On Thu, 20 Nov 2008 18:03:22 +0000, Goofball_star_dot_etal
wrote:

On Thu, 20 Nov 2008 17:36:49 GMT, (Don Pearce) wrote:



What is that a plot of, and what is the software?


Frequency (r) v rotation of platter (theta) for about ten seconds of
your file, with the start cut off.

Just something I knocked up a few years ago in Labview. 'Software FM
radio'?

OK, I get what you've done. Can you tell me about the number of points
in the sliding sample, windowing etc? I'm thinking those fine wiggles
are probably artefacts of the maths.

d
--
Pearce Consulting
http://www.pearce.uk.com

On Thu, 20 Nov 2008 18:16:17 GMT, (Don Pearce)
wrote:

On Thu, 20 Nov 2008 18:03:22 +0000, Goofball_star_dot_etal
wrote:

On Thu, 20 Nov 2008 17:36:49 GMT, (Don Pearce) wrote:



What is that a plot of, and what is the software?


Frequency (r) v rotation of platter (theta) for about ten seconds of
your file, with the start cut off.

Just something I knocked up a few years ago in Labview. 'Software FM
radio'?

OK, I get what you've done. Can you tell me about the number of points
in the sliding sample, windowing etc? I'm thinking those fine wiggles
are probably artefacts of the maths.

d

I don't have it running on this computer at the moment but from
memory.. after demodulation it was filtered with a 60 Hz low pass
filter. I think 1000 points was selected but there is decimation
involved somewhere and I can also choose the window function. It was
a long time ago when I knew how it worked. but it was very well
behaved. I think the fine ripple is real between 40-50 Hz. The biggest
peak was about three times the platter rotational frequency.

Some of the old files I did can still be found at:
http://www.wareing77.plus.com/turntable-web.htm

Jim Lesurf wrote:
In article , Don
Pearce
wrote:
Jim Lesurf wrote:


Odd that - I would expect crosstalk performance to depend mostly on the
accuracy of the right angle between the two coils with some secondary
effects from the cantilever mounting. No real reason for either of those
to be so poor.

Indeed. I am also puzzled (as well as dissapointed) by this. Seems to me to
be a sign that something isn't right. I spent more time on the M97s than
anything else, trying to see if the results could be improved. But in the
end I decided the values I was getting were about it. Nor did the crosstalk
seem to be due to distortion. Maybe the stylus is 'rotating' because the
mass and force are off the cantilever/suspension axis. Dunno. Gave up
puzzling over this and published the results.

Also surprised by the stark differences shown by the photos of the
stylus of the 97xE compared with the old HE and MR. Chalk and cheese.


I spy cost-cutting.

Maybe. Again this was quite a surprise for me given the superb V15.


FWIW one 'feature' I didn't comment on in the mag is that if you look
at the responses you can see a 'kink' in most of them. This seems to
depend on the headshell and the level of the cartridge's effective
compliance, etc.


I noticed that kink (you do mean the one around 200Hz?).

Yes.

I can't find any trace of it on my system in normal use, but there is
just a hint of it on the crosstalk test. I do wonder just how good the
cutter that makes test discs is compared to the cartridges that we use
to reproduce them. I suspect that for many tests the answer is - not
much better.

I also wondered about that. But it showed up to a different extent (and
frequency!) when I changed from one cart+headshell to another. My guess is
that the V15 has high compliance and tiny mass, so delivers minimal
vibration into the arm. But the other carts aren't as good in this respect,
so excite more in spurious arm or headshell resonances. The 97 does look as
if it has a much bigger effective tip mass than the V15, so a static
compliance value may not give the game away.

For convenience I used more than one headshell, so they may also differ.

May sometime do more precise plots with noise and time-averaged spectra.
But I didn't do that here as they need to be corrected for the recorded
response[1], and I also wanted to extract THD values. The stepped sinewaves
on the 'Ultimate Analog' test LP were excellent for this. But the stepped
waveforms were more tedious to use than noise. Was meaning to also do
crosstalk versus frequency, but again ran out of time and patience! Another
day, maybe.


