Cartridge response - pink noise test
 

In message , Don Pearce
writes
On Sun, 22 Oct 2006 16:29:12 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Fri, 20 Oct 2006 19:41:05 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Thu, 19 Oct 2006 23:25:17 +0100, Kevin Seal wrote:

snip.

http://81.174.169.10/odds/dspkr/v15pink3.gif

Depending on by how much the capacitance has changed, I would say that
the V15-5 was the least sensitive of the V15's to capacitance loading.
The V15-3 being the most sensitive!

The numbers don't support you here. The V15-3 had an inductance of
500mH, and the V15-5 was much higher at 720mH. That would make the 5
far more sensitive to things capacitive than the other.

From the Shure website.....

V15-V
Inductance 330mH
DC resistance 815 Ohms

V15-3
Inductance 500mH
DC resistance 1350 Ohms.

With regards to Arny's post, the V15-3's response would be affected from
about 1kHz upwards if loaded with only half it's required capacitance.
The response would droop from 1kHz then rise to a peak at around 8 to
10kHz, then drop off again as it approached 20Khz.

I've done the maths for V15-III and V15-V using these numbers, and the
results are here. Note that they are relative only, and do not reflect
the actual flatness of the cartridge, which will also depend on
mechanical factors.

http://81.174.169.10/odds/v15iii/cartridge.html
http://81.174.169.10/odds/v15v/cartridge.html

The V15-V appears to be more heavily influenced by the load
capacitance.

I can only go by practical experience. Ten years testing cartridges
using an SME 3009S2 Improved tone arm, Thorens TD125 deck in SME plinth,
B & K test equipment and records.
The results were that the V15V was much less susceptible to capacitive
loading than the V15III.
And as I said above, the effects of too lower a capacitance was that the
response sagged from 1kHz by a good half to one dB before peaking as per
your plots.
I'm no good at maths on this scale, but all plots I ran all Shure
cartridges (and other brand MM cartridges) always showed a dip before
the peak.

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}

Cartridge response - pink noise test
 

In message , Arny Krueger
writes
"Kevin Seal" wrote in message

In message
, Arny
Krueger writes
"Don Pearce" wrote in message

On Fri, 20 Oct 2006 19:41:05 +0100, Kevin Seal
wrote:

In message , Don
Pearce writes
On Thu, 19 Oct 2006 23:25:17 +0100, Kevin Seal
wrote:

snip.

http://81.174.169.10/odds/dspkr/v15pink3.gif

Depending on by how much the capacitance has changed,
I would say that the V15-5 was the least sensitive of
the V15's to capacitance loading. The V15-3 being the
most sensitive!

The numbers don't support you here. The V15-3 had an
inductance of 500mH, and the V15-5 was much higher at
720mH. That would make the 5 far more sensitive to
things capacitive than the other.

From the Shure website.....

V15-V
Inductance 330mH
DC resistance 815 Ohms

V15-3
Inductance 500mH
DC resistance 1350 Ohms.

With regards to Arny's post, the V15-3's response would
be affected from about 1kHz upwards if loaded with only
half it's required capacitance. The response would
droop from 1kHz then rise to a peak at around 8 to
10kHz, then drop off again as it approached 20Khz.

I've done the maths for V15-III and V15-V using these
numbers, and the results are here. Note that they are
relative only, and do not reflect the actual flatness of
the cartridge, which will also depend on mechanical
factors.

http://81.174.169.10/odds/v15iii/cartridge.html
http://81.174.169.10/odds/v15v/cartridge.html

The V15-V appears to be more heavily influenced by the
load capacitance.

These curves look a lot like practical reality as I saw
it, back in the days when vinyl was all we had.

The top end is typical shape, but in reality, there
should be a sag in the mid range.

I would suggest that the performance of the mechanical
system was not very much influenced by the cartrdige
loading at that these curves pretty well added to its
response a linear fashion like cascaded amplifier
stages.
I'm sorry Arny, I've read it three times now, but I still
am not sure what you are saying! :)


OK - a cartridge can be thought of as being two subsytems - the mechanical
subsystem composed of the stylus, moving magnet and suspension, and the
electrical subsystem composed of the pickup coil, and the circuit that loads
it which is composed of a resistor and capacitor in parallel. They are
coupled by a varying magnetic field.

