To get the most out of your balanced headphone system, it’s important to use superb audio gear that provides true differential 'balanced drive' signals. Our HeadRoom Ultra Desktop DAC is just such a device. The advantage of this balanced method -- first released by HeadRoom in 1999 -- goes far beyond simply reducing induced noise; amplifier slew rate is doubled, most THD harmonic distortion components are suppressed, and a doubling of voltage output power is realized resulting in a supremely accurate and smoothly open-toned sound not possible with standard headphone systems.
With typical 'unbalanced' audio connectivity, the audio signal is carried on a single conductor, while a shield or ground conductor is provided for the return current path. A differential balanced drive system uses two audio signals: a normal audio signal, and a perfectly matching but inverted [positive/negative] audio signal. A ground conductor may be used as a shield, but is technically not required in these topologies.
Balanced drive has long been used to reduce interference on long cable runs with microphones and pro audio componentry, for example. But while some gear may offer balanced XLR connections externally, they are often single-ended devices internally, which are either transformer-coupled or use complex phase splitters to create their so-called balanced signal. These methods invariably result in the normal and inverted audio signals acting as slightly imperfect, fluctuating mirror images of each other, and in reality only serves to degrade the full acoustic performance potential.
In a true fully differential balanced drive system, a source of perfectly matching balanced signals is followed by identical, highly-matched signal paths. In the HeadRoom Ultra Desktop DAC the signals are perfectly created by painstakingly paired sets of DACs that are running in normal and inverted positive/negative modes and therefore create, again, perfectly matched output signals.
Interestingly, a balanced LP turntable phono stage could be used by taking the signals of either side of the LP cartridge coil and running the signals through identical RIAA equalization curves and output driver channels!
