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In Reply to: Your post seems rather brusque and condescending... posted by Wellfed on January 23, 2005 at 00:58:34:
Hi,> Do you know djn and what his tastes are?
No, therefor I stated my preferences AND qualified my statements.
> "Best avoid, if your tastes in sound run like mine."
> How would one know what your tastes are so as to apply
> any relevance to your statement.Given that I have published quite a few reviews (in TNT Audio and at ETM) as well as loads of other writings that is easy enough.
> What does your phrase "they tend to generalise too much" mean?
Exactly that. In real music there is (unless computer genrated) an unavoidable minute variation from note to note, phrase to phrase and so on. I find that in subjective terms Amplifiers using large amounts of negative feedback tend to obscure these variations more than amplifiers with no loop feedback.
> As for my tastes, Atma-Sphere M-60's, driving Köchel K-300 horns,
> using an Audio Synthesis DAX Discrete for a source, provide me
> with ecstasy beyond words. I have heard you mildly diss each of
> these products, or at least their progenitor, at one time.The Koechel Horns, you should be aware, are Speakers I quite like.
I listed the M60 as my second favourite OTL Amp of those I heard (which does not say I don't prefer something else though).
The various DAX Dac's tend to also come up occasionally in my writings as worthy of note, however I feel that a really well implemented Non-Oversampling DAC offers sound more to my liking.
> What does this mean? People have different tastes?
Exactly. Recording & Reporduction is invariably drastically flawed. In order to get the experience we want from listening to recordings we need to arrange our systems such that they avoid emphasising the areas where we as individuals tend to react to the difference between recorded and real music while emphasising or at least excelling at what are the core areas of music that us spell "reality".
> We all value our own opinions, but your outburst is more than
> a little over the top IME.OUTBURST?
Someone asks "what is a good OTL Design to build".
I list my experiences with OTL Designs I have heard and simply note that contrary to the Hype some people generate OTL Amplifiers are not perfect or the end to it all.
And that is an OUTBURST? Pulleeese.
> Having said all that I still enjoy reading your
> thoughts and would love the opportunity to meet
> and listen to your system some day.If you find yourself in London, you are welcome to drop in.
> One last thing, I don't think Atma-Sphere amps require NFB.
The commercially sold ones have it and quite a good dollop too. If you remove the NFB, the output impedance gets very high. High enough that you actually need to design a speaker especially to co-operate with that high output impedance (which is not per se a bad thing, on the contrary, I have been advocating "current drive" to speakers for a long time).
And of course the distortion goes up and as in OTL's in generally the distortion open loop must be fairly high and is generally composed of quite a few high order components, which may or may not be audible as sonic problems.
As with all engineering, everything is about tradeoffs. Going OTL means you trade off some things for the ability to say "there is no Output transformer coloring my sound". I believe for somone who wonders if he should invest into such a device it is important to be aware of the tradeoffs.
Ciao T
Follow Ups:
The M-60s have about 0.5db of negative feedback if I recall correctly (hardly a huge amount). The MA-1 and MA-2 have always had ZERO negative feedback. The newest ver.3 of the MA-1 and MA-2 now includes switchable negative feedback for 0, 1 or 2db.
Hi,> The M-60s have about 0.5db of negative feedback if I recall
> correctly (hardly a huge amount).The current M60 lists as follows:
Output Impedance: ~4.1 Ohms
Feedback: 1 dbIt seesm the feedback has been reduced from earlier versions (good idea), if at the cost of an output impedance a bit on the high side for the real world.
> The MA-1 and MA-2 have always had ZERO negative feedback.
> The newest ver.3 of the MA-1 and MA-2 now includes
> switchable negative feedback for 0, 1 or 2db.So NFB was added.
I agree however that these leves are much less than what memory told me, especially on the subject of the M60.
Still, it would seem that M60 has around 5 Ohm Output Impedance without NFB which makes using it with conventional speakers a little difficult. The 6db or so NFB I remembered would have brought this down to a more usefull 2.5 Ohm, now more less on parity with a typhical SE Amp on the 8 Ohm Tap.
However, these fairly low levels of NFB (as also found in the Graaf) underscore why I listed them among my favourites, strictly on sound, as I did not dive too deeply into their designs. And why the SEPP OTL's I have heards all where much worse.
It's probably worthwhile for people considering OTL's to read carefully the various specifications found on AtmaSphere's website.
So my recommendation to djn remains as written, try a M60 Clone, there is enough info out there to do that.
Ciao T
BTW, here a page with an Amp one might call AS M60 Inspired....The Guy who build it omited NFB and clocked 10 Ohm Output Impedance, suggesting that really some 12db of NFB would be needed to get the output impedance down to tolerable levels for conventional speakers, or using 4 X the number of output Valves.
Ciao T
Your posting, read in the wee hours especially, appeared quite condescending, almost as if you believed yourself the sole arbiter of good taste and sensibility. Re-reading your post in the light of day, along with your further responses in this thread, temper that impression considerably. Again, pardon my outburst.I am still not quite tracking your thoughts on 'generalisation'. Any additional insight is appreciated. You seem to be saying OTL's using NFB severely limit resolution.
Hi,> I am still not quite tracking your thoughts on 'generalisation'.
With that I mean a diminished perception of the differences between the individual notes playing style. In other words, each note or phrase sounds more like the others except for diferences in pitch and general loudness.
> You seem to be saying OTL's using NFB severely limit resolution.
