Sine or Multiwave function


Does this statement mean that there is audible hum coming from your amp when plugged into the wall socket? Maybe try a different circuit. That amp should be dead silent.


@RonP There is, but when you stick your ear right next to it, I talked to Kent English about it and he said there is going to be a slight hum from it as the transformer is huge. I just ordered a emotiva cmx-2 to check to see if filtering out dc makes any difference.

I’ll test from the wall and the P20 both and into the p20 as well


Also I did try all three dedicated circuits and some of the non dedicated with an extension cord. Same amount of low level noise


I wish my BHK S300’s were silent but one isn’t. The hum is audible from the listening position when no music is playing. PSAudio fixed one but couldn’t fix the other.
Not the best outcome.


I went over and put my (good) ear as close to my amp as I could without setting my hair on fire and there’s not a peep. Then I asked my gf to do the same and she told me I’m crazy and left the room.


Is that crazy for liking Porches or crazy for asking her to put her both good ears near the amp and listening for a hum… I’m just sayin… :woozy_face:


Can’t be the Porsche thing because I’m Corvette crazy too.


R, I was going for bending over and listening to a hot hum… my wife was watching me type so I waited till she went in the other room… I’m just sayin… :mask:


You both are awesome @ronp and @cadri.

I will see after I get the dc blocker and then call Pass again and see if they still tell me the same story if it’s not DC.

Thanks again!


DC blocker didn’t change anything. Called Reno Hi-Fi and mark says the faint hum I am hearing is normal. So really just an issue with the p20 in normal sine wave mode is actually making it worse (and the 5 other multiwave modes) only multiwave mode 6 doesn’t cause any noticeable difference.


Hi Veneet,

Our Chief of Engineering had a couple of comments about this:

It’s not unheard of. The low impedance of the power plants means that the charging spikes in the amplifier power supply are larger and you can get more mechanical noise from the transformer. I’m a little surprised with a Pass amp though. MW is a good solution for that. Sometimes lowering the voltage setting a couple volts will make a big difference on a marginal power supply transformer.

He is curious if the noise is the same for both P20’s you had used?

  • Jeremy


Hi Jeremy,

Thanks for checking and getting back to me. Unfortunately, I only had the other p20 setup for one day and didn’t have the time to get down to all the different noises that were happening.

I never investigated multiwave at the time, as you and I diagnosed that the powerbase was causing that very loud noise and having disconnected that solved at least that issue.

I just tried changing voltage on both sine and multiwave and no different sound from the buzz from the amp on sine and the first 5 multiwaves.

Multiwave 6 was also unchanged and had no additional buzz that the other setting did, so it was just like going to the wall.

I just this minute plugged in the powerbase to the new P20 and there is no noise from the powerbase or p20.

EDIT - my scopes are blank now however


My system sounds a lot better with multiwave…alot. Night and day.


Whatever happened with the blank scopes?


Is it me or does it seem really dynamic, more real, and the bass seem more impactful? It did to me. And I don’t mean like low subwoofer bass, but the kind from kick drums and stuff.


A reboot brought them back after I was told I could check on making sure if the oscillator card was in firmly. The card was in place but the weird issue with the scopes, coupled with some odd behaviour where I found it flipping back and forth from the screen where you hit auto tune and the meters one morning for no reason, and a high pitch sound coming off the P20 transformer that I heard distinctly when the lid was off made me take their offer to replace it. New one comes Monday. Jeremy and Mark from PSA have been great.


Yes, exactly. MultiWave is always on with my Power Plants. It really help impact and kick drums and adds a sense of power to the system. Technically MutliWave is the same thing as adding more capacitors to your connected gear’s power supply. You can actually
see the power supply ripple go down—which is what you’d see with bigger caps.


Strange, I hear no difference.


I use it too! Multiwave sweetens everything up.


I notice a difference between the two and prefer MultiWave. What MW setting do you guys use? I set mine to 3.