Here you go, got that for you - the AT OC9 again:

http://81.174.169.10/odds/croddtalk_oc9.gif

All those odd resonances are there on the crosstalk channel, but it does
manage 30dB midband. Could do with a good long noise track, a minute or
so, to make better plots.

By then end of that article I wanted a break from 4 in a row about LP. So
ended up doing at least four on speaker cables! Must be mad. 8-]

Been told that the second cables article is now out, but not seen it as
yet.

Slainte,

Jim

[1]I have done some responses with various 'noise bands' on test LPs, and
they seem to give a wild variety of results. Results generally neither
pink, nor flat, not anything else that would make obvious sense. Prompt for
a latin tag about who guards the guardians... :-)


That would be Quis custodiet ipsos custodes.

d

Don Pearce wrote:
Jim Lesurf wrote:
In article , Don
Pearce
wrote:
Jim Lesurf wrote:


Odd that - I would expect crosstalk performance to depend mostly on the
accuracy of the right angle between the two coils with some secondary
effects from the cantilever mounting. No real reason for either of those
to be so poor.

Indeed. I am also puzzled (as well as dissapointed) by this. Seems to
me to
be a sign that something isn't right. I spent more time on the M97s than
anything else, trying to see if the results could be improved. But in the
end I decided the values I was getting were about it. Nor did the
crosstalk
seem to be due to distortion. Maybe the stylus is 'rotating' because the
mass and force are off the cantilever/suspension axis. Dunno. Gave up
puzzling over this and published the results.

Also surprised by the stark differences shown by the photos of the
stylus of the 97xE compared with the old HE and MR. Chalk and cheese.


I spy cost-cutting.

Maybe. Again this was quite a surprise for me given the superb V15.


FWIW one 'feature' I didn't comment on in the mag is that if you look
at the responses you can see a 'kink' in most of them. This seems to
depend on the headshell and the level of the cartridge's effective
compliance, etc.


I noticed that kink (you do mean the one around 200Hz?).

Yes.

I can't find any trace of it on my system in normal use, but there is
just a hint of it on the crosstalk test. I do wonder just how good the
cutter that makes test discs is compared to the cartridges that we use
to reproduce them. I suspect that for many tests the answer is - not
much better.

I also wondered about that. But it showed up to a different extent (and
frequency!) when I changed from one cart+headshell to another. My
guess is
that the V15 has high compliance and tiny mass, so delivers minimal
vibration into the arm. But the other carts aren't as good in this
respect,
so excite more in spurious arm or headshell resonances. The 97 does
look as
if it has a much bigger effective tip mass than the V15, so a static
compliance value may not give the game away.

For convenience I used more than one headshell, so they may also differ.

May sometime do more precise plots with noise and time-averaged spectra.
But I didn't do that here as they need to be corrected for the recorded
response[1], and I also wanted to extract THD values. The stepped
sinewaves
on the 'Ultimate Analog' test LP were excellent for this. But the stepped
waveforms were more tedious to use than noise. Was meaning to also do
crosstalk versus frequency, but again ran out of time and patience!
Another
day, maybe.


Here you go, got that for you - the AT OC9 again:

http://81.174.169.10/odds/croddtalk_oc9.gif



Sorry about that

I do of course mean

http://81.174.169.10/odds/crosstalk_oc9.gif

d

Arny Krueger wrote:
"Jim Lesurf" wrote in message

Just posting to let people know that audiomisc.co.uk now
includes a web version of the 4th article in my recent
HFN series on LP. This one provides measured results for
the old Shure V15/III and compares it with some modern MM
carts. Also has some close up photos of each stylus, etc.

With no exact link, it took me about 5 minutes to actually find the page.
:-(

The URL is http://www.audiomisc.co.uk/HFN/LP4/NewLampsForOld.html


I notice that the red plastic stylus 'handle' on Jim's V15 is aligned
just as badly as mine was.
I wish I knew what happened to my V15 when I moved house. :-(

--
Eiron.

