ground loop?

[Lobster11]

A friend and I are starting to experiment with a new duo thing in which I play bass and he plays "electronics." I won't bother with the details unless they turn out to be relevant, but here's the problem we're having:

I play through a pedalboard into a combo amp; he plays his stuff into a pair of monitors. So far so good -- sounds great in the room. But now we'd like to record, and are trying to figure out how to send both signals into his audio interface so he can futz with it using Ableton.

The problem is that we've tried a couple different ways to do this -- e.g. sending a signal from either my pedalboard or via a line-out from my combo amp to his recording interface -- and we always seem to be creating a ground loop. What do we need to do to prevent this?

 

[DanDBassist]

I have only one question at this time: Is everything plugged into the same outlet/strip?

 

[Lobster11]

I have only one question at this time: Is everything plugged into the same outlet/strip?

Good question. No, they are not. We figured out how to plug two of the three (my pedalboard and amp) into the same outlet, but that's different from what all his gear is plugged into. Do you think the solution might be so simple as (somehow) having everything plugged into the same outlet?

 

[DanDBassist]

Good question. No, they are not. We figured out how to plug two of the three (my pedalboard and amp) into the same outlet, but that's different from what all his gear is plugged into. Do you think the solution might be so simple as (somehow) having everything plugged into the same outlet?

Well, it's certainly worth a try.

 

[mike buzzetti]

Good question. No, they are not. We figured out how to plug two of the three (my pedalboard and amp) into the same outlet, but that's different from what all his gear is plugged into. Do you think the solution might be so simple as (somehow) having everything plugged into the same outlet?

Yep !! get a multi-outlet power strip

 

[Lobster11]

So y'all think it might be as simple as having everything being connected to the same power outlet? That might be a little messy but we could probably figure out how to do it if that would solve the problem.

 

[JRA]

So y'all think it might be as simple as having everything being connected to the same power outlet?

pretty much. as @DanDBassist said: worth a try! good luck, hope it works!

 

[JKos]

If that doesn’t work, get a simple transformer-based DI to go between your gear and his interface.

 

[seamonkey]

Here's why you can get a ground loop, and another way to test it if you have or can borrow a clamp meter

The sensitivity of the clamp meter can be increased by looping the xlr cable a few times around the clamp. Divide the reading by how many times you loop.

 

[Lobster11]

Here's why you can get a ground loop, and another way to test it if you have or can borrow a clamp meter

View attachment 4607736

The sensitivity of the clamp meter can be increased by looping the xlr cable a few times around the clamp. Divide the reading by how many times you loop.

So this reminds me of another detail. I have a few possible options for sending my bass signal to his recording device:

1. I have an old Sansamp pedal with an XLR DI out that I can send to the recording interface.

2. The Sansamp is one of a couple of pedals that could send a regular instrument-level output (parallel to the signal going to my amp) to the recording interface.

3. I could use the line-out connection on my amp to send a regular instrument-level output to the recording interface.

Pros and cons regarding these options? Or does it just depend on what is plugged into which power outlets?

 

[LukeSlywalker]

Other than trying everything in to same outlet, another fix would be adding a DI (like your sans amp) into your signal path and hitting the ground lift button on it. I keep a Radial JDI in my gig bag for these occasions

 

[DanDBassist]

Usually a two outlet 3 prong wall receptacle should be grounded the same so you should be able to use both to operate 2 strips and not have a ground loop if you need extra outlets. That is if all the outlets in the strips are properly wired.
By ground loop you mean there is hum? I have heard of outlets which have a long distance between them can result in a voltage difference which could cause some problems. I'm just batting blindly here but hope you fix this. Good luck

 

[seamonkey]

So this reminds me of another detail. I have a few possible options for sending my bass signal to his recording device:

1. I have an old Sansamp pedal with an XLR DI out that I can send to the recording interface.

2. The Sansamp is one of a couple of pedals that could send a regular instrument-level output (parallel to the signal going to my amp) to the recording interface.

