balanced vs. unbalanced connections: how significant is the difference in sound quality?

[thin_ice]

This is something I have always wondered but never heard firsthand. I have only ever owned unbalanced gear but recently purchased an amp with both balanced and unbalanced inputs and was wondering if getting a balanced preamp would be worth it (I probably won't buy a balanced pre in the near term, but I can at least plant the seed). I know balanced signals run hotter and block out RF noise, but if one has a quality unbalanced preamp (and a quality amp that offers both connections), is the improvement in sound quality (of a similar sounding preamp but with balanced connections) of balanced connections really that noticeable? I definitely have heard differing levels of RF interference in different unbalanced interconnects and if balanced eliminates this altogether then I consider this pretty significant. Then again, some unbalanced cables do a darn good job of blocking out RF, but not completely (I think, the overall signal path is more than just interconnects). I've just never owned a balanced system to do the same tests for balanced. Has anyone who has owned a preamp and amp that offers both options compared the two? Also (for balanced, though Id guess the answer is the same for unbalanced) is the source>pre connection more important than the pre>amp connection? Or vice versa? From what I've gathered, the difference in sound quality is better for balanced, but how much? Are we just slightly more than splitting hairs or is the improvement in sound quality noticeably significant with balanced connections? Thanks!

 

[mfrench]

I do a lot of remote recording. In doing so, one of my rigs is an unbalanced rig. I very regularly run that rig with a single 50' XLR cable, that I've built ends for, that allow the single cable to be used as a stereo signal cable. I also run a pair of balanced mics/cables that require the same cable run, and, within the same area of the single stereo cable (often from the side wings, out to the center of the stage, at the stage-lip edge).
I've never noticed a difference in whether or not the signal has any degradation.

 

[thin_ice]

Im a bit confused, can you please clarify?

"one of my rigs is an unbalanced rig. I very regularly run that rig with a single 50' XLR cable, that I've built ends for, that allow the single cable to be used as a stereo signal cable. "

So is this "custom cable" considered balanced or unbalanced? (I think unbalanced). Are you saying you can or can't tell a difference bw balanced and unbalanced? (it sounds like you can't, not only that but for a 50' length of cable)

Thanks!

 

[mfrench]

The cables themselves are standard DIY XLR mono cables, built from Canare cable, with Neutrik ends. It is the terminations that are custom, to make a stereo cable from a single mono XLR cable. It is absolutely an unbalanced rig, when rigged this way.
This is one pair of those "custom" terminations that allow for that configuration:


The 1/8", 3.5mm stereo TRS connector, plugs into my unbalanced mic preamp that is on the stage with the mics. I'm "sending" a gain-added, amplified signal at that point. And, the two cable lead, with the RCA/1/4" pins is how I adapt into the recorder.

As mentioned, often times, I'll also run a balanced pair of mics at this same location. This requires two XLR cables, and is the classic balanced rig. So, I'll run three cables, one for the combined stereo signal of two mics, and the other with two cables/two mics, back to my location when utilizing these rigs.
Being two discrete stereo recordings from the four mics, there will always be a difference in how they sound, due to the different microphone types; one pair being omnidirectional, and the other directional. But I have never sensed a degraded signal in doing this.

 

[Olson_jr]

I tried this experiment when I had a Cary SLP-03 and a Bryson Power amp. Both units could be run single-ended or balanced.

I used sets of 2 Meter Kimber Heros for both the balanced and single-ended connections between the pre and amp.

Went back and forth several times in an afternoon, then I listened to each set up in place over several days.

I could not hear any difference between balanced or single-ended.

Tried the same thing with some PS Audio stuff recently and I initially thought the balanced sounded much better, like day and night better. Then I remembered that running balanced was giving me 3db more gain. When I accounted for the additional gain I could not detect a difference.

That being said, I think the braided Kimber Heros do a pretty good job of reducing or rejecting noise.

Obviously your mileage may vary.

 

[thin_ice]

Thanks and good stuff mfrench and Olson_jr!

I'm guessing the shielding on the Canares is excellent. Not like there should be much RF interference in a setting like that, but impressive nonetheless for a 50' run.

I am liking these firsthand experiences. Hopefully these results continue so money doesn't start burning a hole in my pocket.

