balanced connection, better than single ended?

10-03-10. Phd: The Audio Research amp that I purchased is a true balanced design. But more importantly I like the way it sounds. I used to own it two years ago and never took advantage of its balanced technology but was thinking that this time I should try it in its fully balanced mode because maybe I missed something but now I'm not sure.

I could be wrong, not being familiar with the specific design, but I suspect that you were getting much of the benefit of the amp's fully balanced internal design without realizing it (contrary to some of what has been said above).

Since the amp is fully balanced internally, and provides rca as well as xlr inputs, I would expect that when the rca inputs are used there is circuitry at the front end of the amp that performs a single-ended to balanced conversion. That would allow the benefits of fully balanced INTERNAL design to be retained, at the expense of the possible sonic side-effects of the extra circuitry (which I would expect to be minimal or negligible in an ARC or other good design).

Some of those benefits, which have not yet been mentioned in this thread, are cancellation of some forms of internally generated distortion, and loading of the power supply that is more constant than with most unbalanced internal topologies (other than Class A). That in turn reduces internally generated noise, and possibly also inter-channel crosstalk in the case of a stereo amp.

Those benefits would NOT be realized, btw, in the case of a fully balanced amp that does not provide rca inputs, if a simple rca-to-xlr adapter were used at the inputs, which is an approach that would make no sense with a fully balanced amp. They WOULD be realized if something like a Jensen transformer were used to convert single-ended to balanced.

As far as the benefits of balanced EXTERNAL connection are concerned, I would add greatly reduced susceptibility to ground loop issues to what has been mentioned. That will sometimes be significant even with short cable lengths. That benefit, and also the common mode noise rejection that has been mentioned, will be realized regardless of whether the components are balanced internally or not. Although if they are not balanced internally, the possible sonic effects of the extra stage required to perform single-ended to balanced conversion may present a tradeoff.

All of those factors, of course, can be outweighed by many other variables in any given system, so I agree with the several people who have suggested experimentation and going with what sounds best. For initial experimental purposes, at least, you might want to consider purchasing a pair of inexpensive pro-oriented Mogami xlr cables.

Best regards,
-- Al

"The Audio Research amp that I purchased is a true balanced design.... I... never took advantage of its balanced technology"

I am not sure I understand meaning of the word "true balanced design"....as oppose to "false.."?

I guess that your ARC amp has FULLY balanced design. I define word "fully" as balanced from the beginning to the end of the signal path.

If so then you did big mistake ny not utilizing fully balanced design since you already paid for it and had it!

Lets clarify the terms confused by some audiophiles

1 - XLR termination - does not mean anytning. It could lead to "true" balanced input stage or its negative signal is immidiately grounded thus converting it into single ended input signal.

2 True balanced input. Can utilize the number of connections. E. G. one XLR or as its done on Spectron amps (as an option to use) two RCA inputs (one positive and another is negative) - I use it in my own system.

Its advantage is described above - reduction of noise upstream. Nothing more ! I have tube preamp (Joule-Electra LA-300ME) with RCA outputs and when I place my ear to the woofer of my speaker I hear nothing, no noise, nothing...so for me and many, many, many others balanced input provide nothing. (again if you have 100' cable and its raining and stars allign badly etc then you better off with balanced input)

3 Balanced amplification. There are a few implimentation of it. As one of them let look at Joule-Electra LA-300ME preamp. It has RCA input, then the phase splitter splits the input signal into two (positive and negative) and TWO SETS of amplification stage or stages amplify them . Next the one signal is subctracted from another (positive - negative = positive x2 - double signal or in this case double half-signal). However, please note that as oppose to the noise - distortion produced by this amplification stage or stages is not random event and therefore, in "ideal amplifier" both positive and negative distortions have identical amplitude but oppose phases and distortions are therefore CANCEL each other during subtraction stage. As a result you have distrortion free music.

Distortion-free music is spectacular !!!!!!!!

Finally, "300" outputs this already distortion free signal via RCA (single ended output).... and you do with it whatever you want

4 Fully Balanced Design where you have balanced inputs, outputs and most important (and most $$$$$$$$$$$$$) balanced amplification.

IMO, to have fully balanced amplifier and use only half of it is crazy..... You got to speak with manufacturer of your equipment to untilize it in FULL.

I must state for the record that some (e.g.differential) balanced amplifiers will still utilize your single ended signal but most probably not in fullest extend - it can be debated.

Example: Joule-Electra fully balanced preamp LA-450ME. As amplification it balanced twice i.e. has twice more stages as LA-300ME. One set remove distortions as explained above - but in real world amplifier you can't cancel them to zero, part toletance is not 100% thus another set cancel residuals and if you look J-E web site you will see that distortion level drops 8 times going from "300" to "450".

Double Distortioin Free amplifier is double spectacular !!!!

At any rate, Joule-Electra can add single ended input (RCA) and phase splitter so you will use all 450's amplification stages even if your input signal is single ended.

Hope it helps - if not my apologies

Phd,

"maybe I missed something but now I'm not sure. But I still want to see for myself".

That's the ticket. My ears are directly coupled to my pocketbook and by that I mean not going cheap, just getting some improvement for the money I spent and being aware of law of diminishing returns. That doesn't always happen when you buy theories or marketing.

I wonder what happens to a balanced preamp when the parts drift out of spec as they age. Single ended would age also but it's not relying on an identical twin aging at the same spec. I've never been able to get all 4 of the tires on my car to age at the same rate even with the rotate/balance ritual.

The raison d'etre of balanced line is to be able to use any balanced cable cable of any length (or cost) and have that cable have zero sonic artifact. So it does not matter the length (nor price); there is always an advantage to balanced lines.

In order to achieve that, the balanced line standard requires a low output impedance of its sources. This is poorly understood by the (IMO) majority of high end audio manufacturers, who often seem to regard balanced lines as trendy rather than the serious sonic boon that it is. As a result many high end audio products do not handle balanced signals nearly as well as they should, leading to varible results. This is why you see this question come up time and again on these forums!

A common myth is that balanced circuits require twice as much circuitry. This is untrue- quite often they require **less** circuitry as you have less noise, and thus less need for as many gain stages. Also, to build a differential balanced circuit does not require double the parts of its single-ended counterpart!

Yet another myth is that there is no advantage to using a balanced circuit with a single-ended input. As pointed out by Al, you retain the advantages of the circuit, you only loose the advantage of the cable. The gain **does not** change- that is to say you do not loose 6 db, as, at least with differential circuits, the input is looking for the *difference* between the inputs, which might be 2 opposite phases, or it might be the non-inverting input and ground. The differential input does not care.

Hello Arthmaspere.

" The raison d'etre of balanced line is to be able to use any balanced cable cable of any length (or cost) and have that cable have zero sonic artifact. So it does not matter the length (nor price); there is always an advantage to balanced lines."

By saying that "...that [balanced] cable have zero sonic artifact" do you imply that any sonic effect of cable capacitance, inductance and other electrical characteristics effecting the single ended cable sound - vanish? Gone? Diminished?

I would much appreciate if you can expand on this very interesting statement

Next point: Spectron wrote:

"I must state for the record that some (e.g. differential) balanced amplifiers will still utilize your single ended signal but most probably not in fullest extend - it can be debated."

and indeed you debate it - which is absolutely fine and even great! However, it confirms Spectron strong recommendation:

".... You got to speak with manufacturer of your equipment to untilize it in FULL."

Indeed, there are so many ideas, designs, technologies, ways of implementation that its almost a must.

Thank you !