Balanced Vs. RCA

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Harmon

Balanced Vs. RCA
« on: 20 Feb 2004, 12:39 am »
Hey guys does balanced components sound better than RCA or vice versa? Or is there no difference. Or does it depend on the quality of the component itself? Thanks

JoshK

Re: Balanced Vs. RCA
« Reply #1 on: 20 Feb 2004, 12:52 am »
Quote from: Harmon
Hey guys does balanced components sound better than RCA or vice versa? Or is there no difference. Or does it depend on the quality of the component itself? Thanks


the later...  remember balanced is twice as much circuitry and thus twice as expensive for a given level.  Balanced probably does have inherent advantages (i am going on theory here) but if lesser parts or circuitry is used I doubt the advantages are reaped to yield better results.

PhilNYC

Balanced Vs. RCA
« Reply #2 on: 20 Feb 2004, 01:17 am »
If you are talking about component design being balanced or single-ended, Josh is correct...a lot has to do with the specifics of the component (design, parts, etc).  But you asked "balanced vs. RCA", which implies that part of your question has to do with cables...and there are very specific instances where balanced cables do have distinct advantages over a single-ended/RCA version of the same cable; specifically in long cable runs where the opportunity to pick up noise in the cable is relatively high, using balanced cables to reject noise is IMHO more desireable....

JoshK

Balanced Vs. RCA
« Reply #3 on: 20 Feb 2004, 01:26 am »
Not to pick on you Phil but my understanding of the cable design, as far as balanced vs. RCA assuming the circuitry is single ended so that the balanced cables don't have an advantage in utilization, is that balanced can have an advantage, but it depends.   (how is that for a run on sentence?)  Noise rejection?  I don't think so, noise rejection is more to do with geometry and the termination wouldn't have as much to do with this.  Noise cancelation?  That depends on whether the circuitry you are connecting to is inherintly balanced or not.  Balanced circuitry will provide noise cancelation by comparing the neutral to hot and rejecting the noise.  

I think Phil and I are on the same page and the difference is semantics.

TheChairGuy

Re: Balanced Vs. RCA
« Reply #4 on: 20 Feb 2004, 01:30 am »
Quote from: Harmon
Hey guys does balanced components sound better than RCA or vice versa? Or is there no difference. Or does it depend on the quality of the component itself? Thanks


I've wondered the differences of these, too.....thanks JoshK and Phil for phil-ling me in on the differences (semantics aside) :thumb:

Kevin P

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Balanced Vs. RCA
« Reply #5 on: 20 Feb 2004, 01:30 am »
If your equipment isn't designed for true balanced operation from source to amplification it is pretty much just bragging rights.  Even if all your equipment is capable of true balanced (some just convert the XLR input to single-ended operation inside the chassis) then it really only is beneficial with long cable runs.   That is why they are so popular in pro-audio where long cable runs are the norm.

eico1

Balanced Vs. RCA
« Reply #6 on: 20 Feb 2004, 03:51 am »
I think the main benefit a balanced interface is the ground isolation it provides. That will clear up the audible noise floor more than any cable rejection etc.

I don't understand why converting a balance input to single ended within the amplification matters negates anything though. Sounds like an old tale.

steve

Tonto Yoder

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Balanced Vs. RCA
« Reply #7 on: 20 Feb 2004, 04:29 am »
Link to an old Stereophile article ("Balance: Benefit or Bluff"):

http://www.stereophile.com/features/335/

PhilNYC

Balanced Vs. RCA
« Reply #8 on: 20 Feb 2004, 12:32 pm »
Quote from: JoshK
Noise rejection?  I don't think so, noise rejection is more to do with geometry and the termination wouldn't have as much to do with this.  Noise cancelation?  That depends on whether the circuitry you are connecting ...


I had always heard that the whole point of using balanced cables was the common mode noise rejection it provides (the two hot wires carry mirrored signals 180 degrees out of phase with each other relative to ground, then any noise that is in-phase at the end of the cable is rejected).  Seems like every time I've had this dicussion with people, the general consensus is "use balanced for long cable runs because the cables can pick up noise".  Is this not true?  This would be like someone telling the the Easter Bunny isn't real... :o

_scotty_

Balanced Vs. RCA
« Reply #9 on: 20 Feb 2004, 12:37 pm »
For those that are interested read the the articles contained in these links on
CMMR and balanced inputs.  http://www.proav.de/index.html?http&&&www.proav.de/data/commonmode.html
http://www.benchmarkmedia.com/appnotes-a/caig/caig04.asp

These two articles explain that balanced lines require a true differential input to have any merit. If the input stage is single ended and the balanced line is converted to single ended upon it's arrival at the input stage no
common mode rejection of noise common to both halves of the signal phase occurs.  You may be sleeping better but you have gained nothing in the way of lowering the noise floor in your stereo,and you have added expense
and complexity to your cabling equation.

PhilNYC

Balanced Vs. RCA
« Reply #10 on: 20 Feb 2004, 12:43 pm »
Btw - I did understand that the CMR took place at the input of a component (say, for example, an amp).  But the entire amp doesn't need to be balanced for it to do this....

