In article , mick
wrote:
On Thu, 11 Nov 2004 06:34:47 +0000, Trevor Wilson wrote:


Trevor, I respect your point of view, but some research has been done
(and its not for me to judge how well) which shows that:

Frequency response - bottom end is limited by the volume of the room.

I am not sure why you say the above. I don't know of any research that
would support it as an unqualified statement. Indeed, if the room door is
closed it should be easier to generate sound pressures at LF in a room than
in the open with most forms of LF speaker (e.g. infinite baffle).


Output impedence of the amplifier - controlling the speaker damping - is
also inaudible to the majority of listeners unless it is *really* bad.

I am not sure what definitions you are using for phrases like " *really*
bad ". However the problem here is not usually one of "controlling speaker
damping". It is the amplifier o/p impedance and the i/p impedance of a
loudspeaker form a network which introduces a frequency-dependent
attenuation. Thus altering the frequency response.

THD is meanongless in the real world. It is a great method of producing
comparisons between amps, but there are so many other factors to be
taken into consideration that, below something like 5%, it is completely
inaudible.

That is not my experience. I have in the past heard distortion levels below
this. And my recollection is that the literature reports audibility for
distortions below 5%

FWIW I'm currently in the process of reading various papers on noise and
distortion w.r.t the vinyl/LP system as I'm in the process of writing
something on the performance. If you look, for example, at a paper like

"Psychoacoustics: the determining factor in Stereo Disc Distortion"
Jacobs and Whitman (Shure Bros) JAES April 1964 pp115-123 you will
see listed and summarised reports that indicate that distortions
in the range around 1% upwards are audible.


I'm not claiming that these are my own views. I generally don't consider
an amp bad unless I can hear the problems or it makes something smoke!

Since you say the above is based upon "some research" can you perhaps give
us references for the sources of the above? What you say does not seem to
completely agree with things I have read or experienced.

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

Paul Dormer wrote:

[BTW I'm still open minded about the possibility that vinyl and valves
have as-yet undiscovered attributes which distinguish them as superior
to digital and SS in some regard, although this is not what *current*
scientific knowledge tells us. Scientists are never wrong are they??]

Perhaps they do, but they also have some very easily measurable flaws...

I have some £200 interconnects. The quality of engineering is light
years ahead of budget interconnects and they'll last for decades...

How sure of that are you? and 200? pfft. cheapo crap.

And in case anyone is wondering, my choice of watch is a 5ukp
bungie-cord watch ..

I never wear wrist watches. Like you, I find them irritating

When you come over you can see what you think of my bungiewatch.

"Jim Lesurf" wrote


Your unstated assumption is that you are able to identify any changes
caused by amplifier 'distortion' as being caused by that mechanism and
not
being from other effects.


Only in the context of this thread - I make no such 'general' claims.


Is it not possible that the sound is sometimes
being altered in an audible way by distortion, but you don't always
recognise this change as being due to amplifier distortion?


Of course that's possible....


I am not clear of your view on this point, but will also ask: Is it
possible that you simply prefer a sound that has been altered by some
specific forms of distortion?


I'm a little surprised to see you going for this 'favourite easy score' -
much more the practice of the clowns who want to trick someone into
admitting a) there *is* a 'rosy glow' and b) they *prefer* it...

Try the simple approach - works with me every time: I've no real idea why I
(or, more importantly, my partner) prefers the sound achieved with valve
amps but we clearly do - night on night, day on day, never failing, never
faltering....

What labels people wish to try an attach to that is of no real concern to
me - if it's gamma rays from the Planet Zog making, say, Ry Cooder sound
more like my/our perception of 'Ry Cooder' then I'd have to put a tick in
the box marked 'Finds Gamma Ray Distortion Preferable'.....??

shrug

Other than the obvious (but soft) signal break-up when a valve amp is wicked
up too high into the wrong speakers, I do not suffer any form of
'distortion' that I can say I notice. Nor buzzes, nor rattles, nor hum
(except when the EAR phono goes off on one...) nor sibilence, nor funny
smells (except when breaking in a new Chinese amp - my second one has just
turned up)....

Just lovely, clear music with a broad stage, tons of tinkly bits, clear as
mountain air with the tiniest details and enough bass to make the doors
rattle in their frames like machine guns (MG42s, I'd say.....)



As Trevor has indicated, a problem here is that other items - notably
speakers and vinyl LP can produce distortion of levels that tend to be
quite high compared with some other items. Hence these may be affecting
your perception of the effects.


Yes, of course - all part of the overall scheme of things. Never said it
weren't......

"Jim Lesurf" wrote in message
...
In article , Keith G
wrote:


Got an amp which *doesn't* distort?? Not at all???

How low do you think the distortion level of an amplifier has to be for
the
effect of the distortion to become inaudible?


No idea.


i.e. if we were to produce two amplifiers which had fairly low levels of
distortion, at what levels of distortion do you think you could tell the
difference between them?

Ditto.



Also, if there is a level below which the distortion has no effect you can
detect, is that amp then not essentially


...what?



Well, consider what I ask above. Is it the case that at some point the
distortions become so small that they become un-noticable?


I'm sure they do - at both ends of the audible spectrum, but I can't claim
to *know* that...???


