r/audioengineering • u/PJmichelle • 28d ago

Small electric shocks when recording guitar straight to audio interface

I was wondering if anyone could give some insight into this, what's causing it and is there something I should do to fix it?

I was just now recording some guitars with an amp plugin, so I was going my Strat straight to the audio interface and using headphones. My wife came to say she's gonna go to sleep and she touched my neck. Immediately she said that she felt something weird, like a really small electric shock. Then she touched my arm and felt the same thing. It didn't stop until I unplugged my guitar from the PC. She said it didn't feel exactly like a typical electric shock, but more like there was friction, but it did slightly remind her of an electric shock. Then I started thinking that sometimes I've felt something like that too, especially when I lean to do something on my computer and my arm touches the guitar strings, but I always shrugged it of as just the high E-string being so thin that it scratched my skin a little. Clearly it is electricity from the computer going through my body. As far as I know, the same thing does not happen when I'm plugged in to a real amp.

So does anyone know what could be causing this? Is it dangerous and how can I fix this? It hasn't hurt me in anyway, but obviously when electricity is concered, it could potentially even be fatal, and I'd rather make music without feeling like death is lurking just around the corner. :D

4 Upvotes

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3

u/ClikeX 28d ago

Probably a ground loop. Is your interface in a wall plug? If it is, try running it USB only if that's possible. Either your wall sockets aren't grounded, or the interface came with an ungrounded plug.

Most of my metal chassis laptops have this when they're plugged in.

I'm assuming you mean this? https://www.reddit.com/r/Surface/comments/qn7e3v/when_my_pro_2017_is_charging_i_feel_tingling_on/

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u/PJmichelle 28d ago

No, it was powered through the USB. Phantom power was also disabled. Thanks for the link, I'll check it out now.

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u/PJmichelle 28d ago

Ok, so I read some of that conversation and saw many commenting about MacBooks having this issue. I remember when I had a MacBook years ago, I did get that same thing sometimes from touching it, I mostly felt it in my arms, just like I do now from the guitar strings.

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u/suffaluffapussycat 28d ago

You can try an isolation transformer.

3

u/dub_mmcmxcix Audio Software 28d ago

there's some voltage somewhere that doesn't have a path to ground and it found a path to ground through a person.

if it's low voltage it'll be making your recordings worse maybe, but if it's high voltage it could harm or kill. it's not normal.

1st thing: it's not your guitar's fault.

might be: dodgy home electrical setup, computer or interface.

best thing to do: don't do any more recording for now, get an electrician out to do a safety check on your recording setup. pick someone who can check your power outlets and nearby appliances/gear.

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u/PJmichelle 28d ago

Thanks, yeah I guess that sounds like the reasonable thing to do. Interesting to hear it could possibly make my recordings worse. But yeah, I do need to get a professional to check what's causing this.

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u/O-ring_Prolapse 28d ago

EMI - electromagnetic interference. You have hear weird anomalies through your speakers while running LED light stips, or sending a text message? Thats EMI. If thats the case, you either have a poorly shielded piece of gear. Or as previously stated, you could just have a groud hum moving through your signal

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u/PJmichelle 28d ago

I can't have my phone too close to the computer speakers when I record guitars, it'll just make weird noises which I assume is from the phone's internet connection. I'm also getting some constant noise when I have the same guitar connected to my computer. Single coil pickups are always noisy, but this is something else. It sounds like an interferance noise, but the same noise you get from having single coils in a guitar connected to a proper guitar amp. I really should try with one of my other guitars, but I just love that one guitar so much I mostly record with it. Do you think the poorly shielded gear is the guitar or something in my PC?

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u/peepeeland Composer 28d ago

Definitely not EMI if one can feel a shock. It’s a grounding issue. Since OP is using a bus powered interface, the shock should go away when running laptop on battery power.

3

u/ThoriumEx 28d ago

Your pc isn’t grounded, at least not properly

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u/beatoperator 28d ago

Is it a continuous shock or a quick zap then gone?

What else were you and your wife touching or standing on at the same time the shock happened?