No, I am saying that all amplifiers I have heard, designed and build which use large amounts of NFB around certain types of fairly non-linear structures (among which arguably fature OTL's) seem to lead to an effect that subjectively seems to rob music of some of it's life, of some of the things that for me demark differences between "real vs. memorex".
This even appears to apply to certain forms of digital feedback (Delta Sigma Noiseshaping for example).
Ciao T
You rightly emphasize two things that everyone probably knows, but which are often overlooked, I think. (1) Excellence in hi-fi does not yield a single linear ordering (a single ranking, best to worst), because what is desirable in sound reproduction is not given a priori - different people will value different things. BUT this does not mean that it is all subjective, that there are not objectively or intersubjectively valid rankings etc; it merely means that there are many orderings (which may criss-cross in various ways). (2) The bottom line for engineering in any domain is, does it work? Does it do what we want (at acceptable cost, reliably etc.)? Our hi-fi world is infested with component or design-fetishism - this type of amp, this type of wire is absolutely the best. Fetishism, by definition, is the belief that certain properties are contained in some object which are not really contained in the object, but only in certain contexts in which the object occurs. One falls prey to it precisely when one is ignorant of the way in which the context works - eg, of the ways in which circuits actually work. It is easier to pick out some element and imagine that the magic is all contained in that. So for an amateur like me, all I can do is to be very sceptical of what anyone who is not a real engineeer says about hi-fi, except, at most, what something sounds like.
Hi,> (1) Excellence in hi-fi does not yield a single
> linear ordering (a single ranking, best to worst),
> because what is desirable in sound reproduction is
> not given a priori - different people will value
> different things.Absolutely. Which is one of the key reasons why so far no formal measuremenst of quality have been devised that show any significant correlation with percieved "good sound".
> (2) The bottom line for engineering in any domain
> is, does it work?How do we define "it does work"?
Does it work if it fulfills the German DIN 45500 Standard?
> Does it do what we want (at acceptable cost, reliably etc.)?
How do you define this then, unless on an individual, subjective basis?
> Our hi-fi world is infested with component or
> design-fetishism - this type of amp, this type
> of wire is absolutely the best.Perhaps.
> Fetishism, by definition, is the belief that certain
> properties are contained in some object which are not
> really contained in the object, but only in certain
> contexts in which the object occurs.In other words, a given thing may be considered relatively, in a given context, but not absolutley.
An example may be SE Valve or OTL Amplifiers and Apogee Scintilla Speakers or old 15 Ohm Tannoy Coaxials in GRF Autograph Enclosures. The SE Amp or OTL will be very much "a bad thing" in the system with the Apogees, while in the system with the Tannoys they would be both likely exceptional, as overall system. Equally, the Monster Krell Solid State Amp that would be "a good thing" with the Apogees would not sound too good with the Tannoys.
> One falls prey to it precisely when one is
> ignorant of the way in which the context works -
> eg, of the ways in which circuits actually work.Absolutely.
> So for an amateur like me, all I can do is to be
> very sceptical of what anyone who is not a real
> engineeer says about hi-fi,Hmmm. How do you define "real engineer"? It it someone who constantly bangs on about how great an engineer he is or somone who actually understands things? And how do you judge if you yourself do not understand the subject well enough?
As a degreed EE myself with experience in both industrial/military electronics and audio and as someone with quite a few years as sound/recording engineer I find myself highly sceptical of what many engineers claim about things audio/electronics. I have had enough time to collect practical experience which suggests that traditional theoretical foundations are sufficiently incomplete to be relied upon to the exclusion of other (empirical) methodes.
Therefore those subscribing to the orthodox readings of electronics (and acoustics/electroacoustics) suggest to me usually the presence of academics, as opposed to real engineers.
> except, at most, what something sounds like.
I would argue that few Audiophiles are qualified to comment on how something sounds, lacking sufficiently points of reference and schooling in critical listening, at least when it comes to commenting on anything beyond "what it sounds like to me".
Ciao T
I am actually planning an article for the British Journal of Aesthetics on hi fi - never been done before and I'm persuaded that hi fi raises some genuinely distinctive philosophical issues - or at least, they intrude practically in a way that is unusual. I am planning to interview several hi fi people (I can tell you who is on the list by email), which will also make the article rather unusual in a philosophical journal.As I say, it is not true that things sound or look to one as one think they do (though it is natural and excusable to think they do). The key is that (as philosophers long suspected, and empirical results have now demonstrated beyond doubt) the perceptual field arises independently of, and anterior to, cognitive/evaluative processing. For example, the phenomenon of blindsight: subjects with certain brain injuries can perceive things that they claim not to (this is shown by their propensity to guess correctly - or rather they think they are only guessing). Many other phenonemena point the same direction. Judgements based on perception can be influenced in many ways, and in perfect sincerity. That is why, for example, people will insist on the dramatic difference their new power cord makes to their system, without being in the slightest bit insincere in claiming to hear the difference. They are wrong about what they hear, as paradoxical as that sounds. Anyway if you are interested in contributing to the project, let me know (it would not be onerous in the slightest).
Hi,You may forgive me for declining, but like so much in modern science modern, so-called Philosophy has gone well past any point where it still is useful or relevant to me personally at least. I could not make any points any better than they have already been made by Bishop Berkley, Hume and Kant, if they do not suffice, what can I possibly add.
That said, I agree that people have a much greater acess to absolute reality than it may seem at times.
However music reproduction is in fact the art to maximally remove and isolate the listener from absolute reality and engender in her or him the perception of listening music and not to air vibration created by mechanical devices reacting imperfectly to electrical signals which imperfectly encode the airwaves from an original musical event.
Ciao T
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