"Patrick Turner" wrote in message
...


Serge Auckland wrote:

"Jim Lesurf" wrote in message
...
In article , Dave Plowman (News)
wrote:
In article , Iain
Churches wrote:
A four pin miniature Tuchel is a good connector for a balanced phono
cartridge. I have sen them used on several occasions in this
application.

Aren't all phono cartridges - apart from Decca - effectively balanced?

Do any of them include an electrostatic screen linked to one of the
leads?
I can't recall any, but the above makes me wonder.

Slainte,

Jim

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The Shure V15II and III have a little brass tag which links the can to
the
left ground connection. If the arm has a metal headshell and continuity
to
the arm ground wire, then the tag can (should?) be removed. Without the
tag,
the cartridge is then balanced. I don't know about other makes of
cartridge,
they could well have the can bonded to one pin, in which case they would
then be unbalanced, or rely on the headshell, in which case they would be
balanced. MC cartridges, which don't have any screening usually, would be
balanced devices.

Your'e not distinguishing the difference between balanced and floating.

You might use a floating winding that has no part of it directly
connected to a ground anywhere
to make a balanced connection with an R divider at an amp.

Balanced does not always give better hi-fi.

And balanced was first used in telephones, to reduce noise over long
distances.
Twisted pairs and common mode rejection etc.

It makes little difference to noise over 2 metres if you know how to rig
a normal
unbalanced phono input.

Patrick Turner.



I'm referring to the common Hi-Fi practice of taking a cartridge, which,
agreed is normally floating, into an unbalanced input. The floating
cartridge is also usually pretty well balanced, especially in the case of
moving-coils. Moving Magnets may not be quite so well balanced as the
physical size of the coils will often make one end of coils nearer the
screening can than the other, but nevertheless, they can be considered as
balanced, floating devices for practical purposes. - Try centre-tapped
terminating the coils, and taking the output between the centre-tap and
screening can to see the out-of-balance. I would suggest it will be very
low, and confined to very high-frequencies as the unbalance will be
capacitative.

I fully agree that balance doesn't necessarily give better hi-fi, but as
with microphone circuits, it's good practice to balance low-level signals
where this is possible. Given that a cartridge is essentially a balanced
device, I would have thought that the High-End Audiophool community would
have latched on to balanced phono circuits, rather than the rather less
beneficial balanced CD inputs, or pre-power amp links. It goes to show that
the HEAP community hasn't the first idea of engineering principles.

S.



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