PBM8 500 MKII Power Supply

The PBM8 500 MKII has a very robust power supply design consisting of a toroidal transformer usually found in high-end amplifiers. An advantage of these transformers is that they produce 1/10 of the magnetic field that conventional transformers produce. This is a useful property in high-end audio where signal noise is an issue.

Toroidal Transformer

One disadvantage of such transformers is that they tend to produce a higher inrush of current when powered. Hence, if you had an amplifier with one transistor open, the inrush would pass through only one transistor, which could damage it. Many high-end amplifiers use a "warming up" circuit that provides the power slowly when switched on.

PCB and Fuses

Each channel has two fuses, for the split-rail power supply. On this particular model the fuses were rated at 5 A.

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