Balanced versus Unbalanced Connections

Robert Katz 5 Comments

Why some mastering engineers insist on using unbalanced lines…

Do any of the engineers on the list use balanced interfaces at all?

>Balanced is for Mics and Telephones, wrote Dave Collins of A&M Mastering on the mastering list!

and I replied

It’s nice to meet with another engineer who subscribes to that. All other things being equal, unbalanced is better. Now just what does that mean? Well, basically, it boils down to the “less is more” philosophy.

Here are the caveats: In a small room, where all the power is coming from a central source, and all the analog gear is plugged into that power and no analog audio enters or leaves the room, and you have your signal to noise and headroom issues all straightened out, then unbalanced is almost always better sounding than balanced.

Exceptions: a) Equipment whose balanced stages are so-well-designed that it is impossible to design the same piece of gear with fewer stages unbalanced than the balanced version. b) Equipment which has completely balanced topology throughout, fully mirror imaged in its inherent design, and impeccably designed with the best components (example, Nelson Pass gear). But I’m not so sure it sounds better because it’s balanced or just because it’s better! I’ve removed 5 op amps from the front end of a certain well-known A/D converter, and removed 5 veils from the sound. Think about that. I’ve removed 3 tubes and an output transformer and several relays and resistor networks from the output stage of my Ampex MR-70 electronics, and been rewarded with “more tight,” definitely quieter and more transparent sound.

Comments 5

  1. Hello,
    I’m trying to wrap my head around the way you are wiring the interconnects to use balanced outputs and inputs in an unbalanced fashion. I understand the reasoning behind it as it bypasses some balancing stages inside some circuits and I’d be very interested in trying this for myself. I’ve read a post from many years ago describing how you wired a Benchmark to a Cranesong Trakker and was curious as to how the cable would be wired, as it seems to be a bit different approach than driving pin 3 from the unbalanced ground/shield scenario I’m familiar with. You did mention grounding the Trakker’s pin 3 at the input and that’s where I’m unclear. So,to give one scenario, if using a 2 conductor wire with additional shield, the positive conductor to the female xlr at the balanced output would go to pin 2 and the negative conductor to the same female xlr would go to pin 1 with pin 3 left unconnected. Then the positive conductor would be connected at pin 2 of the xlrm at the balanced input, the negative conductor would go to pin one of the xlrm. When you say to ground pin 3, how exactly is that happening? Are you saying that you tie the negative to pins 1 and 3 at the balanced input? Or are you connecting it some other way? Sorry if this seems like I’m missing the obvious, I’ve just been familiar with making unbalanced work with balanced and vice versa. On a side note, I understand you mentioned from this past post that the Trakkers don’t really need the benefit of this scheme and I’m not asking for this reason. I don’t own any Cranesong gear…Yet…..

    Thanks so Much!
    Scott
    Orlando,FL

  2. Hello,
    After taking a minute or several more to think about it, I think I understand the wiring to make everything work as to be unbalanced. I was for some reason not catching that, once an output is unbalanced by floating pin 3, it’s actually feeding a balanced input still but with an unbalanced signal. The Rane notes were throwing me off a bit by only showing one conductor wire being used from balanced to unbalanced and only 2 conductor wire being shown for unbalanced to balanced. But, since it’s really going to be unbalanced outputs to balanced inputs, using 2 conductor wire, you’d leave the shield floating and pin 3 not connected at the output and tie the shield to pin one at the input … So simple it’s complex? One question just to clarify the above correspondence; when you mention removing 5 op amps, etc. from the converter and the various other networks from other gear, you’re simply implying that, by unbalancing the input and outputs, these additional stages are being bypassed correct? Or are you speaking of actual mods?

    Thanks!

  3. Post
    Author

    Dear Scott: Thanks for writing. Before unbalancing any balanced output, it is very important to check with the designer of the gear to find out the best way to unbalance it. In some cases grounding one pin introduces distortion. In some cases just using one hot pin and ground produces a poor, thin signal as the stage emulates very well the characteristic of a transformer. I would not float the shield. I would connect the shield between the two pieces of gear. As I said, opening pin 3 on the source could work and be the best solution (though 6 dB down of course), but not if the stage emulates a transformer. Hope this helps,

    bob

  4. Thanks! I was speaking of active balanced outputs as I would just leave any transformer or cross coupled outputs be. I think leaving the shield disconnected at the output and connecting it to pin one on the following input would work in the case of active balanced? Very neat information. I was hoping this would be an interesting experiment for some gain staging ideas I have to.Thanks again!

    Scott

  5. Oh boy..Maybe I’m rushing into it..Judging from the quick reading in some of the AES info I guess I have some serious reading ahead of me. Hello Pandora! What’s in the box there?
    What in the world has been going on with this stuff? I’m really hoping that I’m over thinking everything but, much of the information, that is quite old in fact, is news to me…

    Thanks again!

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