15. Power supplies

Even experienced audiophiles will at times state that acoustic treatments to the room provide the most significant foundation for a HiFi system. However, while this surely can be a significant corner stone, I find that one small thing is overlooked in this statement, and that is the effect of power on our system. If I was to identify the most significant contribution to a system’s sound, power would be first on my list. If you take away the room, you will still hear sound, but if you take away the system’s power -

In steps 1-5 of this forum, the significance of power on the sonic nature of our HiFi-system has been described at great length. It is not surprising, therefore, that internal and external power supplies will have a similar impact on a unit’s ability to perform. Although the amount of power needed at any given time is relatively small for most units, especially when listening at 70-80dB indoor volumes, a power supply’s ability to deliver ultra quick, resonance and interference free electricity in the end will make the difference between our system moving towards High End or remaining stuck in HiFi.

A few weeks into listening to the Cambridge DAC, I noticed that the music’s highs seemed a bit tin-like and unrounded, e.g. on acoustic guitars, while the bottom end was lacking in natural punch and fullness, e.g. on lower piano keys. Later, while running some tests on the quality of electricity in our house, we noticed some regular spikes and general noise floor emanating from the switching of the Cambridge DAC’s external power supply, basically an unforgivable oversight for such an important part of our system. Therefore, against the manufacturer’s advice and warning, it was high time to make a change.

The power supply shown below was brought in to replace the cheap plastic China-made trailing edge transformer that had been found to inject local distortion into the whole system. With the new power supply, the sonic signature of the DAC changed from edgy and light to smoother and more balanced. Low piano notes now have a more satisfying punch and noticeably slower decay, much like on a natural instrument.