For decades, the audiophile orthodoxy said linear (passive) power supplies sound better and switch-mode supplies were for laptops and cell phones.
But times and technologies change for the better.
A traditional linear power supply takes incoming AC, transforms it down with a big iron-core transformer, rectifies it to DC, and smooths it with banks of large filter capacitors. It works at line frequency — 50 or 60 Hz — and its noise behavior at audio frequencies is generally excellent. The downsides are weight, size, heat, and the fact that the regulation isn't very good, so output voltage moves around with load demand.
An active supply, like the new Hypex brutes we are using on the PMG Signature amplifiers, converts AC to DC at a much higher frequency — hundreds of kilohertz — and use much smaller transformers and capacitors as a result. An active supply can deliver enormous current, regulate its output tightly under varying load, and run dramatically more efficiently than any linear design. The catch has always been switching noise, something the wizards at Hypex have virtually eliminated.
A power supply doesn't care what the marketing brochure calls it. It only cares whether the design is honest about the work it's actually being asked to do — and our ears, in the end, are the only judge that gets the final say.
0 comments