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}