When discussing circuitry, there is a definite difference in a single-ended circuit and a balanced circuit in both the electrical interface, as well as in the sound produced by the system.
Single-ended interfaces use a “common” conductor (shield, ground or instrument chassis) as a signal return path. Balanced lines, on the other hand, use two dedicated conductors to provide forward and return paths for signal.
Fully balanced systems can have better sound quality due to the use of XLR connectors instead of RCA, immunity to extraneous noise, reduced demand on the power supply, and the inherent symmetry of balance.
But just because some preamps offer balanced inputs or outputs doesn’t mean the inside circuitry is balanced. Most unbalanced preamplifiers have a balanced input for compatibility with balanced-output components, but if the preamp’s internal architecture is unbalanced, you may still want to use the unbalanced connections.
User, Frepec, noticed that his preamp had both balanced and single ended jacks, which prompted the questions that follow, “I own a preamp which has both balanced and single ended jacks. I assumed that since I was using the balanced jacks I was getting the benefit of a balanced circuit. I have just now realized that just having balanced plug-ins doesn’t mean your preamp (or any other component) is “balanced.” Just wondering what sonic compromises are being made with equipment which has balanced inputs and outputs but changes the signal to single ended as it passes through it. If you are using the balanced outputs, what good is that if the signal going into this jack is single ended? I don’t understand what good is it to offer equipment with balanced capability only to revert to single ended signals. Is this just a gimmick to sell equipment or is there some advantage to not making the circuitry ‘fully balanced?'”
Almarg: Regardless of whether or not the component has a balanced internal signal path (i.e., is “fully balanced”), a well designed balanced interface will reduce susceptibility to ground loop effects; will to some degree reject noise/RFI/EMI that may be picked up in the cable; and may also reduce sensitivity to cable effects and cable differences. Having a fully balanced internal signal path provides additional benefits that are essentially unrelated, including reduction of certain forms of distortion.
However, the potential advantages of using a balanced interface between components having unbalanced internal signal paths will in some cases be outweighed by adverse sonic effects of the circuitry required to convert the unbalanced internal signals to the balanced signals that are provided to output connectors, and to convert the balanced signals at input connectors to unbalanced form. Also, I suppose that at least a few highly compromised designs may exist that don’t bother to include any conversion circuitry, and instead provide unbalanced signals to XLR connectors, which would negate the potential advantages of a balanced interface.
So if the components provide both choices, and are not fully balanced, the only way to determine which interface will perform best in your particular setup is probably to try both of them.
Atmasphere: If the gear uses transformers for input or output, then it can operate fine in the balanced domain with no tradeoffs. But preamps with input or output transformers are rather unusual.
Balanced operation was originally conceived to eliminate problems with interconnect cables and it does that very well, in fact so well that it does not matter if the equipment is balanced or not if it can drive the cable correctly- the difference is that profound. Its how the record industry was able to hang mics in a concert hall 50 years ago and at the other end of 200 feet it still sounds like music 🙂 But a lot of companies just install the XLR cable to be trendy. If that is what you have it will probably work no better than the RCA connection.
Well I’m a manufacturer so you have to take my comments with a grain of salt on this one: once you’ve heard a fully balanced setup there is no going back to single-ended. I’ve said that a lot over the last 20 years and it continues to be true.
jcmcgrogan2: Well I’m not a manufacturer, but you can still take my comments with a grain of salt. I have heard AND owned fully balanced setups. I am now back using single-ended, so obviously, there IS going back. The main reason for going back to single-ended designs was economic reasons. That being said, my current system is still very quiet and revealing. I will admit that the noise floor using a fully balanced system was lower, but once you factor in all the other noises in a real world listening environment, I can’t say that I’m suffering.
My current system is about 20% of the cost of my old big rig days, and to be honest, I’m embarrassed by how close it is sonically. To think….all those years of what I was sure were “upgrades”… Sure makes me wonder what I spent so much time and money obsessing over. Tube/SS, Vinyl/Digital, Balanced/SE, just relax, have fun and enjoy the music.
Charles1dad: I’ve heard exceptional sound from both fully balanced and single end RCA systems. Can’t say one bettered the other.
Do you have a preference for balanced or single ended setups? Do you think there is an important distinction? What have you found works best? Share your comments below!