In general, the mechanical and electrical systems interact to some degree.
In this case it seems like the interaction is mostly one-way, from the
stylus assembly and moving magnet, to the pickup coil.

Both the mechanical subsystem and the electrical subsystem have frequency
response characteristics, like equalizers. Because there is very little
reverse coupling, the response of the whole system seems to be a lot like
two equalizers that are cascaded the usual way.


Yes I know and understand that, I just couldn't decipher the gramma of
wot U rote! :)
--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}

Cartridge response - pink noise test
 

On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

d

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

--
Posted via a free Usenet account from http://www.teranews.com

Cartridge response - pink noise test
 

In message , Don Pearce
writes
On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

I understand perfectly what you are saying. But what you won't accept is
that your maths do not show the truth, the V15V was less affected by
capacitance loading than the V15III.
--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}

Cartridge response - pink noise test
 

On Mon, 23 Oct 2006 23:05:05 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

I understand perfectly what you are saying. But what you won't accept is
that your maths do not show the truth, the V15V was less affected by
capacitance loading than the V15III.

The V15III requires double the load capacitance of the V15V so a given
change in total absolute capacitance will constitute only half the
percentage change in relative capacitance. There will therefore be
less variation as a result. That is reflected in my results, but is
not the point I am making.

d

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

--
Posted via a free Usenet account from http://www.teranews.com

Cartridge response - pink noise test
 

In message , Don Pearce
writes
On Mon, 23 Oct 2006 23:05:05 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

I understand perfectly what you are saying. But what you won't accept is
that your maths do not show the truth, the V15V was less affected by
capacitance loading than the V15III.

The V15III requires double the load capacitance of the V15V so a given
change in total absolute capacitance will constitute only half the
percentage change in relative capacitance. There will therefore be
less variation as a result.

That's easy for you to say! :)


That is reflected in my results, but is
not the point I am making.

Having looked at your graphs again, I see that they are in fact totally
wrong.
Increased capacitance will actually *decrease* the HF response.
Hence why people found the V15III bright and harsh, because they had not
applied the correct capacitance load.
--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}

Cartridge response - pink noise test
 

On Tue, 24 Oct 2006 18:52:21 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 23:05:05 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

I understand perfectly what you are saying. But what you won't accept is
that your maths do not show the truth, the V15V was less affected by
capacitance loading than the V15III.

The V15III requires double the load capacitance of the V15V so a given
change in total absolute capacitance will constitute only half the
percentage change in relative capacitance. There will therefore be
less variation as a result.

That's easy for you to say! :)


That is reflected in my results, but is
not the point I am making.

Having looked at your graphs again, I see that they are in fact totally
wrong.
Increased capacitance will actually *decrease* the HF response.
Hence why people found the V15III bright and harsh, because they had not
applied the correct capacitance load.

My graphs are wrong? They derive from my maths, which is shown as
well. If that is wrong, please show me the error - I'm always eager to
learn. If you are saying that while my calculations are correct, the
result is wrong, then I will have to ask you where Shure got
permission to abdicate from the real physical world.

d

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

--
Posted via a free Usenet account from http://www.teranews.com

Cartridge response - pink noise test
 

In message , Don Pearce
writes
On Tue, 24 Oct 2006 18:52:21 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 23:05:05 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

I understand perfectly what you are saying. But what you won't accept is
that your maths do not show the truth, the V15V was less affected by
capacitance loading than the V15III.

The V15III requires double the load capacitance of the V15V so a given
change in total absolute capacitance will constitute only half the
percentage change in relative capacitance. There will therefore be
less variation as a result.

That's easy for you to say! :)


That is reflected in my results, but is
not the point I am making.

Having looked at your graphs again, I see that they are in fact totally
wrong.
Increased capacitance will actually *decrease* the HF response.
Hence why people found the V15III bright and harsh, because they had not
applied the correct capacitance load.