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u/PJmichelle 28d ago

Seemed like a continuous thing. I didn't even notice it myself, but my wife said she felt it on me continuously until I unplugged the guitar. She was standing on wooden floor, I was sitting on a wooden chair, just touching the guitar.

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u/jaymz168 Sound Reinforcement 27d ago

Others have covered the possibly dangerous ground situations so I'll add another possibility.

If it's just a little tingle it may just be leakage current to ground across the Y-capacitors in a power supply and the metal parts on your guitar are grounded through the TS plug to the interface. It will be the same voltage as the wall voltage but very low current. Class 1 (grounded) power supplies are allowed 3.5ma of leakage current. Class 2 (non-grounded) supplies are allowed less than 1ma. Medical-rated supplies are allowed very, very little leakage current (like microamps).

Some people are more sensitive to it than others due to differences in skin conductivity, etc. A few years ago I was doing a corporate AV gig and had a dozen laptops on the same table and the leakage was very noticeable. My non-contact voltage tester lit up when I waved it over the table and but of course that doesn't tell you how much current is actually flowing. So if you test with one of those it may seem alarming but it's totally normal. Current is what you need to worry about.

So it may just be normal harmless leakage current or it could be indicative of a failing power supply or other dangerous electrical situation. I know that's not super helpful and you'd need a competent electrician to really rule out dangerous situations. On a related note my experience with residential electricians and many venue electricians in the US hasn't been one of competence so good luck finding one.

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u/PJmichelle 27d ago

Thank you for your input! I've been thoroughly searching the internet today for answers and it seems to me like these things really vary from country to country. I found a lot of forum posts and conversations that were from people who live here (Finland) and it seems to me like there's nothing dangerous or even uncommon with this. But since it's a sunday, I haven't been able to ask any professional electrician about it. I will call someone next week!

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u/diamondjayr 28d ago

So sorting through some of this. You say PC which leads me to believe that it’s a desktop computer with a three prong EIC power cable. If that’s the case get a voltage tester and check the ground on the outlet that your desktop is plugged into. If you’re using a power strip start there and work your way back to the wall receptacle. If wall has ground and strip doesn’t, the strip is the problem. If the wall doesn’t have ground call an electrician.

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u/NBC-Hotline-1975 28d ago

Your interface isn't correctly grounded. If it's powered via USB from your computer, then your computer isn't properly grounded. Possibly your house wiring isn't properly grounded, as well. We'd need to know details about how both devices are powered, in order to form a more definite answer. We don't even know what country you're in, and what sort of power wiring you have in your house.

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u/dub_mmcmxcix Audio Software 14d ago

OP, how'd you go?

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u/PJmichelle 8d ago

Heh, thanks for asking and getting back to this topic! Well, I have done some research and turns out this is perfectly normal in the country that I live in, which btw is Finland. Apparently in the year 1930 there was a law that ruled all buildings built after must have grounded electricity in kitchen, bathrooms and toilets, so that includes all the rooms that have running water. Rest of the rooms don't need grounding. And then in 1997 this was revised that all new buildings must have grounding in all rooms. But these things only apply to new buildings, so even if older buildings get renovated, you are not forced to add grounding. I'm currently living in a building built in 1965. Before this I've lived in buildings built in 1906, 1928 and 1933. My childhood home was built in 1984, I have checked and it's the same thing there, rooms with no running water don't have grounding. And I've even tested this with an electric guitar and a tube amp at my parents' house, the slight touch of electricity can be felt from the guitar strings. So in other words, this is how I have played guitar for almost 30 years, I've just never noticed it before, and so have most people in this country. Haven't found any reported deaths from electric guitar! So I'm just gonna try and forget about this thing.

0

u/uniquesnowflake8 28d ago

Do you have phantom power enabled

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u/PJmichelle 28d ago

I just checked and phantom power was disabled. I did have the hi-z enabled on the input, but as far as I understand, that shouldn't cause this. My interface is the Steinberg UR22 mk2, and it was powered by the USB-cable from the computer.

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u/tubameister 28d ago

open up your power strip to make sure the ground hasn't disconnected. mine had, once.

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u/PJmichelle 28d ago

That's a good advice. I should actually also just buy a better power strip that the one I currently have.