balanced vs unbalanced output


Can anyone explain difference (technical or in sound quality) b/w balanced and unbalanced outputs? Is the image clearer on balanced? Thanks
aarif
The primary benefit of balanced connections is reduced noise. Correct balance cancels any noise riding along with the signal.

Sometimes, depending on the circuit, you may also get higher gain.

Sound quality with this lower noise floor you get better detail retrieval which helps soundstaging to.

BUT !! Balanced doesn't always equal better sound. It depends on the equipment, the circuit design, etc etc...don't assume balanced is better. It's not black and white...
Also be aware that not all equipment with an XLR connector has true balanced circuitry. That should be verified with manufacturer
As an added note, balanced interconnections are more commonly used in professional environments. The reason is that equipment is located all over the place and you might have a long run of wiring, say a 75' microphone cable. A unbalanced cable of this length would be much more subject to noise pickup. A true balanced circuit has a high "common mode rejection ratio" that makes it much quieter with long cable runs or in a noisy EMI environment.

Most home systems don't have these problems to the same extent so the primary advantage of a balanced mode isn't as big an issue. That is not to say you will not hear a difference between the two connections. However, it could turn out that you might prefer the unbalanced connection. The only way to find out is to try your setup both ways.

If you currently don't have equipment that offers a balanced connection it is not something I'd lose any sleep over if you like the way your system sounds.
Assuming a differental input on the receiving end, balanced is a superior choice and there is no technical reason to not take advantage of it.

But, no one knows whether one or the other is sonically more pleasing to you.
Assuming a differental input on the receiving end, balanced is a superior choice and there is no technical reason to not take advantage of it.
There are those who might argue a bit with that statement. A differential circuit, by definition, is more complex than an unbalanced one. Some designers believe simplicity and a reduced parts count benefits their design sonically. They would argue that a balanced circuit helps with a specific type of noise issue, and, if your equipment is not going to be used in an environment which has that problem, why complicate the circuit?

I've got a Lavry DA-10 DAC with balanced outputs. I recently switched from an amp with balanced inputs (which I was using) to a different amp that only has unbalanced inputs. It made zero difference in the background noise. With either amp I could put my ear directly to a speaker and hear no noise. Specification-wise the old amp had a 20% better S/N ratio but there is no audible noise difference between them in use.

That is a good example of a home situation where the balanced/unbalanced issue is irrelevant in contrast to other attributes.
Martin Colloms has tested large numbers of both balanced and unbalanced and has found that in 95% of the cases the unbalanced sounds better. See current thread in the HIFICRITIC forum.
Sonically I agree with Stanwall, but the connectino is better with XLR connectors due to the size variation in RCA connectors. Thus, I like to use pin 1, the gnd, and pin 2(+) and avoid pin 3 (-) and connect with XLR, and avoid the problems with RCA connectors, and get the benefits of an XLR. A hybrid of sorts with RCA sound and XLR connections....works for me. I use balanced for long runs if noise is an issue. JALLEN
I certainly have a lot of respect for Martin Colloms, but there is a problem with such a generalized comparison.

If you are comparing the balanced vs unbalanced inputs on the same piece of equipment, you've got a very high probability that the unbalanced circuit is already disadvantaged with the extra circuit complexity needed for the balanced design. Not many designers are going to build two separate inputs circuits on a device.

If you are comparing a piece of equipment with balanced inputs against a different piece of equipment that has only an unbalanced input, you are comparing a myriad of other variables besides that one factor.

When I searched for the article, the very first sentence of the very first comment that came up said: "I found this article too full of caveats to make the argument for balanced connections" and it then referred to the cheap integrated circuits some equipment uses to make a balanced connection but keep cost down.

So we are back to how the circuit is implemented in a specific design. If you love the sound of your favorite preamp or amp and it lacks balanced inputs, I'd say it is not worth obsessing about.
If you are comparing the balanced vs unbalanced inputs on the same piece of equipment, you've got a very high probability that the unbalanced circuit is already disadvantaged with the extra circuit complexity needed for the balanced design. Not many designers are going to build two separate inputs circuits on a device.

Assuming the amp is an unbalanced design and the inputs are switched, I don't see how the differential input will have any bearing on the unbalanced input.

From what I've read the unbalanced input should have an active buffer whose output I assume will tie in at a common point after the differential input.

