Ground loop hum?

[Andyfreddy]

I have a pretty constant ground hum with all my guitars, in all the following situations,

-1-spot powering a NUX Stageman floor, with any acoustic guitar.
-1 spot powering a Boss GT-1, with any acoustic or electric guitar.

The thing that stops it is unplugging the boss GT1 and running it on batteries.

Is there a way to stop this?

Thanks!

[YamahaGuy]

What is your "amp?" Are you running your gear into a PA? An amp? If so, are your Onespot and that "amp" plugged into the same electrical outlet? If not, they should be. A DI box with a ground lift switch could help.

Are you using an instrument cable [not a speaker cable]?

[jonfields45]

A power supply with isolated outputs will work like the battery.

The NUX is putting noise on the 9v DC power connection that the tuner is unable to reject. Many older pedals have this problem when paired with a newer digital pedal on the same daisy chain. My UA Dream 65 specifically mentions it requires an isolated power supply and it was able to make a Tube Screamer and a Boss TU-3 hum badly when daisy chained with them.

Another option is a new tuner such as a TC Polytune Pedal which will be able to reject that noise and is true bypass when not engaged.

It is the emitter follower single transistor buffers common to old not true bypass pedals that is causing the problem, in addition to the noisy power consumption of the new DSP based pedal.

[tadol]

You can test by using a 2-3 prong adapter - my friends Hot Rod Deluxe had a pretty bad hum, but I gave him one of those and hum disappeared. He probably should have it checked out, but thats his call -

[ljguitar]

Originally Posted by tadol

You can test by using a 2-3 prong adapter - my friends Hot Rod Deluxe had a pretty bad hum, but I gave him one of those and hum disappeared. He probably should have it checked out, but thats his call -

Hi tadol…
It's rare I get hum, but I always have a 3-to-2 prong AC adapter in my gear bags. It's a life saver when you are plugged into the same circuit as the coffee pot in a street-front cafe (one time I hit this scenario and the adapter eliminated the hum).

[shufflebeat]

Originally Posted by tadol

You can test by using a 2-3 prong adapter - my friends Hot Rod Deluxe had a pretty bad hum, but I gave him one of those and hum disappeared. He probably should have it checked out, but thats his call -

I should preface this by saying I’m in the UK and might be misunderstanding the situation…


…but,

I didn’t know what a 2-3 prong adaptor was so I had a quick web-sniff and found what I think you’re talking about.

Any device that has an earth (ground) connection does so for a reason. If the PSU is naturally 2-pin it’s because it’s double insulated so an earth connection isn’t required. In the situation that a device’s case becomes live then that current will want to flow to earth and if there’s no appropriate path then you become the ground connection, which can be messy, and death-y.

If your pedals need isolated supplies then get them and save on funeral costs.

Again - I may be reading this all wrong.

[Andyfreddy]

Thanks all.

FYI, I got a Roland/Boss brand pad 120 power adapter, and that stopped the hum!

[tinnitus]

I had a similar problem once and solved it by getting everything plugged into the same outlet. Separate circuits would be a good first possible culprit to rule out.