My graphs are wrong? They derive from my maths, which is shown as
well. If that is wrong, please show me the error - I'm always eager to
learn. If you are saying that while my calculations are correct, the
result is wrong, then I will have to ask you where Shure got
permission to abdicate from the real physical world.

What I am saying is, if you run a frequency reponse test using the gear
I mentioned in a previous post, and load the V15III with 250pF, the HF
will peak.
If you then increase the load to 450pF, the HF will flatten out.
This is the total opposite of what your graphs show.
--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}

Cartridge response - pink noise test
 

On Tue, 24 Oct 2006 23:48:43 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Tue, 24 Oct 2006 18:52:21 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 23:05:05 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

I understand perfectly what you are saying. But what you won't accept is
that your maths do not show the truth, the V15V was less affected by
capacitance loading than the V15III.

The V15III requires double the load capacitance of the V15V so a given
change in total absolute capacitance will constitute only half the
percentage change in relative capacitance. There will therefore be
less variation as a result.

That's easy for you to say! :)


That is reflected in my results, but is
not the point I am making.

Having looked at your graphs again, I see that they are in fact totally
wrong.
Increased capacitance will actually *decrease* the HF response.
Hence why people found the V15III bright and harsh, because they had not
applied the correct capacitance load.

My graphs are wrong? They derive from my maths, which is shown as
well. If that is wrong, please show me the error - I'm always eager to
learn. If you are saying that while my calculations are correct, the
result is wrong, then I will have to ask you where Shure got
permission to abdicate from the real physical world.

What I am saying is, if you run a frequency reponse test using the gear
I mentioned in a previous post, and load the V15III with 250pF, the HF
will peak.
If you then increase the load to 450pF, the HF will flatten out.
This is the total opposite of what your graphs show.

Show me.

d

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

--
Posted via a free Usenet account from http://www.teranews.com

Cartridge response - pink noise test
 

In message , Don Pearce
writes
On Tue, 24 Oct 2006 23:48:43 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Tue, 24 Oct 2006 18:52:21 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 23:05:05 +0100, Kevin Seal wrote:

In message , Don Pearce
writes
On Mon, 23 Oct 2006 19:03:29 +0100, Kevin Seal wrote:

As I said, I am not saying these show the response of the cartridge,
which has many mechanical factors affecting it. What my posts show is
the way the response *changes* with capacitive loading. There could be
all sorts of lumps, bumps and sags in the actual response, but that is
not what I'm dealing with.

But if your maths do not show what real world tests produce, surely
something is missing from the equation?
--

Sorry, Kevin, I'm not explaining this again. If you haven't understood
by now I have to give up.

I understand perfectly what you are saying. But what you won't accept is
that your maths do not show the truth, the V15V was less affected by
capacitance loading than the V15III.

The V15III requires double the load capacitance of the V15V so a given
change in total absolute capacitance will constitute only half the
percentage change in relative capacitance. There will therefore be
less variation as a result.

That's easy for you to say! :)


That is reflected in my results, but is
not the point I am making.

Having looked at your graphs again, I see that they are in fact totally
wrong.
Increased capacitance will actually *decrease* the HF response.
Hence why people found the V15III bright and harsh, because they had not
applied the correct capacitance load.

My graphs are wrong? They derive from my maths, which is shown as
well. If that is wrong, please show me the error - I'm always eager to
learn. If you are saying that while my calculations are correct, the
result is wrong, then I will have to ask you where Shure got
permission to abdicate from the real physical world.

What I am saying is, if you run a frequency reponse test using the gear
I mentioned in a previous post, and load the V15III with 250pF, the HF
will peak.
If you then increase the load to 450pF, the HF will flatten out.
This is the total opposite of what your graphs show.

Show me.

Well there you have me, I don't work for Shure any more, and I didn't
think I would ever have the need to keep the B & K pen recorder traces!!

History is on my side though, as all the Hi Fi mags of the day
complained about the bright top end of the V15III. After we pointed out
to them about the loading, it got much better reviews.

--
Kevin Seal
F800ST
{kevin at the hyphen seal hyphen house dot freeserve dot co dot uk}