We’ve been focusing on amps and their design philosophies as a precursor to the release of our new power amplifier this summer. I thought it instructive to write about the various types of amps, their good and bad points and the power requirements for loudspeakers of all kinds.
The one thing we did not touch upon was Class D power amplifiers, the most efficient of them all, and the basis of the output stage of our new PerfectWave Power Amp.
Much has been written about this type of amplifier – mistakenly referred to as a digital power amplifier – and I thought it might be good to delve into the workings of this analog amp.
I also wanted to mention that one of the biggest drawbacks of this amp type, at least in the past, has been the same sort of drawback tube power amplifiers have: a big magnetic block of wire between the amp output and the speaker.
In a tube amplifier this mass of wire and iron is an output transformer and, in a Class D amp, it’s an output filter and integrator. Both are quite necessary for the operation of the amplifier and both have represented an Achilles heel when it comes to performance – but in recent designs of Class D amps this drawback has been all but eliminated – and performance limitations are no longer an issue because of this output device.
Tomorrow we start to understand how the amp works and as we progress down this path we’ll discover some of the advancements in designs that make this growing technology ever more musical than you might imagine.
Paul McGowan – PS Audio, Intl