How quiet should a PSU be?

[Coma]

Picked up a Mooer Macro Power S12 a few weeks back to replace my Palmer PWT 05. I noticed a distinct hum coming from it, even without pedals plugged in, so the dealer replaced it for me. The new one still hums, though not as bad.

Today I borrowed my bass player's T.Rex Chameleon and I ran the three of them side-by-side, at first in our rehearsal space and then at home.

I'm getting hum from all three, the worst culprit being the T.Rex. The Mooer has air vents on three sides, and the noise emanating from it is audibly different in pitch depending on if you're listening to its covered or ventilated sides. The Palmer's- the cheapest by far of the three - noise level is almost unnoticeable unless you press your ear to to. All three units have isolated outputs.

Now, I suspect part of it is due to the very old wiring in my somewhat old apartment building. But it made me wonder, when people say a power supply is quiet, do they mean "dead quiet at all times" or "doesn't cause excessive noise when pedals are plugged in"? Furthermore, I thought about sending the Mooer back and replacing it with a TrueTone CS12, but now I'm not so sure that would actually help.

[PFDarkside]

Re: How quiet should a PSU be?

It’s referring to inducing hum in the pedals. The Chameleon has a little noise if you listen for it, but it’s very faint right? I don’t recall the Voodoo Lab ones making any noise but either way, just moving drowns it out, let alone playing. I use the Chameleon because of how versatile it is (high current capable, AC capable, 12V and 18V capable, nearly every pedal I have can be powered by it so changing stuff out is a piece of cake)

Although they don’t provide AC, I bet the Truetone and Strymon supplies (what others use the latest generation of switching power supplies?) are silent. The irony is that those used to be the noisiest when they switched in the audio spectrum and weren’t well filtered.

[Coma]

Re: How quiet should a PSU be?

The Chameleon is noticeably hummy to my ears, so much that I find it a bit annoying. But all of that is transformer hum. Same in the rest of 'em.

[DavidRavenMoon]

How quiet should a PSU be?

Transformers hum.

If you have a digital switching power supply it won’t hum.

Is that hum coming through to the amp? If not don’t worry about it.


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[Coma]

Re: How quiet should a PSU be?

No, hum isn't procrrating, so to speak. I just tried the rig at home and I have oddly good hearing so it bothered me. But no, it's not noticeable over any amp.

[VinceT]

Re: How quiet should a PSU be?

The transformer hum in my TRex Chameleon is very loud, and worse it induces noise in any drive pedal that is too close physically to it (some drives more than others).

It is so bad that I relegated the Chameleon to my smaller board, and went with a Truetone CS12 for my main board - that is very, very quiet - slight transformer hum, but very slight - and it doesn’t cause any interference with any of the pedals on the board. I’m very happy with the CS12.


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