How does PowerPlant MW eliminate power amp power-up buzz?

What could be better than one PowerPlant? Obviously, two. I have just received my second PowerPlant P3 for my office system. I have a question on how its MW magic works.

It is generally known (but not formally acknowledged) that Bryston power amps have a “power-up buzz” that seems to vary somewhat in intensity between individual amps. I don’t know if similar A/B designs have this characteristic. Owners are assured this is normal and nothing to worry about and does no damage. But, it is damn irritating! A “fix” would add components that would degrade the audio path (this is not Bryston’s official position). I have run into several explanations that suggest this is the result of the capacitors and transformers “charging up.” Indeed, if you power down, then back up fairly soon, there is no buzz.

Now, here’s the amazing thing: if the PowerPlant is set to MW (Multiwave) mode, the buzz goes away. Turn MW off and you the buzz returns. Turn it on, it’s gone. You get the idea… Now, I’m not interested in thoughts on perceived deficiencies of Bryston’s design, as I very much like their resulting sound. But, I’d LOVE to know what is going on!

If this happened regardless of MW mode, I would assume it is something like high impedance in my house wiring. Since it works only with MW on, that theory is shot!


Just a guess but MW results in a wider peak in the voltage waveform which is where the capacitors are charged so they should be charging up more quickly.

I do support Steve’s guess :slight_smile: