Sean.......I appreciate the great minds that have created state of the art audio gear, be it fully balanced circuit topology or open ended. There is a great selection of gear in both camps. It is important to understand balanced interconnects are not the same subject as balanced circuit topology in amplifiers, preamplifiers, and source components.
All wire, no matter the length, acts as an antenna. Whether it is one meter, ten meters or more, wire absorbs electrical energy from the atmosphere. There is more electrical energy in the atmosphere today than ever before. We live in an electrical energy soup. Radio frequency interference (RFI) and electrical magnetic interference (EMI) are real and detrimental issues. Not only will RFI and EMI impact the purity of background silence in an audio component, the same electrical interferences will impact how circuits operates. RFI and EMI generate constant fluctuating voltages across a wide range of frequencies. This never ending bombardment of interference on interconnects is transmitted backward and forward into our gear. Again, the length of the cable is irrelevant since all wire lengths act as antennas. A perfect example of this is the simple T shaped dipole antenna used by many FM radio listeners on their tuners. It is just a length of wire, but most certainly absorbs and transmits electrical energy to a tuner's antenna input. Fortunately for a tuner, it wants this electrical energy, but other equipment has no use for it.
A primary advantage of a balanced audio interconnect is its ability to cancel RFI and EMI energy induced on the wire through phase inversion on the hot and cold signal wires. When the out of phase signals are recombined RFI and EMI energy is totally canceled. In addition, the shielding on a balanced interconnect helps to further reduce RFI and EMI energy from reaching the signal wires by absorbing the electrical energy in its woven shield and shunting this energy to ground. This is why balanced interconnects are nearly 100% immune to having 50/60 cycle AC hum induced into the audio signal path. The pros know this and that is why balanced cables are the primary choice for critical audio applications.
My personal experience with unbalanced audio interconnects has been hit and miss. I use unbalanced interconnects on certain gear and always have to pay particular attention to where the interconnects are routed, always attempting to avoid being parallel to any AC power cords. This can be very difficult to achieve. I have had 60 cycle hum issues many times from not properly dressing unbalanced interconnects away from AC power cords. I have had zero issues using balanced interconnects in parallel runs with AC power cords. Any induction from an AC power cord into the audio signal's wire gets canceled when the out of phase hot and cold signals are combined. It is this advantage that drives my desire to use balanced audio interconnects whenever possible, even on short runs. The combination of high quality shielding and balanced interconnect signal wires help keep the overall signal to noise ratio of my audio systems at a maximum. I also believe the circuits in source components, preamplifiers, and power amplifiers are able to more faithfully reproduce audio signals when they are less likely to have to deal with the adverse electrical forces of RFI and EMI being injected into their circuits.
My final point is about the connectors. An RCA connector makes an inferior connection when compared to a XLR connection. If you plug and unplug RCA connectors very often, and what audio enthusiast doesn't, the connectors become worn and loose, the connector and RCA plug gold plating becomes scored and worn. Balanced XLR connectors are designed to allow continuous use and the best ones offer locking capabilities to ensure no accidental disconnects while the equipment is energized.
Ultimately it is the end user who makes the decision about what type of interconnects to use. I don't condemn the use of unbalance interconnects or equipment designed to use unbalanced interconnects. There are electrical engineers designing fabulous gear that embraces both concepts. I use unbalanced interconnects when I don't have an option, but my preference is to take advantage of the noise cancelling properties of balanced interconnects and superior connections whenever possible.
