What's the benefit of balanced tonearm cables?

john_tracy

"He may have meant a balanced line with RCA termination. That is how I run my set-up. This presupposes that the RCA input of your phono pre is balanced ..."

Yes, this can certainly be done, and it's worth repeating because many audiophiles associate XLR connectors with balanced operation and RCA connectors as being always unbalanced. While that's often true, the truth is that it is the circuit - and not the connector - that defines whether or not a circuit is balanced.

In fact some phono preamps, including the ARC Ref Phono - which is a balanced, differential amplifier - offer only RCA connectors on the inputs. But provided that its RCA inputs are connected using a ground wire separate from the individual channel grounds, you'll have a fully balanced connection between a typical phono cartridge and the phono preamp. 

(I've omitted from this discussion the debate about how ARC grounds its balanced connections to the chassis. That a debate for another day. )

If your phono stage has XLR inputs, use XLR cables from cartridge to Phono stage.

Will you get dead silence?  Maybe!  Will the choice of XLR cable affect the sound?  Maybe?

I use RCA phono cables to my Pass XOno (which has RCA inputs only).  The choice of phono cable does affect the sound quality, however I always have dead silence!  No noise, with ear to speaker, and volume all the way up. 

The reason a balanced connection can have no cable artifact is the fact that the signal travels in a twisted pair within a shield (BTW this is how the signal travels in the tone arm- the arm itself being the shield).

The shield is there for shielding and does not have anything at all to do with the signal otherwise. The signal occurs in the twisted pair- the output of one is in respect to the other, rather than ground which is the shield.

In a single-ended setup, the minus output of the cartridge becomes the shield. In this way signal current is passed through the shield and is vulnerable to noise issues. Usually these manifest as intermodulations (colorations) rather than actual hiss or buzz.

(If an RCA is used as a balanced connection, which is dicey due to the grounding scheme, the result is that it will be prone to noise pickup because of the imbalanced introduced by the connector itself. If you doubt me, just touch the shield connection of the RCA on the preamp and see what you hear. BTW if you hear nothing then its not being used in the balanced mode- this is why I say you either have balanced or you don't and there are no in-betweens.)

This is why a balanced line interconnect can be rather inexpensive and will easily keep up with the most expensive single-ended cable no worries. There are of course other advantages, some of which have been discussed here. There really is no advantage to running single-ended in this situation, keeping in mind we are talking about how the cable behaves and not really how the phono section behaves, although its a fact that a fully differential balanced phono section has advantages too.

Conclusions:
all cartridges are balanced.
the cable thus can be inexpensive.
the cost of the cable is part of the cost of the system.
So balanced line can actually be less expensive, quieter and less colored than a single-ended setup.
Again this is so far just about the cable and its advantages. This is not about the behavior of the preamp, although that certainly plays a role- perhaps a topic for another thread?

If an RCA is used as a balanced connection, which is dicey due to the grounding scheme, the result is that it will be prone to noise pickup because of the imbalanced introduced by the connector itself.

IME using a RCA plug to terminate a balanced phono line (twisted pair with separately grounded shield) is not as problematic as you suggest. In an ideal world one would want to use XLRs. Where that isn't practical using a RCA termination won't be the end of the world. I am assuming the RCA jack connects to a "floating" transformer winding or a true diff. input.

I can clearly hear the differences in balanced cable....are you saying that balanced cables sound alike?