What's the benefit of balanced tonearm cables?


My phone stage (bat vkp10) has xlr and rca inputs. bat vk50se preamp. I use all balanced cables for everything except the tonearm cable.

What's the benefit between your cartrige to phone stage?

Thanks!
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I can only answer your question in theory, since it would take actual listening to tell if there is an audible difference in your system between a balanced and unbalanced cable.

Balanced cables are normally recommended for situations where you need to carry a weak signal over a substantial distance. Here are two examples where a balanced cable is probably desirable:
1. carrying a relatively low-voltage audio signal from a microphone to a recording device that is 30' or more away;
2. sending a signal from a preamp to a power amp that is 15' or more from the preamp.

If the distance from your tonearm to your phono stage / preamp input is less than 5-6 feet, it is unlikely that you really NEED a balanced cable. Infact, some audiophiles (including members of this forum) state they prefer the audio quality of unbalanced RCA cables to balanced XLR cables. To determine for yourself, you will have to do some extended comparisons.
A phono cartridge is by nature of the design a balanced source to begin with. If you're lucky enough to have a phono stage with balanced inputs then by all means do take advantage! The benefit over unbalanced is reduction in hum & noise pickup via significantly better common mode rejection ratio.
Or pseudo balanced rca as apparently my arm cables are. I have no idea what anyone is saying! I asked a techie and he said a cartridge can only be left and right so not balanced and the arm guy responded and said my arms are pseudo balanced, so pretty well nearly fully balanced. As I have no way of comparing or altering it is yet another one of those wierd techie issues that drive us normal people to distraction if we stop long enough to wonder what they are all saying.
The reason you go with balanced line is to eliminate any cable artifact, and by that I mean that you may have noticed that some cables sound better than others. That goes away with a properly set up balanced line system.

Balanced line and single-ended (RCA connections) are inherently incompatible. If you have one then its not the other. There is no such thing as pseudo balanced- that would simply be single-ended.

Now all phono cartridges happen to be balanced sources. Anyone saying otherwise is simply misinformed. The coils of the cartridge will work fine if they are hooked up backwards- all that happens is they are out of phase. If you did that with a single-ended source like a tuner you would get a huge buzz.

You know that little ground wire connection that most tone arms have? The one that other single-ended sources don't seem to need? That is there there to deal with the fact that a balanced source has a ground connection that is independent of the signal. Without it the balanced source, run as a single-ended source, will buzz. Its easy to hook up a cartridge in the balanced mode- in most cases you don't do anything with the tone arm wiring. Its usually about the interconnect cable that goes between the arm and the preamp. To do this, the preamp really does in fact have to have a balanced input.

The advantage of doing this is that the interconnect cable at the source of the stereo will not have any effect on the sound of the system. If you used a single-ended setup, the cable would have an effect and would have to be chosen with some care.
I've never heard of blanced cabled cancelling cable artifacts. What they DO measurably do is reject common mode noise.  EMI/RFI is often like that.  It induces a current in the same direction in both conductors which cancel each other out.

They may also have increased capacitance or inductance as a result of the construction.

For a tonearm, it's very interesting, since most cartridges are inherently balanced, using a balanced input stage could lead to less noise pick up, and better detail retreival.  COULD. No idea if true.
I use balanced (XLR) connections from the cartridge, through the pre, through the amp.  ....I can put my ear to the speaker cones on phono input and hear nothing...dead silence.  This contributes to the clarity/definition, and transparent listen experience.
erik_squires
"I've never heard of blanced cabled cancelling cable artifacts."
It's not the balanced cabling so much, as using balanced connections into a differential amplifier. By definition, a differential amp should negate any effect of the cable.

Balanced line and single-ended (RCA connections) are inherently incompatible. If you have one then its not the other. There is no such thing as pseudo balanced- that would simply be single-ended.

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. In my case, with a transformer input, the XLR and RCA inputs are connected in parallel with a ground lift switch. Lifting the ground converts the RCA input to balanced. One could argue that the asymmetry of the RCA connection would introduce some differential noise. I would argue that the effect would be small at best.

My reason for this arrangement is convenience. I have a Rega style tonearm where the cables exit the mounting post and have to fit through the hole in the arm pod on my Nott. TT. Not keen to unsolder and solder XLRs every time I have to pull the tonearm.


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?
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.

Balanced signals have greatly reduced common mode noise, but that’s not what I would call a cable artifact, so much as atmospheric, or environmental.

What they can completely eliminate is ground loop contamination, and crosstalk.  Cross talk COULD Be caused by a non-zero ohm ground.

So three things:

  • Improved common-mode noise rejection
  • Eliminated ground loop
  • Reduced L to R cross talk

But eliminate cable effects? That’s a bit of a stretch for me. It does not cancel out capacitance, inductance or resistance. 



Best,


Erik
This might be a little off topic.
I'd like to make a statement, and Ralph is probably the only one that can comment on it.

Let's look at the waveform coming from the cartridge. Because it is a balanced source, it looks like a pure Sine Wave. We can all envision this, because we've all seen it.

Pin 2 of the XLR carries the positive (rising) portion of the sine wave, while pin 3 carries the negative (falling) portion of the sine wave. A dual differential circuit amplifies both halves of the waveform. Eventually the positive portion pushes your driver 'out', while the negative portion pulls your driver 'in'. We get pure sound.

In an RCA connection, the center pin carries the positive portion of the waveform. Your driver moves out. But what happens to the negative portion. This is now referenced to ground. Ground can be envisioned as the center of the waveform, meaning the driver is only pulled halfway down. For all I can tell, the rest of the negative portion of the waveform is 'thrown away'. My question is: what is pulling the driver all the way back in?.

If you have a dual differential amplification chain, stay with XLR. The entire waveform will be preserved, at least until it reaches your 'unbalanced' parallel speaker crossover. 
I can clearly hear the differences in balanced cable....are you saying that balanced cables sound alike?
They will if set up correctly. You might want to take a look at the Audio Engineering Society file 48 which defines the balanced line standard. I the shield gets driven by the source you will experience cable artifact- IOW various cables will sound different, although not nearly as much as with single-ended setups.
But eliminate cable effects? That’s a bit of a stretch for me. It does not cancel out capacitance, inductance or resistance.
Its not a matter of cancellation- its a matter of reduced IMD and swamped cable artifact due to low impedance operation. In the case of a phono cartridge, the source impedance is quite low, maybe only a few ohms, often terminated at the other end by a low impedance as well. Its hard for a cable to express any artifact of capacitance or inductance in such circumstances.


your bat gear is a balanced design and would benefit from balanced cables. Many companies simply provide the option for balanced or single- ended at the rear to accommodate customers (pseudo or fake). generally a balanced design will sound better running balanced cables-my gear has always been single-ended and sounds better that way. many of my friends talk about the increase in volume they get with balanced but do not focus of the sound quality difference if any. it was originally designed for longer runs in studios etc.
From the phono amp designers I have spoken to over the years it's not a simple case of one design being better than the other, but a question of implementation.
I recall one designer saying that he gave a balanced option to satisfy the demands of the high end buyers i nthe states and far east. He said that introducing the extra circuitry for the grounding in a balanced set up caused of itself problems, and wrongly done can cause sound.
Two of the greatest stages of all time were un-balanced - Vendetta and Mares/Connoisseur.
Balanced signals have greatly reduced common mode noise,

Just to be precise, balanced signals can have common mode noise, maybe even a lot. It's that balanced circuits reject the common mode noise and only amplify the differential signal.