Our conversation with Dietmar Bräuer from Trinity continues with the latest essay; Balanced or unbalanced, that is the question!? “From my engineering perspective, this is a question that has only one answer – BALANCED. From a profit-oriented perspective, this is a question to which there is only one answer – UNBALANCED because implementing an unbalanced signal chain costs significantly less than building a balanced one.”
In audio, we have 3 main sources tape head, phono pick-up, and microphone, which do not request a connection to the ground and that makes these parts ideal for a balanced circuit design.
The TRINITY Phono and the TRINITY MIC preamp are fully symmetrical designs with very high gain, very high bandwidth, and no distortion at all.
The signal path is fully symmetrical from the input to the output and only the bias resistors of the input stage are connected to the ground.
The advocates of unbalanced signal processing refer to the fact that unbalanced signal processing sounds better, which is a purely subjective statement of the manufacturer related to his own devices.
This argument clarifies where the real problem lies, it refers to devices that produce a strong inherent sound and these are devices that add high harmonic distortions to the music.
The ideal audio device in the playback chain should never ever creates its own sound.
This statement “sounds better” may well be true for devices that exhibit high harmonic distortion, since balanced signal processing, if perfectly designed, cancels out the even-numbered distortions and thus the output signal contains only the odd-numbered distortions.
Odd-numbered distortions are perceived by the ear as harsh, whereas even-numbered distortions are perceived as warm.
The developers of pure single-ended solutions conclude that in audio amplifiers that produce high distortion, it is better not to remove the even-numbered distortion, because they superimpose the odd-numbered distortion, creating a different inherent sound that these developers call a better sound. In other words, you make a bad sound better.
The best solution, however, is undoubtedly to develop an amplifier that has no inherent sound, that is, amplifiers with distortion that can no longer be detected by the human ear.
In short, it may not make sense to design a balanced signal path if the electronics have inherently high distortion, as there is no benefit to a much more expensive balanced signal path.
To apply this “sounds better” statement, which refers to products with a high inherent sound, to all products is absolutely wrong and ignorant towards the manufacturers who have successfully implemented the advantages of a balanced circuit design in their products.
The politically correct answer of the advocates of unbalanced signal processing should be: Our subjective point of view is, that our devices sound better in single-ended mode.
Side Note: Just because a device only has RCA connectors does not mean that the signal processing inside also has balanced signal paths. A good example are DACs in which the output signal of the actual DAC circuit is balanced, which is then output to an RCA connector by a balanced – unbalanced circuit. Since these IC have only one supply voltage, the music signal is superimposed by a common-mode voltage which is removed by the balanced – unbalanced circuit for a DC coupled out signal.
The most important advantage of symmetric solutions is often cited as higher common-mode rejection, as these solutions were primarily used for line drivers and receivers.
But there are many more and, in my view, more important advantages, but you can only see them if you are aware of what the advantages of a negative feedback design are.
In the 90s I developed the complete electronics for a high-res digital video recorder (the only one at that time in Europe). To be correct I designed all the electronics between the error correction.
For the recording I used switched balanced current sources, since the balanced arrangement doubled the voltage compliance of the current sources which was essential since the data stream was in the MHz range and the fastest current sources were only feasible in a 5V technology.
For the playback, I also used a balanced approach to be exact a balanced amplifier as a “chip on board” with 0.56nV/√Hz directly behind the magnetic head. This solution has outperformed all before used single-ended solutions and I was convinced that the balanced signal path will always outperform the single-ended design.
TRINITY has made it it is business to develop audio electronics that have the best measurement results in the world and with this goal one can’t help but rely on fully symmetrical concepts and optimize them to the physical limit.
Every TRINITY device comes with a measurement report that proves beyond doubt that the approach chosen here for balanced signal processing is the only true one.