Talk:Valve audio amplifier/Archive 1

message: Light current editted out a comment related to "monotonically decreasing harmonic distortion only, which may be one mechanism behind the enthusiasm for this type of amplifier.... high levels of even order harmoic (notably 2nd order) distortion, even though puristically "wrong", is actually adding musical richness (ie a perfectly tuned chord)... Another problem is the great difficulty in correlating measured performance with the quality or even accuracy of sound
I totally agree with Lightcurrent that as originally written this sounded speculative, however it is imho essential to say something about the reasons why such antiquated technology is preferred .. that those how audition it recognise a striking sonic differen / improvement .. the problem being that while enthusiasts massively agree it does sound different / better, there is unfortunately no generally agreed opinion about which of many mechanisms / effects is the most important. There is no objective relality to refer to here ; one of the "facts" is that the way the human ear/brain COMBINATION "hears" sound is much more subtle than simple measurements of frequency / phase / distortion however as measured, even with the cutting edge test equipment : it is one thing to objectively measure the distortion spectrums of two different amplifiers with similar levels of distortion but different spectrums, with great precision. Explaining which one sounds better, and saying why, sadly is not so objective. You may as well ask the worlds priests which is the one true god
Its therefore my view that this is one of those few cases where weasel words actually are needed, albeit we can state as a fact that the religious nature of opinions is a characteristic of interest in audiphile audio ampifiers these days
What IS objectively known is that high distortion on one harmonic tends to mask lower distortion on higher harmonics, even order harmionics sound "nice" (chords), odd order sound bad, and aharmonic products sound awful (discordant).Complex distortion products  due to complex circuit desgn, NFB and/or imperfect (ie real world) components also sounds bad.
ignoring the use of tubes rather than Mosfets as DEVICES (thats a whole other religious debate), A central factor in the arguments in favour of audiophile amplifier designs is simplicity / low component count and limited / no feedback, which results in higher distortion levels, but simpler and predominantly harmonic distortion spectrums
I think we have to say SOMETHINg about this, while recognising that there is no one right view about the absolute order of importance of all these issues (indeed audiophile amps  are, due to thier simplicity and low parts count, exceptionally ammenable to holistic design / tuning.
tubenutdave 14:42, 1 January 2007 (UTC)
replies: text: Say something but please dont speculate. provide quotations or refs!--Light current 16:55, 1 January 2007 (UTC)
thread_title: Why SE amps (and more generally tube amps) are considered (by some) to be superior

message: Im quite prepared to believe that tube and transistor amps sound different althought I have not heard a Hi Fi tube amp for a long time.
Actually the first amp I owned was a mono tube amp with two ECC83s and 2 KTT66s as the output pair (if i remember correctly). The power o/p was 8W! I dont remember how it sounded and the sound was probably limited by the crap source and speakers I was using.
Im also quite prepared to believe that some people prefer the sound of tube amps cf transistor ones. What Im not convinced of is that tube amps are more accurate to the original sound.
I suppose it all comes down to: choose which type of distortion you prefer (or can live with), then buy an amp that gives you it! This maxim of course applies to all other uses of electronic amplifiers.
*To say that tube amps with NFB are superior to transistor amps with properly designed NFB is probably not correct.
*To say that triode tube amps without NFB are superior to very high gain transistor amps with no NFB at all is probably correct.
I dont think anyone would disagree with the fact that NFB generally gives a more accurate SS response than open loop, and if well designed can give reasonable transient responses also.
It may be possible to get tubes with reasonably linear transconductance these days, and this may indeed be more stable than the Beta of a transistor (which is why transistor cct topology should not rely upon a transistors beta!)
But this isnt saying much, as transistors are not capable of linear operation without some forms of NFB.
I beleive well designed NFB amps (both tube and transistor) can give very good performance.
It may also be possible to design a tube amp that is as clean as a transistor one except that the o/p transformer design may be a bit of a problem (unless toroidal cores and bifilar windings were used).
I also believe it is more difficult to design NFB tube amps because of the o/p transformer.--Light current 03:37, 3 January 2007 (UTC)
thread_title:  Reply to Tubenut 

message: Your previous edits contained a number of errors in formatting, spelling etc. I shall continue to correct these along with any other mistakes I see. Also, as WP is all about providing referenced, well written material in the articles, it is actually possible for editors ignorant in the finer points but educated in general electronics (like me) to contribute. 
In fact, standing back from a subject can be a positive asset in improving articles as Im sure a number of other editors would agree. 
Im not saying you dont know a lot about tube amps (and a lot more than I do), but it is not our purpose here to convert everyone into Tube amp worshippers (or transistor amp worshippers), but merely to describe valve audio amplifiers without expressing any point of view or bias whatsoever. WP:POV
Neither is it acceptable to make 'non common sense' statements without references.  You should write in an encyclopedic manner, using the Wiki formatting rules. See WP:MOS.
If you adhere to these guidelines I have no problem with you continuing to edit these (or any other) pages.
Also, there is no need to assume that any editor (including me) is against you personally unless you see evidence of the fact. Everyone should assume good faith.WP:AGF
Im trying to improve the article. Let us not engage in personal attacks WP:NPA, but improve the articles together. 
Please take some time to read these guidelines to avoid falling into some of the traps that new editors are prone to.  8-)--Light current 02:48, 3 January 2007 (UTC)
replies: text: I have tried to rewrite some of this in a more objective style. Feel free to revise the wording to make it even more objective if you can, however please note that while most informed commentators in thise field would agree aboit the mechanisms that exist (and there are many, not only those hinted at so far !) there is NOT any consensous as to which effects are the most significant, which approaches work best, and indeed as always in engineering compromises which effects are the most salient vary from case to case, and all have to be balanced as a compromise, to succeed you cannot just pick one and ignore the otherstubenutdave 17:04, 1 January 2007 (UTC)
thread_title:  Second reply to Tubenut 

message: Also desirable imho are additional pictures and descriptive text of notable/representative tube maps(Quad II, Dynaco MkIII, Macintosh 275MC, Audio Research, Audio Note Ongaku etc) should imho also be added if someone has such they have the copyrights for. tubenutdave 22:15, 31 December 2006 (UTC)
replies: text: No I got these from some other WP articles. If you click on the pics youll see the licensing statement. (so copyright is covered) and you are free to include them in any article--Light current 02:55, 3 January 2007 (UTC)
thread_title: more pictures / iconic commercial products needed