
December 11th 04, 08:07 PM
posted to uk.rec.audio
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If the cap fits
"Pooh Bear" wrote in message
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Iain M Churches wrote:
"Don Pearce" wrote in message
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Iain, your memory fails you. It was me that pointed out the error on
the diagram - and I did it quite nicely, with a joke. It was then me
that got "peppered with buckshot" for having the effrontery to point
out an error on a circuit that had been submitted for exactly that
purpose - peer review. (snip and paste)
OK, I got irritated by the flak, and went on to describe how the
circuit was going to work in practice (very poorly in this case). But
there - you go. I have had circuits peer reviewed on the past, and
pulled to pieces. That is why you do it.
d
Hello Don,
It may well me that my news server did not download all the messages to
that particular thread, because I saw no evaluation of the circuit, or
suggestions
of improvements (with reasons why they would be improvements)
The schematic was posted in a.b.s.e 'my latest 845'
Graham
Yes I saw the schematic, but I did not see the subsequent posts were the
OP was given the help and evaluation of his circuit for which he was asking.
My server seems to be lax sometimes in presenting some of the posts in
a particular thread.
Iain
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December 12th 04, 09:05 AM
posted to uk.rec.audio
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If the cap fits
On Sat, 11 Dec 2004 07:55:20 +0000, Nick Gorham
wrote:
Dave Plowman (News) wrote:
Have you actually made the Pinky MC pre-amp?
Huh?
Thought you read ukrav. Obviously not.
I have. If you haven't, I'd
suggest you do. It out performs any valve MC pickup in every possible
parameter.
Other than by my sym's its 1db down at 20k. I don't suggest this is a
fault as Stew has mentioned that he built it to match the response of
his cartridge, but unless you use the same cartridge, then, I would
question your statement, in that its quite possible to produce a valve
phono stage that is closer to flat than that.
http://www.lurcher.org/nick/audio/Stew_Phono.gif
Three points:
1) Your simulation is incorrect. Without R1/C1 rolling off the
response above 2122Hz as required for RIAA correction, the amplifier
is flat to more than 100kHz. This is a *measured* response, and the
-3dB point is above 200kHz, when the circuit is driven from a 12 ohm
source. Replace R1/C1, and the circuit conforms to the RIAA curve
within 0.1dB from 20Hz to 20kHz. Since the nominally perfect HF
response is obvious from even a casual inspection of the circuit, you
should check either your opamp models, or your inverse RIAA circuit.
2) The gain and input impedance are set to match the A-T OC9, there is
no frequency tailoring other than the capacitance loading of C14. Any
builder can match his own cart by adjusting the values of C14, R11,
R12 and R14 to give suitable input impedance and gain. Note that
Nick's simulation did not include the input stage, so this cannot
affect his results.
3) Aside from the RIAA response, that circuit has about 10dB lower
noise than is possible using valves, and has almost unmeasurable
distortion, certainly well below 0.01% up to 30kHz. If properly laid
out with good earth paths, it also has hum which is below the noise
floor. Try that with valves!
--
Stewart Pinkerton | Music is Art - Audio is Engineering
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December 12th 04, 09:23 AM
posted to uk.rec.audio
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If the cap fits
Iain M Churches wrote:
snip
How long will it be before we shall see an "X" on contractual agreements,
beneath which a clerk has written "John Smith, his mark" as was common
in the early part of the 19th century?
Iain
Literacy and numeracy is an issue. I've been teaching adults in various
places - universities, colleges - for a long time now, and the standard
of written English falls well behind conventions. It's also a source of
staff room politics - is it 'English matters' or 'communicating the
message matters'? (I do teach in inner London - first language often
isn't English). Also, I'd estimate half of my undergraduate students
(business studies, social policy) and 3/4 of adult ed. can't calculate a
percentage.
I'm a bit of of a 'grammar fascist' on the quiet, although I don't think
I've marked down because of it. (makes me smile in this NG - many of the
literacy critics often make mistakes!).
