Most components carry their own power supply inside the box: a transformer and regulators that turn wall current into the clean DC the circuit needs. An external power supply moves that job into a separate chassis, often a bigger and better one than the original box could hold, and connects by a dedicated cable. Naim's NPX 300 and NAPS 555 DR, MOON's 820S, Rega's Neo PSU and Linn's Radikal all work this way: they replace or bypass the supply built into a specific component, and they only fit the components they were designed for.

The gain is twofold. The transformer and its magnetic field move away from the sensitive circuitry, and the supply itself is usually far more generous, so the component sees a steadier voltage under load. On a turntable, a dedicated supply also drives the motor with a purer waveform, which is why speed stability and background silence improve.

A linear power supply is a type, not a fit. Small components such as network switches, streamers, DACs, routers and phono stages often ship with a plug-top switch-mode adapter: light, cheap and electrically noisy, because it chops the mains at a high frequency and that hash rides into the signal. A linear supply does the same job the old-fashioned way, with a transformer, rectifier and quiet regulation, and no high-frequency switching.

Nordost's QSOURCE and Clearaudio's Professional Power and Smart Power are linear supplies. Rather than being matched to one product, they offer standard DC voltages on several outputs, so one box can replace the adapters for a switch, a streamer and a phono stage at once. If the component has a barrel-jack DC input, a linear supply almost certainly fits it.

In short: an external supply upgrades one component it was built for; a linear supply replaces the wall adapters of anything that uses them. Ask us which you need, and we will check voltage, polarity and current before anything is plugged in.