Why moving coil
 

On Thu, 16 Mar 2006 19:08:27 -0000, "Serge Auckland"
wrote:

My question is why Moving Coils should be thought to be better than moving
magnets. I can think of several reasons why they should be worse, lower
compliance and higher mass, but not why they should be better. Trackability
should be better on a MM, as should record wear due to lower tracking
weights.

The quality of the stylus may be better on an expensive cartridge, but in my
own case, I have a Goldring 1042 and a Shure V15IIIMR. The stylus in the
Goldring is the Gyger S, I understand similar to the VdH, the Shure MR is a
Namiki profile, so they are as good as anything available on a moving coil.

Similarly, frequency response plots of moving magnets and moving coils don't
show any particular benefit to the MC, nor does stereo separation or
harmonic and intermodulation distortion. So why *are* MC cartridges throught
to be better?

If anyone knows of any good engineering reasons why this should be so, I
would be most interested to hear.

The only vaguely convincing explanation that I've heard is that MCs
can use less damping of the stylus assembly. Theoretically this
should allow better trackability at mid frequencies. I also have vague
recollections that the cantilever can more easily be made shorter,
which would help in keeping the effective tip mass down, which should
give better HF trackability. (Compliance only needs to be more than
about 10-12c.u. to track all records)

Not being a member of the MC owners club, I don't know if these
theories have any validity.

Bill

Why moving coil
 

AZ Nomad wrote:

On Thu, 16 Mar 2006 21:04:18 +0000, Nick Gorham wrote:



AZ Nomad wrote:


On Thu, 16 Mar 2006 20:18:11 +0000, Nick Gorham wrote:




Bret Ludwig wrote:


The moving coils are lighter but put out less energy than the moiving
magnets.



Voltage, maybe, but if you look at the source resistance of a MC, I am
not sure its less "energy".


energy too, but it's not as if your driving your speakers directly.
Fortunately we have an invention called the amplifier.



Yep, you are right, just compaired a Goldring MM and Ortofon MC, MM
about 3.5 times the energy out compaired to the MC.


I'm curious: what unit is that 'energy' measurement? Is it a power
measurement ie: microwatts, etc? I usually think of energy in joules,
power in jules/s or watts. I've never heard of anybody giving a ****
about a cartridges 'energy' measurement; just the voltage output
and recomended load capacitance.

Well, partly I was in pedantic mode with the original comment, but if
(as I do) you use a transformer to step up the voltage of the cartridge,
then it does have some bearing. The load impedance also is important not
just the capacitance. Most MC carts have such low generator resistance
that the capacitance makes little or no difference.

--
Nick

Why moving coil
 

"Bill Taylor" wrote in message
...
On Thu, 16 Mar 2006 19:08:27 -0000, "Serge Auckland"
wrote:

My question is why Moving Coils should be thought to be better than moving
magnets. I can think of several reasons why they should be worse, lower
compliance and higher mass, but not why they should be better.
Trackability
should be better on a MM, as should record wear due to lower tracking
weights.

The quality of the stylus may be better on an expensive cartridge, but in
my
own case, I have a Goldring 1042 and a Shure V15IIIMR. The stylus in the
Goldring is the Gyger S, I understand similar to the VdH, the Shure MR is
a
Namiki profile, so they are as good as anything available on a moving
coil.

Similarly, frequency response plots of moving magnets and moving coils
don't
show any particular benefit to the MC, nor does stereo separation or
harmonic and intermodulation distortion. So why *are* MC cartridges
throught
to be better?

If anyone knows of any good engineering reasons why this should be so, I
would be most interested to hear.

The only vaguely convincing explanation that I've heard is that MCs
can use less damping of the stylus assembly. Theoretically this
should allow better trackability at mid frequencies. I also have vague
recollections that the cantilever can more easily be made shorter,
which would help in keeping the effective tip mass down, which should
give better HF trackability. (Compliance only needs to be more than
about 10-12c.u. to track all records)

Not being a member of the MC owners club, I don't know if these
theories have any validity.

Bill

Interesting theories. Can you tell me a bit more as to why a compliance of
10-12cu is sufficient for all records? Interesting that in vinyl's heyday,
some cartridges were providing 30-40 cu. It could be a marketing exercise
rather than having a sound engineering reason for it, but it would be useful
to know why such high compliances are not necessary.

Thanks

S.

Why moving coil
 

"Serge Auckland" wrote in message
...
My question is why Moving Coils should be thought to be better than moving
magnets. I can think of several reasons why they should be worse, lower
compliance and higher mass, but not why they should be better.
Trackability should be better on a MM, as should record wear due to lower
tracking weights.

The quality of the stylus may be better on an expensive cartridge, but in
my own case, I have a Goldring 1042 and a Shure V15IIIMR. The stylus in
the Goldring is the Gyger S, I understand similar to the VdH, the Shure MR
is a Namiki profile, so they are as good as anything available on a moving
coil.

Similarly, frequency response plots of moving magnets and moving coils
don't show any particular benefit to the MC, nor does stereo separation or
harmonic and intermodulation distortion. So why *are* MC cartridges
throught to be better?

If anyone knows of any good engineering reasons why this should be so, I
would be most interested to hear.



