hypothesis if examination of this area can't establish a sensible method/language for its consideration.... Without suitably defined terms, how do we communicate or think about the matter beyond simple sensation reactions? While on the "other" side, there is a monotone of comments along the lines of "nothing to see here, move on". No audible distortion, For all intents perfect. All sound the same, etc... Well, my personal view is that if we *can* identify 'alterations' that aid perception then be can then exploit them without having to rely upon an amplifier to do so on an almost 'accidental' basis as a byproduct of some unspecifiable process. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
Valve amp (preferably DIY) to drive apair of Wharfedale Diamond
There seems to be a high correlation between their description of the
sound, and what it is that they feel is lacking in solid state amplification. That's true - people have ears. This to me is showing that there may well be something real at work here, something that should deserve closer study. There is something real here, but it's pointless discussing it with deliberate unbelievers. Of course I read your posts, Nick, but I also filter out a good number of other posts. As you know, you'll find plenty of 'further study' over on the asylum and DIY Audio, and discussion of a healthy kind about the projects they are building and finer points of the theory. An hour spent with the soldering iron out making valves glow is worth about 6 months of futile debate. It's interesting to talk to people like you on the ng, but the threads just don't go anywhere because the noise level is like talking in a Rugby club at 11 o'clock on Saturday evening after a home win. Andy === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
Valve amp (preferably DIY) to drive apair of Wharfedale DiamondII's
Nick Gorham wrote:
Ian Molton wrote: If you took a moment of your time to noitice that I had snipped all the text that didn't relate directly to my reply, you may even get to read it in the first place. Thats a matter of opinion... I try to assume others may be reading the post, and may not want to take the trouble of checking the previous ones, so try and include enough to make the post self explanitory, without altering the point or content of said post. Why make it harder for those of us who arent lazy-arses, and easier on those who are? any competant newsreader can show threaded views. The light from the sun is closest to true white, being composed of nominally even levels of the full spectrum of visible light. Yes, I said that, why are you repeating what I said in such a way to make it sound as if you are correcting me by just repeating? Actually you didnt mention the 'nominally even' bit... there exists a real definition for white light. there is no such definition for the synthesised 'white' light produced in CRTs. no two are alike. Yes, I said that, why are you repeating what I said in such a way to make it sound as if you are correcting me by just repeating? Is there an echo in here? and no, you said no such thing. show me where you said there is a definition for true white light. In terms of perception, yes, they are both 'white' (to me). In terms of accuracy, sunlight is way closer. That was my exact point, in terms of your perception (and AFAIK everyone else's) they are the same, Actually, in many cases the light from my monitor differs visibly, and I dont just mean in intensity. On a bright sunny day, both UV and IR make themselves known. so only a pedant would not describe the light from a CRT as white, Only a fool would not call it white, indeed, in normal conversation. However in terms of a definition, it is a poor substitute for the real thing. and the accuracy of that white-ness can be measured and described in terms of a colour temperature, which only has real meaning for a hot body emmiting a continuious spectra. So the accuracy of the whitenes from a CRT can be measured and discussed, Under certain circmstances. Besides, the spectra emitted by the phosphors will overlap to some extent, despite peaking in red, green, and blue. whereas its not actually white at all. Hence the example of "percieved accuracy". No, the perception of white is a trick based on the fact that our eyes only see in three primary spectral bands. Not all people perceive colour the same way, either. |
Valve amp (preferably DIY) to drive apair of Wharfedale Diamond
Andy Evans wrote:
There is something real here, but it's pointless discussing it with deliberate unbelievers. I wonder how many of you nutters are also devoutly religious? How many of you are creationists? |
Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
In article , Keith G wrote:
Other than 'signal breakup' when the volume's wicked up too hard in certain circumstamces, what TF does this 'distortion' actually sound like?? What should I be looking for?? Perhaps if I knew what it was I could develop a loathing for it also.....??? :-) I annoy my musician friends by liking recordings which are not up to their high technical music performance standards. I refuse to learn to dislike something musically superb for its trivial technical imperfections. In music reviews I find the Penguin Guide and the Radio 3 reviewing crews to be like my musician friends - they will substantially mark down a performance for technical performance imperfections which I find unimportant (e.g. missing repeats in some circumstances). Thankfully the Gramaphone's and the Diapason's reviewers are more aligned with my own musical appreciation. Of course the Penguin/R3 reviewers and my musician friends are right too in striving for the very best musical performances in a technical sense. So, you should stick to your own principles in audio appreciation. I will certainly continue to be interested in my type of imperfect but good music and interested in the technical aspects of the best possible audio reproduction. (Now, why do I also know that I'm not going to get an answer to this that doesn't sound like it's coming from a raving looney?) Oh, well. -- John Phillips |
Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
Expect thats the new bottles giving out the smell, had the same thing happen here when I installed 8 new KT88's..the stink was 'orrible but it went away after about an hour. Funny that, because it's the first time I had quite that strong smell from new power valves...probably a bit of burnt bean sauce and rice wine after the factory lunch break :-) ......If they have one that is! Mike Smelly amps after turn on indicate the tubes have not even been tested properly. I hope they last. Chinese KT88 copies had a reputation for having a 40% failure rate over 12 mths. The problem is that chinese amps might look nice, even sound nice, but the detailed examination of the circuit and output transformer quality often leaves a lot to be desired. They seem to be improving slowly. Patrick Turner. |
Valve amp (preferably DIY) to drive apair of Wharfedale Diamond II's
"Patrick Turner" wrote in message ... Expect thats the new bottles giving out the smell, had the same thing happen here when I installed 8 new KT88's..the stink was 'orrible but it went away after about an hour. Funny that, because it's the first time I had quite that strong smell from new power valves...probably a bit of burnt bean sauce and rice wine after the factory lunch break :-) ......If they have one that is! Mike Smelly amps after turn on indicate the tubes have not even been tested properly. I hope they last. Chinese KT88 copies had a reputation for having a 40% failure rate over 12 mths. Dunno Patrick I went back to Svetlana's 6550C's again because I lost at least 50% of the dynamics with the '88's but gained some (psudeo?) 'air', IMO not worth the trade. Tried KT90's which went far too far in the other direction :-) The problem is that chinese amps might look nice, even sound nice, but the detailed examination of the circuit and output transformer quality often leaves a lot to be desired. They seem to be improving slowly. Get over there, you'd make a shed load of cash designing machines to make wide band width OPT for future audiophile amplifiers Patrick Turner. |
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