Jim Lesurf wrote:
Just posting to let people know that audiomisc.co.uk now includes a web
version of the 4th article in my recent HFN series on LP. This one provides
measured results for the old Shure V15/III and compares it with some modern
MM carts. Also has some close up photos of each stylus, etc.

Slainte,

Jim


I'm not quite sure of the point of the comparables - the cartrdiges
you've used are a fraction of the price of the Shure V15. Are you trying
to evaluate the effectiveness of modern/mass production?

Whatever, an interesting experiment. Couple of qs:

1. I've been buying cartridges from LP Gear for more than 10 years now,
and I've been very pleased with their service/prices. Might this do the
trick for a V15:

http://www.lpgear.com/Merchant2/merc... e=SHVN35HESAS

2. How might I estimate correct cartridge loads? You make references to
changing loads quite frequently - does this need arise as a result of
istening, manufacturer specs, measurements?

Slightly off topic, I've been using an AT440 for the past 6 months, in
place of an ATOC9 which I couldn't get to sound 'right' with an old SME
tonearm. *Very* impressed, and one of the very few cartidges I've used
able to track inner grooves properly.

Rob

In article , Eiron
wrote:
Arny Krueger wrote:
"Jim Lesurf" wrote in message

Just posting to let people know that audiomisc.co.uk now includes a
web version of the 4th article in my recent HFN series on LP. This
one provides measured results for the old Shure V15/III and compares
it with some modern MM carts. Also has some close up photos of each
stylus, etc.

With no exact link, it took me about 5 minutes to actually find the
page.
:-(

The URL is http://www.audiomisc.co.uk/HFN/LP4/NewLampsForOld.html


I notice that the red plastic stylus 'handle' on Jim's V15 is aligned
just as badly as mine was.

Yes, it is visibly skewed. However the results indicate that the actual
cantilever, etc, are very well aligned so this seems to be a cosmetic
problem. Less obvious if not looking at a 'macro' view. :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Rob
wrote:
Jim Lesurf wrote:
Just posting to let people know that audiomisc.co.uk now includes a
web version of the 4th article in my recent HFN series on LP. This one
provides measured results for the old Shure V15/III and compares it
with some modern MM carts. Also has some close up photos of each
stylus, etc.


I'm not quite sure of the point of the comparables - the cartrdiges
you've used are a fraction of the price of the Shure V15. Are you trying
to evaluate the effectiveness of modern/mass production?

The point was to see what might serve as a 'drop in replacement' if a V15
were to finally become unservicable. I felt (and feel) than a number of
people have stuck with the V15 for what they regard as good reasons, so was
curious to explore what to do when that option times out!

Thus I kept to MM designs and didn't attempt to change the
preamp/loading/arm/TT at all. Hence did a comparison of the old V15 HE
and MR with the newer examples. As the text explained, I chose the Rega
Exact as I happened to have it, and it was a UK maker, and the M2 Black
because it was a new design with good reviews.

I might have included some others, but as it was the tests took me a lot of
time. So I am not rushing to do more for a while. :-)

Whatever, an interesting experiment. Couple of qs:

1. I've been buying cartridges from LP Gear for more than 10 years now,
and I've been very pleased with their service/prices. Might this do the
trick for a V15:

http://www.lpgear.com/Merchant2/merc... e=SHVN35HESAS

Well look at that later when I get a chance. :-)

2. How might I estimate correct cartridge loads? You make references to
changing loads quite frequently - does this need arise as a result of
istening, manufacturer specs, measurements?

It would be primarily to adjust the frequency response. Might also affect
some other things like distortion levels. So tweaks the behaviour.

The optimum would depend on what you wanted (and also depends on the
accuracy of the RIAA, etc). But the idea is to try and flatten out the
typical MM behaviour of a 'dip' in the few kHz region with a 'peak'
somewhere up at hf.

You can do this by some mix of measurement, trying different R and C
loadings, and knowing the output resistance and inductance of the
particular cartridge. IIRC The specs for the M2 Black allow the same load
capacitance as the Shures, but my results make me think that this isn't
optimum.