I don't see how it's all that relevant whether the differential input is constructed from discrete transistors or single op amp chip. The key to its effectiveness is impedance matching.

There's is also an IC available that matches transformer based balanced inputs: http://www.jensen-transformers.com/an/ingenaes.pdf and http://www.thatcorp.com/1200-series_High_CMRR_Balanced_Line_Receiver_ICs.html
I'm trying hard not to have a debate about this subject, but rather to point out that a balanced design is not the end-all, be-all for home equipment. There are designers who prefer unbalanced; it took only a few clicks to find that the designer for the pricey Manley Labs equipment prefers unbalanced design as do Conrad Johnson and some others.

There are other designers who prefer balanced and still others who just go with the flow since balanced home equipment is more popular these days than in the past.

I've had equipment that runs both ways. I'd much rather have my current unbalanced amp than say a $200 Behringer with balanced inputs.

My only point? Absent a specific need for the common mode rejection capabilities of balanced circuitry, this spec is toward the bottom of the list of concerns for a typical audiophile when picking a piece of equipment. T'ain't no more complicated than that.
Mlsstl, I don't want to debate anything.

I agree completely that one can put together a satisfying system using unbalanced interfaces.

Balanced interfaces provide better signal transmission and, as I stated originally, there are no "technical" reasons for not taking advantage of them.

For me balanced lines are like an insurance policy. I may not need it today, but who knows down the road as things change. Thus, balanced lines are a top priority for me when selecting gear.
Bob - you said it right. It is a kind of insurance against noise and there is no reason they should sound worse (other than shield unfortunately grounded on both ends). My Rowland class D amp doesn't even have unbalanced input - very mature on Jeff Rowland side in presence of class D introduced electrical noise.
While you state there are "no 'technical' reasons" against balanced design, I would simply comment again there are some talented designers of well-regarded equipment who apparently are not in full agreement with that statement. They state their case better than I, but at least it makes the point there is not a universal consensus on the subject.

Some designers don't want the added transformer or differential amp needed for balanced. Here's a comment by Robert Harley of Absolute Sound:
The preamplifier's balanced output is then sent from the preamplifier output to the power amplifier's balanced input where it's-that's right-converted to unbalanced with yet another active stage. The result of these unbalanced/balanced/unbalanced/balanced/unbalanced conversions is additional electronics in the signal path-just what we don't want. This is why you can't assume that balanced components sound inherently better than unbalanced ones.

My observation is there are many areas of science and engineering where there is more than one opinion about the best approach to an issue. Building anything involves compromises and choices where different people arrive at different conclusions. Audio is not an exception.

Thanks for an enjoyable discussion.
This is just like watching "Rocky"
Dreadhead - I'm not sure why you're bringing Rocky into this.

Mlsstl - when I mentioned no technical reasons I was thinking of cable alone. You are right - there are some shortcomings of balanced like distortions caused by transformer at lower frequencies or additional component (instrumentation amp) in the chain. Balanced can be grounded at the input, of course, but it defies the purpose of the balanced cable.
Mlsstl, thank you for keeping the discourse civil.

It seems reasonable that in the early years, before digital and wireless, that unbalanced interfaces were quite adequate for home environments. I think the recent trend towards more home components supporting balanced interfaces is an acknowlegement that today's home environment has changed.

Also, it wasn't mentioned in the paragraph you quoted by Harley that an unbalanced input will also go through an active stage to buffer the input. For an unbalanced amp design, the same active stage can be used for both balanced and unbalanced inputs. See the Bryston 4B SST as an example.

All the best.
Hey Dreadhead... How did you know I was wearing all my gold chains! Pity the fool! :-) http://en.wikiquote.org/wiki/Mr._T
i wonder if there is any point if one component has a balanced output and the amp does not have any balanced input .I was advised there is a balanced rca adaptor that can be used to connect .Does this defeat the purpose?
Valverocks wrote: "i wonder if there is any point if one component has a balanced output and the amp does not have any balanced input .I was advised there is a balanced rca adaptor that can be used to connect .Does this defeat the purpose?"
In this setup you will not be able to take advantage of "common mode rejection" that can reduce noise. You will also not have the extra 6 dB gain typically seen in a true balanced design.

However, the output connector is different and your wire construction until you get to the RCA adapter is also different, so it is possible you might like the effect that offers. However, the two "big" technical advantages of a balanced line will not be present if you use a RCA adapter.