Like there are wise guys here and also idiots who put themselves through
a lot of extra effort and expense just to be bloody awkward or summat?
Have a little think for a minute - I don't know of *anyone* who uses
valves (or has got into valves) because he thinks they are *worse* than
ss amplification.....!!

That sounds reasonable, but what are you assuming about the relationship
between the subjective judgement "worse" and the measurable quantites that
indicate the level of distortion? Are you symultenously assuming that:

1) More distortion = "worse"

and

2) But valve amps are "better"

Therefore concluding that valve amps must have 'less distortion'.


Huh?

WTF are you going on about James? - Keep it simple, try 'nice' and 'not so
nice'.....????

If I thought you were simply trying to trip me up me old (academic) china,
or put words in my mouth like the 2.5 desperados in this group, I'd have to
slide you in the Gary with all the other clowns who are more interested in
some sort of personal, point-scoring crap here than actually contributing
anything of real interest or use.....



Or are you assuming that distortion has nothing to do with the "worse"
judgement?


Nope.


Or what relationship between 'distortion' and 'worse' are you assuming?


None whatsoever......

(Clue - I *never* 'assume' - I either find out for myself for sure, or I ask
someone I can trust....)

Now if people buying valve gear would just say its because they *prefer*
the sound rather than saying the sound is *better* (how can it be given
SS systems can reproduce it), there would be no problems :-)

Is it possible to prefer something and not think that it is better at
the same time?

Is it possible to prefer something and not think that it is better at the same
time?

After thinking this over a bit ( e.g. "I prefer to holiday on the French
Riviera than shin down a bannister that turns suddenly into a razor blade") I
reckon you're right there!

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

"Phil North" wrote in message
...

Now if people buying valve gear would just say its because they *prefer*
the sound rather than saying the sound is *better* (how can it be given
SS systems can reproduce it), there would be no problems :-)

Is it possible to prefer something and not think that it is better at the
same time?


Yep, I love/prefer my old Luxman tuner (or would, if I could get a decent
signal) but I bet it's not really in Leagues, Division 1 or 2 really....

Btw, the second amp finally turned up this afternoon - how's yours going??

Ian Molton wrote:
Nick Gorham wrote:

I am sure you will have studied physics, name me one case where
perception does reflect exactly what is actually going on ?


Ever looked at one of those pictures that looks like its moving but isnt?

Well, I am sitting looking at a monitor at the moment so that would count.

--
Nick

"Jim Lesurf" wrote in message

In article ,
Keith G wrote:


Got an amp which *doesn't* distort?? Not at all???

How low do you think the distortion level of an amplifier has to be
for the effect of the distortion to become inaudible?

Somewhere below 0.1%

i.e. if we were to produce two amplifiers which had fairly low levels
of distortion, at what levels of distortion do you think you could
tell the difference between them?

If I get to choose the distortion and the music, I can hear 0.1% distortion,
but much less than that is dicey.


Also, if there is a level below which the distortion has no effect
you can detect, is that amp then not essentially
....distortion free?

Yes.

As my old dad used to say: "Two wrongs do not make a right." **

In the case of some kinds of nonlinear distortion, two wrongs can make a
right. However, the probability that two randomly-chosen distortion sources
exactly compensating is zero.


Wise words, but let's get a little reality check here.

There's much tub-thumping about 'high fidelity' and 'straight wires
with gain' - like one type of amp absolutely fits these criteria and
another type don't. (Not to mention whatever input or amp is used,
the speakers and the room will have the final say, in any case....)

Well, consider what I ask above. Is it the case that at some point the
distortions become so small that they become un-noticable?

Absolutely, positively.

Like there are wise guys here and also idiots who put themselves
through a lot of extra effort and expense just to be bloody awkward
or summat? Have a little think for a minute - I don't know of
*anyone* who uses valves (or has got into valves) because he thinks
they are *worse* than ss amplification.....!!

That sounds reasonable, but what are you assuming about the
relationship between the subjective judgement "worse" and the
measurable quantites that indicate the level of distortion? Are you
symultenously assuming that:

1) More distortion = "worse"

and

2) But valve amps are "better"

Therefore concluding that valve amps must have 'less distortion'.

Or are you assuming that distortion has nothing to do with the "worse"
judgement?

Take a SS amp, add about 4-5 tubes that are not in the signal path but
receive power, and watch the tubies fall for it.

Keith G wrote:
"Phil North" wrote in message
...

Now if people buying valve gear would just say its because they *prefer*
the sound rather than saying the sound is *better* (how can it be given
SS systems can reproduce it), there would be no problems :-)

Is it possible to prefer something and not think that it is better at the
same time?



Yep, I love/prefer my old Luxman tuner (or would, if I could get a decent
signal) but I bet it's not really in Leagues, Division 1 or 2 really....


Ah, now I get it.. if you were to offer me a doner kebab or some sort of
lobster salad 9 times out of 10 I'd have the kebab. Stone cold sober too.

Btw, the second amp finally turned up this afternoon - how's yours going??


It's very good. I put the first Kings of Leon album (vinyl) on last
night and to my ears it was superb, a real WOW moment.
I had a quick listen to a Blur CD and was equally impressed, but I think
Metallica
may have to stay solid state for now - at least until I've tried them
out on my better speakers anyway.
Whatever my ears tell me is what I'll go with and I'm looking forward to
going through my music collection to see how it all sounds, but how to
find the time and go to work?