And tempted as I am, can't 'blame the Tories' as such - TV and
calculators, and simply not needing basic concepts (apostrophe,
fractions) just puts them out of use for entire generations.
Next - maps! Satellite navigation systems, don't go there :-)
Rob
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December 12th 04, 09:23 AM
posted to uk.rec.audio
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If the cap fits
On Sat, 11 Dec 2004 16:32:23 +0200, "Iain M Churches"
wrote:
"Keith G" wrote in message
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"Dave Plowman (News)" wrote in message
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In article ,
Keith G wrote:
Oh, feck me - don't tell me that **** still thinks he can teach his
betters how to speak proper English??
As wot u rite?
I don't take exception at all at Chris Morriss' concern with grammar.
There is every indication that the general standard of English is in
sharp decline, and with 7million in the UK with poor literacy skills
we should all be concerned.
y wd it b a prob 4 u if u r a txtr?
Now, I don't doubt that you understood exactly what I wrote above,
even if you have never seen a mobile phone text message. While I do
try to generate grammatically correct prose, I also understand that
language exists for the sole purpose of communication. Hence, so long
as one is clear and unambiguous, does it matter if you wish to boldly
split infinitives where no infinitive has been split before? Despite
the squeals of English teachers, it's a plain fact that for many
centuries, English spelling and grammar have been fluid and evolving.
In German, of course, any deviation or exception vill be schott!
How long will it be before we shall see an "X" on contractual agreements,
beneath which a clerk has written "John Smith, his mark" as was common
in the early part of the 19th century?
The difficulty will lie in finding a literate clerk...................
--
Stewart Pinkerton | Music is Art - Audio is Engineering
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December 12th 04, 09:28 AM
posted to uk.rec.audio
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If the cap fits
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December 12th 04, 09:29 AM
posted to uk.rec.audio
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If the cap fits
On Sat, 11 Dec 2004 15:26:24 +0000, Chris Morriss
wrote:
In message , Keith G
writes
I like a bit of arguous-barguous, as you know, but I still think Iain is
only expressing his dismay at the 'clearly you are an idiot' type of remark
that he got from pinky in response to perfectly polite comments. (Pinky's
SOP when he comes up against someone *professionally* connected to the
'audio world', if you haven't noticed - it's an 'envy' thing... ;-)
No, it's an accuracy thing, and is my SOP when someone posts something
which is clearly idiotic - such as Iain did. AFAIK, the current
reigning idiot, Andy Evans, has no 'professional' connection to the
audio industry.
There are a number of us here, as far as I can see, that are
professionals in audio matters. I am employed to design (among other
things) switch-mode PSUs and class-D audio amplifiers. The new terminal
5 at Heathrow will have nearly all the analogue audio i/o for the
Cobranet digital audio networking of my design. Whether that puts you
off using T5 of course is up to you :-)
I used to be employed to design torpedo circuitry which operates in
the audio band (especially if you consider that the music industry now
seems to believe that the audio band has a dynamic range of 144dB and
a bandwidth of 96kHz, which is about what I was using in the early
'80s!). I guess that counts as a 'professional connection'..... :-)
--
Stewart Pinkerton | Music is Art - Audio is Engineering
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December 12th 04, 10:07 AM
posted to uk.rec.audio
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If the cap fits
Jim Lesurf wrote:
In article , Iain M Churches
wrote:
I don't take exception at all at Chris Morriss' concern with grammar.
There is every indication that the general standard of English is in
sharp decline, and with 7million in the UK with poor literacy skills we
should all be concerned.
How long will it be before we shall see an "X" on contractual
agreements, beneath which a clerk has written "John Smith, his mark" as
was common in the early part of the 19th century?
Having worked in the 'ed biz' for many years, I share your concerns.
HFW has to be most poorly edited and written 'mainstream' magazine I
have come across. It is atrocious. And that's before I get to the
content ;-).
