Whistling from a power supply

[rockhorst]

I just discovered that an old thread I started at the Madbean forum, after no initial replies, got some action going but no real resolution. Since this community is quite a bit larger, I want to post the problem here as well.

Here's the thing: some of my effects (most notably MOSFET booster designs like SHO and Orman's booster) generate an awfull whistling noise when used with a Godlyke PowerAll supply. With a OneSpot or Boss adapter there's no problem at all. It made me wonder what's so different about the Godlyke (don't own one myself, so can't open it up). Could it be clashing power filtering between the PowerAll and the pedal? Is there an easy way to remedy the situation, so that the pedals become 'PowerAll-friendly'?

For an example of the whistling sound, check out the video by Loztboy:

[R.G.]

Here's the thing: some of my effects (most notably MOSFET booster designs like SHO and Orman's booster) generate an awfull whistling noise when used with a Godlyke PowerAll supply. With a OneSpot or Boss adapter there's no problem at all. It made me wonder what's so different about the Godlyke 

Godlyke introduced their "Powerall" a few months after seeing the 1Spot being announced at NAMM.  Their booth was across the aisle, so they got a good look.

To the best of my knowledge, the Godlyke Powerall is different from both the Boss and 1Spot. I know the history of the 1Spot, not much about the insides of the Powerall. This is deliberate. Rumor has it that Godlyke procures the Powerall from an Asian vendor. That's neither good nor bad - nor proven, just rumor.

I do know that it took Visual Sound a long time to co-develop the 1Spot, testing it for whine, hum, gritz, gratz, etc. in pedal situations. It took some work. Stopping early and deciding it was good enough would have caused problems. I don't know how long Godlyke kept working on it.

Could it be clashing power filtering between the PowerAll and the pedal?

Somewhere between "probably not" and "no way". Power filters don't generally have any way to clash and whine.

Is there an easy way to remedy the situation, so that the pedals become 'PowerAll-friendly'?

The Devil makes me want to say that there is one really easy way - a 1Spot costs about US$25 retail. 

Just joking. I think what's going on is that both those pedals have very, very high input impedance, and it is possible that this common factor indicates some kind of pick up of whine. Generally, high frequency switching power supplies have switching frequencies much higher than audio, so they cannot be heard directly, and have to have some kind of RF interaction with an oscillator in the pedal to cause heterodynes down into the audio range. The pedals you mention don't have internal oscillators - at least not intentionally.

Does physical location near/far from the Powerall make a difference?

[rockhorst]

Yes, R.G. Joins in Right away .

Personally I use a PP2+ for my big board and a 1Spot for my smaller board. Both work great for the uses I come up with, So I'm already (quite happily) on the 1SPot bandwagon. The problem came up when I gave a pedal to a friend at a guitar store because he gave me a sweet deal on a guitar. He pulled out a Powerall to test it and we got a beautifull whistling to listen to. Disappointing when that happens to a gift. A good case against a Powerall (I can see you reservations on such statements RG).

We tried a few things, like cables, amps, different wall sockets. No difference whatsoever. Physical distance/moving it about didn't change it either.

What strikes me as weird is that I can't find any reports on this outside of a small DIY community. The Godlyke seems to be working fine for most people (as far as I can tell, mainly judged by the fact that my local guitarstore sells plenty, without much of a bias towards a 1Spot or a Powerall. They seem to be pretty much indifferent). I don't own one, but maybe later this week I'll try to borrow one to do some more experimentation. But there has to be something that makes a PowerAll work fine with a run of the mill Boss pedal vs. a much simpler (at least smaller, component wise) DIY pedal. It's a bit of guesswork at this point obviously.

Also, I know virtually nothing about switching powersupplies  

[Perrow]

I've got a T-Rex brand PS that I can't use for anything due to whining.