Noisy power supply—am I doing it wrong

[BobbyT]

Hi all,

I recently started using multiple effects after many years of only using one pedal at a time with whatever power supplies they came with.

I am looking to assemble a mini pedalboard, and I have a question about power supplies.

I am getting a crap ton of noise with my 1spot. Do I need some kind of fancy isolated brick thing, or am I just doing it wrong?

I am currently using a Boss OC-2, an EHX Bass Big Muff, and I am looking to add a compressor in the near future. I am attempting to power them with a 1spot daisy chain.

This setup works fine in my house, but when I use it anywhere else there is a massive amount of noise, to the point where it is unusable. When this happens I just unplug the power to both pedals and run off batteries and the noise goes away.

Any advice would be most welcome. Many thanks in advance.

 

[Joeywhat]

Does all the wiring inside the problem unit look OK? Everything is properly grounded and connected/soldered?

 

[Killing Floor]

Is it an isolated supply?

 

[BobbyT]

Does all the wiring inside the problem unit look OK? Everything is properly grounded and connected/soldered?

Everything inside both pedals looks fine and they both buzz like crazy with the 1spot. No buzz with battery power. I have not opened up the 1spot…

 

[BobbyT]

Is it an isolated supply?

I don’t think so. It’s the regular $20 1spot:

 

[Lostgallifreyan]

I don’t think so. It’s the regular $20 1spot:

View attachment 4873052

That thing costs 20 dollars?! I never saw a PSU that size and shape that I'd accept, even as a gift. They were all aimed at being as cheap as possible.

If you can, find one with a ground wire in the mains side, and a coaxial cable for the low volt side. That way you at least know that the maker tried to design for low noise and good safety. Coax cables tend to be more flexible, or at least equally so in all directions, so less likely to stress your pedals' power input sockets.

 

[BobbyT]

That thing costs 20 dollars?! I never saw a PSU that size and shape that I'd accept, even as a gift. They were all aimed at being as cheap as possible.

If you can, find one with a ground wire in the mains side, and a coaxial cable for the low volt side. That way you at least know that the maker tried to design for low noise and good safety. Coax cables tend to be more flexible, or at least equally so in all directions, so less likely to stress your pedals' power input sockets.

Any recommendations for a moderately priced power supply that meets those criteria?

I guess I’m also a bit confused because I understand that many people use the 1spot with no issues, so I thought maybe it was user error.

On a side note—as a fellow Whovian I love your handle.

 

[Killing Floor]

A One Spot or other “wall wart” is fine for a single pedal. For multiple devices sometimes you have issues and sometimes you do not, as you have seen. I use Cioks but there really isn’t a best brand. Those isolation transformer power blocks are the way to go. One Spot makes them as well.

 

[Lostgallifreyan]

Thankyou. Would I be playing Devil's advocate if I mentioned that it does not specify exactly which Gallifreyan was lost?

Doesn't sound like user error to me, or at least not an obvious one, because you got good sound except in other contexts than your own. Examining all your circuit grounds is a good idea on general principle though, you might find something to fix, and by so doing, improve your odds.

I didn't have any specific recommendation, I'll admit the one thought that dominated was that of the small Dell PSU's I'd collected over some time, from old PDA's, but they're 5V and have no mains-side grounding.

What occurs to me now is what Killing Floor said about isolated power supplies, because if you're using more than one pedal it's worth getting into this, because supplies aimed at powering multiple pedals with isolated supplies effectively emulate batteries. The expense now will easily be offset by the pain they spare you in the long run. They may also make it easier to try pedals with unexpectedly high loads or unusual voltages.

I'll leave it to people who have something like this to make recommendations. (I use a single multi-effect unit as a way round the problems of many pedals).

 

[HelpImaRock]

Any recommendations for a moderately priced power supply that meets those criteria?

I guess I’m also a bit confused because I understand that many people use the 1spot with no issues, so I thought maybe it was user error.

The One Spot is great because it supplies more power than the typical wall wart that comes with a pedal. You can daisy chain more pedals cheaply and have a bigger board. However, there's no isolation. You may have a pedal that doesn't like being daisy chained and makes the signal noisy whether it's on or off. You may have bad wiring in your home or at a venue. And that all gets exposed with an un-isolated signal chain.

I use the TrueTone CS6 to power my main board. It's basically a One Spot with a bunch of isolated outputs. Most pedalboard power supplies follow that kinda topology. Just stay away from the cheap ones that say they're isolated but aren't.

 

[skyline_01]

A One Spot or other “wall wart” is fine for a single pedal. For multiple devices sometimes you have issues and sometimes you do not, as you have seen. I use Cioks but there really isn’t a best brand. Those isolation transformer power blocks are the way to go. One Spot makes them as well.

+1 for an isolated block. I think if OP is building up a pedalboard (even a mini one) then the extra $ would be well justified. One less thing to worry about at a gig or in studio.

I recently went from a no-name, non-isolated supply to the Eventide Powermax (made my Cioks). I'm powering seven 9v pedals (including a 500 mA tube DI) and a 15v Radial Bassbone OD and it's not even breaking a sweat. Zero noise too - and I shaved off 1.5 lbs by ditching wall warts and adapters.

 

[Killing Floor]

The One Spot is great because it supplies more power than the typical wall wart that comes with a pedal. You can daisy chain more pedals cheaply and have a bigger board. However, there's no isolation. You may have a pedal that doesn't like being daisy chained and makes the signal noisy whether it's on or off. You may have bad wiring in your home or at a venue. And that all gets exposed with an un-isolated signal chain.

I use the TrueTone CS6 to power my main board. It's basically a One Spot with a bunch of isolated outputs. Most pedalboard power supplies follow that kinda topology. Just stay away from the cheap ones that say they're isolated but aren't.

Yep. If you are daisy chaining that is likely contributing. Next time you have this noise issue remove 1 pedal at a time. Not all circuits have the same grounding, shielding, etc. when you daisy chain that DC you are effectively sharing the issue. Not all buildings are grounded equally. There are many potential causes. Isolating the power to each device is an advantage against many common electric issues that worsen noise.

 

[micguy]

There are valid reasons why more expensive, isolated power supplies exist. You now know why. The solution here is obvious, but yes, it will cost you some money.

 

[Lenny JG]

Get an isolated power supply, don't cut corners w/ your tone

 

[Justin Keoni]

In my particular situation, I purchased a Cioks DC7, a Strymon Zuma, and even a Truetone CS6 and they all added noise to my signal. I don’t know if it’s the 40 foot LED wall behind me or the massive amount of moving lights, but the switchable power supplies don’t work well on our stage. For some reason the $20 1Spot and the Walrus Aetos were the only 2 supplies that worked silently. I know these high end power supplies are great and much loved, but every scenario is different. I get zero noise running 7 pedals off of 1 daisy chain, and these pedals are even a mixture of analog and digital. Just be sure the power consumption is less than the 1700 it’s rated for.

 

[JimmyM]

If you use one pedal at a time with no hum, you would be a candidate for isolation. I got away with a 1 Spot for years powering a bunch of pedals until I got a couple that didn’t like sharing a line. It was either that or have 4 1 Spots, and I knew that would drive me bonkers more than buying an iso PS.

 

[Jev1]

Like Jimmy, I also used a 1-Spot for years for multiple pedals daisy-chained on my board... until I found that one pedal that didn't play well with the others on a chain and caused a crap-ton of noise. I went to the MXR Iso-Brick power supply, and it's been good. (Plus.... added bonus, the LEDs on the Iso-Brick light up my board a bit so I can more easily see my settings on a dark stage).