 

[mfrench]

Yeah, the Canare cable has an intense shielding. It is thickly braided steel, completely surrounding the core wires (six wire leads, twisted into a Star-Quad twist; fancy words for spiraled).
I did have one occasion, 35 years ago, where I had picked up, literally, Mexican Radio, in a live recording. The concert hall was immediately next to a Cox Cable warehouse, with a large spread of satellite dishes across the rear of the building. Buried in the mostly acousitc concert was mariachis. But in thousands of live recordings, that is the only time I've gotten any form of EMI/RFI issues.
Here is another 50' run. What you cannot see is the second pair of mics, which were spaced across the center of the stage, and, taped to the inactive on-stage vocal monitors at the stage lip edge (the little black boxes wide left/right of center).

 

[mfrench]

Thanks and good stuff mfrench and Olson_jr!

I'm guessing the shielding on the Canares is excellent. Not like there should be much RF interference in a setting like that, but impressive nonetheless for a 50' run.

I am liking these firsthand experiences. Hopefully these results continue so money doesn't start burning a hole in my pocket.

Oh contraire....
There are endless possibilites, with things like wireless microphone transmitters, lighting controllers, AV systems for videos, cell phones (acckk!!), etc; I'm barely scratching at it. The worst offenders are the mic transmitter systems, and, especially *cell phones.

*My gear is all very well shielded, and I've never experienced a cell phone interference; but I've heard a huge amount about it, and seen the traces in the wav forms in peoples recordings.

 

[DC]

I had a similar curiousity and eventually expermented a bit to answer it for myself.

My CD player has both single-ended and balanced outputs, and my preamplifier has both in/out as well. (While the CD player is specifically a fully-balanced output circuit, and taps 1/2 of that signal for the single-ended output, my pre-amplifier is not a fully-balanced topography and uses transformers at the balanced inputs and outputs.) Anyway, I got the same make/model cables to compare: 1M set in RCA and 1M set in XLR. The difference was not subtle - the balanced signal was cleaner, quieter, and seemed (perhaps related to being cleaner and quieter) to have clearer resolution. The (significantly) blacker background helped the music "pop" right out. I did a quick return to the RCAs for a comparison, to verify what I thought I heard, and it didn't last long - I was a balanced convert in nearly an instant.

Going a step further, my amplifier is an actual balanced design, and has both balanced and single-ended inputs, with the RCA inputs routed through the XLR connectors on the back - you need to insert a short jumper pin in each XLR input to get the RCA input signal connected. Again, I got the same make/model cables: 3m RCA set and 3M XLR set. And again, the difference was not particularly subtle, cleaner and quieter, a significantly blacker background, and seemingly clearer resolution to the music. This time I didn't bother re-checking, the difference (and improvement) was just too obvious.

I can't say if the improvement from CD player to pre-amp or from pre-amp to amp was the better of the two - they were months apart - but their cumulative effect has been one of the best upgrades I've done in a while.

And I should clarify that things certainly weren't bad prior to switching to balanced cables - I had been enjoying the best sound in my system/room ever - it was just that much better again.

 

[mfrench]

The balanced rig gives you a hotter signal, by a substantial value (6dB? its been eons since I've kept track of this). That alone gives you a substantial presence boost that most will find to be a plus.
A drop in signal strength is a reason why I prefer to go unbalanced when I get a mixing board feed, as the drop in signal intensity is a lot easier to deal with when its coming at you live. Its enough to allow you to look professional rather than looking panicked, trying to turn everything down without messing with the recording.

 

[DC]

I should add that I did level-match my CD player cable comparisons. My preamp has input trimming capability, so I hooked the RCAs up to one input, the XLRs up to another, used a test CD and dB meter to measure the level, and trimmed them to match.

When I did the preamp-to-amp comparison, I was not as empirical about it, just got it close. The blacker background did it for me, levels notwithstanding.

 

[Thermionics]

I'll let you know when I hook up my Raspberry Pi MoOde player with the XLR outputs to my Drop THX AAA 789 headphone amp if it ever arrives...

 

[Try1256]

When I first got my BAT VK-3i preamp, I ran the single ended outputs to an Odyssey Khartago amp. Always had noise problems. When I got the BAT VK-200 and ran balanced all the way, no noise. Sounds great. I think a lot has to do with equipment synergy and compatible impedence levels.