However for the same reasons I have my worries about what I have started to
think might be called "faith based engineering".
I am worried that there is a decline in the UK in the number of people who
have a genuine interest and understanding of both engineering and physical
science.
I think that's a shame - I've just read that a major university physics
department has closed down.
Alas, my impression is that although audio can serve as an
excellent route for getting people into understanding these areas, it often
fails to do so. People become interested, but sometimes seem to treat audio
engineering as almost a branch of 'magic'. :-/
I'm not sure of your angle here. Audio engineering 'advances' appear to
me to be along the lines of digital amps, compression, multi-channel,
video enhanced, portability - I'd imagine little of the innovation is UK
based, but this may have as much to do with application opportunities as
having and nurturing the idea. Is this what you mean by 'faith based
engineering'?
If it's a reference to valves (say) - I skim your exchanges with patrick
Turner (et al) and frankly it looks like semantics - I'd guess that
you're both 'right' (as if I'd know!). They're just different designs of
the same thing. Now, whether one is 'better' than the other is the
subject of some dispute. I wish we could all settle on preference. The
point, I suupose, from a design point of view is that one *depends* on
quantitative criteria, one doesn't. Are you saying that Sony's designs
of amplifiers are better than valve amps designed by (say) Audio
Innovations? Does one rely on 'science', and one rely on 'faith'?
For both design paradigms I feel that a lot of nonsense comes into the
equation, with badge engineering and needlessly esoteric bits bolted
on/in. But this isn't 'faith based engineering' - it's marketing. I
don't believe that Ken Ishiwata has 'faith' in many of the things he
does - he just panders to a market. But I wouldn't say that he's a
designer reliant on mysticism.
For that reason I'm afraid that I do sometimes see some of the things
people say in newgroups like this one (and in magazines, and elsewhere) as
being engineering parallels with using an 'X' due to an inability to write
out their name!
That's quite extreme! A different dialect maybe, but illiterate, not sure.
Rob
Slainte,
Jim
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December 12th 04, 10:24 AM
posted to uk.rec.audio
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If the cap fits
"Stewart Pinkerton" wrote in message
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On Sat, 11 Dec 2004 15:26:24 +0000, Chris Morriss
wrote:
No, it's an accuracy thing, and is my SOP when someone posts something
which is clearly idiotic - such as Iain did.
I made an error, for which I aplogised. I don't
think this has anything to do with idiocy. It is unfortunate
that we cannot all meet your standard of perfection, Stewart,
even though we do try:-)
In contrast, I am told that on RAT they are clubbing
together to buy you a hat with a bell, like Noddy wore.
Is it true?
I used to be employed to design torpedo circuitry which operates in
the audio band (especially if you consider that the music industry now
seems to believe that the audio band has a dynamic range of 144dB and
a bandwidth of 96kHz, which is about what I was using in the early
'80s!). I guess that counts as a 'professional connection'..... :-)
Torpedoes have only a tenuous connection with
audio, even though they do make a big bang. And
"making" music is a far cry from "destroying" other
nations' shipping. Though I am sure we are all
deeply grateful to you for allowing us to sleep more
safely in our beds:-))
Neverthless, your experience would not gain you
acceptance to the AES except possible at student level:-)
Kunnoittaen
Iain
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December 12th 04, 10:52 AM
posted to uk.rec.audio
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If the cap fits
Stewart Pinkerton wrote:
On Fri, 10 Dec 2004 13:49:06 +0000 (GMT), "Dave Plowman (News)"
wrote:
If you wish such a group - where say valvies can discuss their hobby and
make the most outrageous claims with impunity - then you need to set up a
group where that is in the charter.
Audio Asylum. Any discussion involving DBT, i.e. actually *proving*
the truth behind your opinions, is banned by the censors.
Audio Asylum, what an appropriate name!
So the inmates don't believe in blind testing?
(betcha they believe in cable sound!)
Did the censors say why they banned discussion about DBT?
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