I'm sure the replies have managed to cover all 'engineering' bases - I'll
just say that the MCs I've had have all sounded quite superb. (While they
lasted - I've lost count of how many I've busted now!!) One in particular
which had its very own 'poise' and an absolutely 'arresting' sound quality
was a numble Orto MC10 which I pulled the plastic off and ran nude. (The
cartridge....) That one was doomed when I got given it (bent cantilever) but
my goodness it was sweet while it lasted, right up 'til it finally gave
out!! (They come up on eBay from time to time and it's like Piranha on diced
beefstake when they do!!)

The 'cooking quality' cart I keep falling back to (for some odd reason) is
the Shure M75ED2 (original needles, naturally) - got one playing right this
minute!! About as subtle as a fart in a phone box but I can (and do) listen
to them all day long without any fatigue whatsoever!

Why moving coil
 

Trevor Wilson ventured

**Er, not quite. The FR plots of MC carts, in some cases, CAN be shown to be
superior. The reason, of course, is blindingly simple. It's all about
inductance. The inductance of (LOW OUTPUT) MC carts is very low, indeed. This
enables them to produce a very flat, very wide (up to around 60kHz) frequency
response, with a correspondingly superior rise time. The real benefit of such
a system is that LC resonance effects are often well outside the audible
range. This means that a low output MC cart may exhibit a very flat phase
response within the audio band. This may not be the case with high output MC
carts nor with some MM carts.

Are you sure "blindingly simple" makes sense?

I took the question to be general. Do you mean that it is obvious that MC has
less inductance than MM? Why is that please?

cheers, Ian

Why moving coil
 

Ian Bell wrote:

I am surprised there has been so little development of cartridges beyond the
two basic magnetic types and good old ceramic. What about an optical
cartridge for example?

Ian

I've wondered about that! If you take the electronics that is currently
used to read where a microsoft optical mouse is on its surface, give its
microcontroller a short sharp reprogramming session, and hang the whole
caboodle off a linear tracking arm, it would work?

University final year project for some lucky student reading this!

--
Adrian C

Why moving coil
 

In article , Serge Auckland wrote:
My question is why Moving Coils should be thought to be better than moving
magnets. I can think of several reasons why they should be worse, lower
compliance and higher mass, but not why they should be better. Trackability
should be better on a MM, as should record wear due to lower tracking
weights.

When they first appeared on the market they could easily be made out to be
better just because they were different so that they would sell. There are
plenty of people prepared to assume anything new and different must be better.

But that was a whole generation ago, and even then most people had stopped
worrying about such controversies as acoustic versus electric pickups,
clockwork versus electric motors, or steel versus fibre needles. In the 21st
century there's no need to worry about moving coils, magnets, or anything
mechanical, because now we just have moving light beams, or solid state memory
with no moving parts at all.

Rod.

Why moving coil
 

"Ian Iveson" wrote in message
. uk...
Trevor Wilson ventured

**Er, not quite. The FR plots of MC carts, in some cases, CAN be shown to
be superior. The reason, of course, is blindingly simple. It's all about
inductance. The inductance of (LOW OUTPUT) MC carts is very low, indeed.
This enables them to produce a very flat, very wide (up to around 60kHz)
frequency response, with a correspondingly superior rise time. The real
benefit of such a system is that LC resonance effects are often well
outside the audible range. This means that a low output MC cart may
exhibit a very flat phase response within the audio band. This may not be
the case with high output MC carts nor with some MM carts.

Are you sure "blindingly simple" makes sense?

I took the question to be general. Do you mean that it is obvious that MC
has less inductance than MM? Why is that please?

**MUCH less wire in the coils (to keep moving mass within reasonable
limits). High output MC carts negate many of these advantages.


--
Trevor Wilson
www.rageaudio.com.au

Why moving coil
 

"Ian Bell" wrote in message
news:4419d747.0@entanet...
Serge Auckland wrote:

My question is why Moving Coils should be thought to be better than
moving
magnets. I can think of several reasons why they should be worse, lower
compliance and higher mass, but not why they should be better.
Trackability should be better on a MM, as should record wear due to lower
tracking weights.


I am surprised there has been so little development of cartridges beyond
the
two basic magnetic types and good old ceramic. What about an optical
cartridge for example?

**Goodness me. There have been many different types of cartridges used over
the years, but, like internal combustion engines in automobiles, the
replacements don't offer the same advantages the tired old technology.


--
Trevor Wilson
www.rageaudio.com.au

Why moving coil
 

On Thu, 16 Mar 2006 21:21:59 +0000, Ian Bell wrote:


Serge Auckland wrote:

My question is why Moving Coils should be thought to be better than moving
magnets. I can think of several reasons why they should be worse, lower
compliance and higher mass, but not why they should be better.
Trackability should be better on a MM, as should record wear due to lower
tracking weights.


I am surprised there has been so little development of cartridges beyond the
two basic magnetic types and good old ceramic. What about an optical
cartridge for example?

Are you talking about bouncing a laser off the record groove? It was a failu
it was too expensive and worked worse than traditional methods as it was best
at reading the crud in the groove instead of just pushing it aside.