3. I could use the line-out connection on my amp to send a regular instrument-level output to the recording interface.

Pros and cons regarding these options? Or does it just depend on what is plugged into which power outlets?

IMHO - The least amount of "distance" between your bass and the interface is usually best. Like plugin straight into the interface.

Most modern interfaces have a direct stereo monitor out so you and others can listen to yourselves with zero or low latency. The left or right monitor out can go into your pedals or amps so you get your sound while recording. The other left/right is for your buddy.

After you get a good clean track then you can re-amp or use plugin to color the sound in the DAW.

It doesn't sound like fun, but amps, pedals, ... can be noisy and it's hard to take the noise out afterwards.

 

[rufus.K]

Try it all from the same receptacle. Use only one device with a breaker (like a common power strip has).
If you use the SansAmp via batteries it should also help. Mine has a ground lift switch, which is then also worth trying.

 

[DanAdams]

I'm not recommending this as an permanent fix, but sometimes ya gotta do what ya gotta do.
at least have one in your kit to trouble shoot the buzz before really fixing it.

In an old apartment I once ran my own ground line off one of these orange things, out a window, and to a ground rod I drove into the earth.

 

[Lobster11]

Thanks for all the replies. It sounds like the first two things to try are (1) plugging everything into one outlet and/or (2) running the Sansamp/DI on battery power. Those are the two ideas we had, too (thanks for confirming), but we didn't have the power strip(s) or fresh 9V battery we needed to try either. We probably won't get to do this until end of next week, but I'll be sure to report the results here afterwards.

BTW, I did try the ground lift switch on the Sansamp but it seemed to have no effect. I'll keep that in mind, though, in case it proves helpful when we change things up.

 

[iiipopes]

What DanAdams said. Recently I mixed sound for a friend's band. At sound check, hum, hum, hum, everything seemed to have a ground loop (old building, re-worked mains, many cross-wired circuits). I took a couple of these 3-to-2 prong adapters as a ground lift, making sure everything was still grounded as some point in the mains and signal chains. Problem solved.

I got this idea from when I ran a rack tuner thirty-some years ago. I got my new tuner, installed it, ran all cables according to directions, and hum, hum, hum. After trying several variations on the signal wiring, and knowing everything was actually grounded through the system, I put a 3-to-2 adaptor on the tuner power cord. Hum vanished.

 

[Lobster11]

I'm not recommending this as an permanent fix, but sometimes ya gotta do what ya gotta do.
at least have one in your kit to trouble shoot the buzz before really fixing it.
View attachment 4608350
In an old apartment I once ran my own ground line off one of these orange things, out a window, and to a ground rod I drove into the earth.

What DanAdams said. Recently I mixed sound for a friend's band. At sound check, hum, hum, hum, everything seemed to have a ground loop (old building, re-worked mains, many cross-wired circuits). I took a couple of these 3-to-2 prong adapters as a ground lift, making sure everything was still grounded as some point in the mains and signal chains. Problem solved.

I got this idea from when I ran a rack tuner thirty-some years ago. I got my new tuner, installed it, ran all cables according to directions, and hum, hum, hum. After trying several variations on the signal wiring, and knowing everything was actually grounded through the system, I put a 3-to-2 adaptor on the tuner power cord. Hum vanished.

We're doing this in a fairly new house, so I think it is unlikely to be a problem with the electrical system as might be the case in an old house or building.

Plus, those things make me nervous. I wouldn't use one except in a real emergency.

 

[Frank Tuesday]

We're doing this in a fairly new house, so I think it is unlikely to be a problem with the electrical system as might be the case in an old house or building.

Plus, those things make me nervous. I wouldn't use one except in a real emergency.

If you're nervous about using a ground lift adapter, you can always use an inline GFCI between the gear and the adapter. if there is any current leakage it will switch off. And they don't require ground to work.

 

[Bob_Ross]

Way more comprehensive than most musicians will ever need, but imho this white paper is mandatory reading for anyone who uses AC powered audio equipment:

https://www.jensen-transformers.com/wp-content/uploads/2014/08/generic-seminar.pdf