What is a good power supply

HiFi system: importance of the power supply

Reading time: about 3 minutes

Why the power supply for hi-fi systems plays such a big role

As we all know, every socket has a voltage of 230 volts. However, our hi-fi systems work with voltages between 6 and 60 volts.

Every hi-fi component therefore has at least one transformer that reduces the high mains voltage to the required working voltage (s). But: our devices require DC voltage, but AC voltage is present at the wall socket. This alternating voltage is brought to the desired voltage level by the transformers, but it still has to be converted into a direct voltage.

With the help of diodes, the voltage in analog power supplies is "reversed" at the right moment, so that the AC voltage ultimately becomes a DC voltage. However, the “direct voltage” generated after the conversion by the diodes is anything but “equal”, at least in the sense of being equally high and constant.

The freshly generated "DC voltage" fluctuates at twice the rate of the mains frequency. One hundred times a second, because the usual bridge rectifiers fold the negative half-waves upwards. If the audio electronics of our components were to be supplied with it "without further treatment", we could hear a distinct hum or whirring sound from the loudspeakers. This noise would then have a frequency of exactly 100 Hz.

Now the capacitors come into play. They have the function of a voltage store here.

If the mains voltage drops, the voltage on the capacitor is maintained. Our audio components can now cover their power requirements for a short time through the capacitor. If the mains voltage increases, the capacitor is "recharged" again. Of course, this can only be done at the voltage peaks, i.e. exactly 100 times a second. So only the very brief moment of the voltage high can be used to supply the capacitor with fresh electricity.

Since the external power supply is not constant, but rather pulsed, larger currents must be able to flow briefly via the fuse, power cord, plug and socket!

Therefore the quality of the supply line, the quality of the contacts of the socket and connector strip is extremely important. Anything that hinders the unhindered flow of electricity has an unfavorable effect on the sound.


The last meter to the hi-fi system is particularly important

The short distance from the wall socket to the hi-fi system is particularly important from many points of view. The reasons for this are:


  • Radiation of high frequency
    The short connecting cable from the wall socket and from the power strip emits high frequencies that were emitted by other devices (digital electricity meters, plug-in power supplies, dimmers, computers, household appliances, etc.) via the house distribution.
  • Good tuning options
    While only a qualified electrician may make changes to the house installation including the fuse box, you are in control of the “last power mile”. Or rather, master of the last few meters.
    It is up to you whether you use high-quality power cables and power strips in this area to improve the performance of your audio chain or not.



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