So I'd expect you could get somewhat flatter response from the M2 bt
changing the loading, and could probably get a closer behaviour to the V15.
But I don't know how much effect you could have on the Exact. Hope to do
more on this sometime.

May also sometime extend to comparing with modern MC examples. But for the
article I did I wanted to avoid all the extra variables of choosing a step
up device, different preamp, and so on. So ignored MC.

Slightly off topic, I've been using an AT440 for the past 6 months, in
place of an ATOC9 which I couldn't get to sound 'right' with an old SME
tonearm. *Very* impressed, and one of the very few cartidges I've used
able to track inner grooves properly.

That is one of the reasons I like the V15 HE and MR. Despite the names 'HE'
and 'MR' their tip shapes don't seem as cleverly contoured as some modern
carts. But the low tip mass, etc, mean they can actually easily track what
others struggle to cope with. Having a theoretically superb contour doesn't
work miracles if the stylus has a mass of a ton or the cantilever is stiff
or has no damping. My view is that Shure tended to score because they got
the general mechanical engineering right. Alas, they don't seem to do as
well nowdays, presumably because their interest isn't in this in the same
way as it used to be!

I suspect that if Shure found a box of NOS V15/iii's in as-new condition
there'd be a long queue to buy them! I'd certainly be in the queue. :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Jim Lesurf
wrote:
In article , Rob
wrote:

1. I've been buying cartridges from LP Gear for more than 10 years
now, and I've been very pleased with their service/prices. Might this
do the trick for a V15:

http://www.lpgear.com/Merchant2/merc... e=SHVN35HESAS

Well look at that later when I get a chance. :-)

Just looked at the above. It makes a song and dance about stylus shape and
fancy materials. However I didn't see any data that relates to something
else I said in my past posting...

That is one of the reasons I like the V15 HE and MR. Despite the names
'HE' and 'MR' their tip shapes don't seem as cleverly contoured as some
modern carts. But the low tip mass, etc, mean they can actually easily
track what others struggle to cope with. Having a theoretically superb
contour doesn't work miracles if the stylus has a mass of a ton or the
cantilever is stiff or has no damping. My view is that Shure tended to
score because they got the general mechanical engineering right. Alas,
they don't seem to do as well nowdays, presumably because their interest
isn't in this in the same way as it used to be!

So what the 'lpgear' page says doesn't give my any idea if their stylus is
any good or not. Do they give any values for tip mass, static compliance,
or 'trackability' values to compare with the original? If not, then having
a superb tip shape doesn't guarantee good results, I'm afraid.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Jim Lesurf wrote:
In article , Jim Lesurf
wrote:
In article , Rob
wrote:

1. I've been buying cartridges from LP Gear for more than 10 years
now, and I've been very pleased with their service/prices. Might this
do the trick for a V15:

http://www.lpgear.com/Merchant2/merc... e=SHVN35HESAS

Well look at that later when I get a chance. :-)

Just looked at the above. It makes a song and dance about stylus shape and
fancy materials. However I didn't see any data that relates to something
else I said in my past posting...

That is one of the reasons I like the V15 HE and MR. Despite the names
'HE' and 'MR' their tip shapes don't seem as cleverly contoured as some
modern carts. But the low tip mass, etc, mean they can actually easily
track what others struggle to cope with. Having a theoretically superb
contour doesn't work miracles if the stylus has a mass of a ton or the
cantilever is stiff or has no damping. My view is that Shure tended to
score because they got the general mechanical engineering right. Alas,
they don't seem to do as well nowdays, presumably because their interest
isn't in this in the same way as it used to be!

So what the 'lpgear' page says doesn't give my any idea if their stylus is
any good or not. Do they give any values for tip mass, static compliance,
or 'trackability' values to compare with the original? If not, then having
a superb tip shape doesn't guarantee good results, I'm afraid.

Slainte,

Jim


No, I know, I was just curious. They seem to be a decent specialist
company - the possibility that they've sourced a worthwhile replacement
stylus could be worth investigating perhaps. Not by you at all
necessarily mind - you've done your bit!

Rob