DVV

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Balanced Vs. RCA
« Reply #11 on: 20 Feb 2004, 07:31 pm »
Balanced cables reject noise better than standard cables; this is why they are almost mandatory on longer runs. What is "longer"? You'll get as many answers as the number of people you ask, and to me, "longer" is anything than about 3 m (6.6 ft). This can be demonstrated quite easily using a microphone - at say 4 m runs (13 ft), standard cable will almost surely produce microphony, whereas a balanced cable will not.

However, regarding the signal transfer, my experience is that balanced is really going overboard unless the input of the subsequent stage is not fully differential, meaning that it requires both polarities at its input for proper operation.

In most cases, an XLR connector is offered, but behind it sit yet more electronics which convert unbalanced to balanced or vice versa. While this is quite possible to do, it is far from easy to do it well, and typical solutions use just one op amp for the job, and that all too often of doubtful sonic quality, but of undoubted economic merits for the manufacturer.

Also, using fully balanced implies a floating ground, and this in itself is VERY hard to do well. I have seen only a few designs which had this done really well, most are for show only and if you dig down deep enough, you might evetually find this to be a simple, old fashoned hoax (specific names ommitted on purpose here).

My experiments, and I readily admit they are far from being conclusive, show that the best method yet is to filter the ground and stay with classic single ended inputs. Noise decreases by 7-9 dB (up to 12 dB in one case), which is more than with balanced, and at zero cost in circuit complexity. This is why I use this approach, but do not claim it to be the ultimate solution.

Some years ago, while I was still working on TV, we compared the sonic results between the two by connecting a Studer CD player to a professional Sony mixer console first with unbalanced and then with balanced. We could switch from one to another with a flick of one switch. After 2-3 hours, 5 of us agreed that we couldn't hear any differences using Klein & Hummel active 3 way speakers (12" bass, 5" dome mid, 3/4" dome tweeter) because we couldn't get anywhere near statistical significance in the blind tests we conducted.

In my view, for home audio, XLR's literally only advantage are the truly superior connectors themselves.

Cheers,
DVV

Psychicanimal

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Balanced Vs. RCA
« Reply #12 on: 20 Feb 2004, 09:16 pm »
Quote from: DVV


My experiments, and I readily admit they are far from being conclusive, show that the best method yet is to filter the ground and stay with classic single ended inputs.

In my view, for home audio, XLR's literally only advantage are the truly superior connectors themselves.



Had to be the Serbian hope... :lol:

witchdoctor

Balanced Vs. RCA
« Reply #13 on: 20 Feb 2004, 09:59 pm »
In my system I went from 1 meter Bodan Silver Spirit RCA to 1 meter Bogdan Silver Spirit XLR from my Sunfire TG3 to the amps in my front 3 active speakers. It was 300% better, no contest!

Psychicanimal

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Balanced Vs. RCA
« Reply #14 on: 20 Feb 2004, 10:50 pm »
Quote from: witchdoctor
In my system I went from 1 meter Bodan Silver Spirit RCA to 1 meter Bogdan Silver Spirit XLR from my Sunfire TG3 to the amps in my front 3 active speakers. It was 300% better, no contest!


Like the Serbian Hope said, you might not have properly aaddressed ground noise control...

witchdoctor

Balanced Vs. RCA
« Reply #15 on: 20 Feb 2004, 10:57 pm »
Good point, how would I know if it's been addressed?

Psychicanimal

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Balanced Vs. RCA
« Reply #16 on: 21 Feb 2004, 12:25 am »
Quote from: witchdoctor
Good point, how would I know if it's been addressed?


My system runs off a 220V/110V ONEAC islation transformer/filter w/ a patented "Virtual ground" feature which isolates the building's ground from the stuff plugged to the transformer.  My system is real quiet.

witchdoctor

Balanced Vs. RCA
« Reply #17 on: 21 Feb 2004, 02:10 am »
Will it work in an apt?
Where do I get it?

_scotty_

Balanced Vs. RCA
« Reply #18 on: 21 Feb 2004, 03:50 am »
If I am not mistaken, a balanced power isolation transformer provides a "virtual ground" because the center tap on the secondary acts as the ground and there is no actual connection to earth ground by the equipment plugged into it. Theoretically any balanced power isolation transformer could provide a ground not referenced to earth ground.

DVV

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Balanced Vs. RCA
« Reply #19 on: 21 Feb 2004, 07:29 am »
Quote from: _scotty_
If I am not mistaken, a balanced power isolation transformer provides a "virtual ground" because the center tap on the secondary acts as the ground and there is no actual connection to earth ground by the equipment plugged into it. Theoretically any balanced power isolation transformer could provide a ground not referenced to earth ground.


Quite so. However, that does leave you wondering how much of the theory has actually been applied.

Of course, one is always left to wonder with anything, but in this case, you have two things to worry about rather than one: 1) how well has the whole thing been designed and executed, and 2) what does it specifically do to your ground?

Do not underestimate the ground games. Remember, any and all electronic products need it for very critical applications, from power supply rail filtering and stabilization, to feedback control and reference points. Shift the ground and you shift everything. OK, so I'm very nervous about the ground, and this is because I do some designing and have learnt just how painful it can be when you do not get it right, but also because I have seen and heard what a really well implemented ground can do. Ask Dan and Hugh what it can do either way.

And Scotty, "virtual" is just that, virtual, ethereal. I guess much like virtual sex. :mrgreen:

Cheers,
DVV