xlr vs rca

Fully balanced design, which is normally found on only some very high end equipment (such as Ayre, BAT, and Atmasphere, to name a few examples) provides a separate channel from input to output for both the "hot" (pin 2) signal, and the "cold" (pin 3) signal.

Don't know about the others but Atmasphere uses differential circuits, which even though balanced are not completely separate.

Modifying an SE cable by putting XLR connectors on it or using RCA to XLR adapters does not turn it into a balanced cable. It is still SE.

I think the salient points are:

1. if it is designed to operate as balanced use it that way
2. XLR connectors are better than RCAs but if you are using SE equipment you are stuck with RCAs unless you DIY.
3. In an electrically noisy studio with a myriad of equipment balanced has distinct advantages and that is why pro gear is balanced, but your house is not a studio.
4. With the large amount of excellent SE gear it is hard to argue that balanced is inherently better in a home environment even though those that make it and use it would disagree. You will hear the argument that I tried my balanced amp both ways and balanced sounded better so balanced is better. If it was designed from the ground up to be balanced it should sound better when operated that way, but it doesn't prove anything about balanced vs. SE.

Yes, very true. A lot of people post that don't have any idea what they are talking about.

The circuit Almarg described consists of 2 amplifiers or series of amplifiers one of which amplifies the inverted signal and the other the non-inverted. They can indeed be completely separate until applied to the speaker.

A differential circuit of the type used by Atmasphere consists of 2 tubes that share a common connection; the cathodes of the tubes. This is sometimes referred to as a long tail pair. It is difficult to explain circuit theory in a forum such as this but rest assured the 2 signals do interact in a differential amplifier. Applying a signal to either input will cause current to flow in both tubes. The circuit amplifies the difference between the signals, hence the name. It does not amplify any signal which is the same i.e. it rejects any common mode signals. If the 2 halves were separate and did not interact the circuit would not work as intended.

You can google it for more info.

Lewn,

Also, in any "balanced" design, an early stage, have to split the signal into positive and negative halves?

A phono cartridge can output a differential signal and most if not all modern DAC chips have differential outputs so no split is needed. It can start out that way.

I am just not aware of any other way to do it with tubes

you simply build 2 amplifiers in one chassis like stated earlier and one amplifies the + signal and one amplifies the minus. I don't know how all of the balanced manufacturers approach the problem but you can certainly do it that way. I did look through BAT's website and they make no mention of differential circuits. Perhaps they use them but don't talk about it?

Shadorne,

I'm afraid I don't follow. The balanced builders are just as likely to use gold plated connectors as the SE crowd. As for ground loops, take a look at my system. The phono is balanced into the pro box but it is converted to SE by transformers at the output of that box and is SE from then on. I run 107dB efficient horns with SET tube amps and even with the phono turned up I have to my ear up near the speakers to hear any kind of noise. No hum, no ground loops and I am biamping.

the ground loop is induced equally in both positive and negative signals

Balanced circuits are better at rejecting any noise from the power supply but your description of it doesn't make any sense. It isn't a ground loop problem.

If you care to be more specific about where he states this I would be happy to read it, but the link you gave has 10 papers on it and I don't care to read all of them trying to find it.

I understand the use of the CCS but I don't see where this makes the circuit immune to differences in the tubes. It's been awhile since I've studied them but as I recall any difference in the components will be reflected in the output.

Maybe I missed it but I don't see where it says anything about power supply leakage. What do you mean by that?

The insidious kind is when a power supply leakage affects ground on a device which adds modulated noise on your cabling as a function of power demands. The way to reduce this is to go balanced (so that the ground loop is induced equally in both positive and negative signals).

In order to affect a ground loop whatever is doing it has to change the potential of the ground. How does a power supply do that?

I think I'll bow out of this discussion. I'm told that there is no way the signals aren't separate when clearly they interact in the diff amps and then some vague references to leakage. It is really all pointless. Here's the bottom line. Those of you in the balanced camp can go on and on about all of the reasons why balanced "should" sound better than SE. You are correct; it should. There is a laundry list of reasons why CDs should sound better than vinyl. The simple truth is it does not. My ears and those of many others say that the best we've ever heard consists of SET amps coupled to high efficiency horns. I don't care what the textbooks say. I don't care how it measures. All I care about is how it sounds. Unfortunately there is no way to make that comparison via the internet.

{edit} I was writing this below as you posted so I had not read your last response. I agree, we are approaching this from 2 different angles {edit}

I know I said I was bowing out but I wanted to address your comment about convincing me. Of what? That balanced circuits have some inherent advantages in the area of noise performance or that because of these advantages balanced must sound better?

The former is a given, the latter is not. It is easy to fall into the same trap that Julian Hirsch did when he proclaimed the superiority of transistor amps that had extremely low measured distortion. They measured well but sounded like crap. The same trap that some fell into when CDs were declared to have perfect sound forever. It is easy to develop tunnel vision and focus on this one tiny area (noise performance) but the picture is so much bigger. If all else was equal would it be better to have the inherent advantages that balanced offers? Of course, but since it is not all equal the point is moot.

The proof is not what is in the textbooks but in what we hear. The type of system I listen to brings me pleasure that others I have heard do not. I've heard systems that have a low level hum that is easily heard at the listening position but when the music was turned up they sounded glorious. Sure, it would be better to get rid of the hum but if you sit there tapping your toe with a smile on your face how much does it really matter?

As long as you and yours are beating the "it measures better so it must sound better" drum and I and mine are only concerned about what really matters, which is how it actually does sound, then there is really nothing to discuss.