Have you ever received an electric shock from your microphone or your guitar? It
may not seem like such a big deal, but it actually can be very dangerous. At the
end of this video, I'll help you determine what you need to do to fix
your equipment, but first we need to understand exactly what's happening so
that we know which piece of equipment is the culprit. But hey, if you're new here,
welcome. I've created Audio University to help you learn about audio production. If
that sounds interesting to you, subscribe below. In most cases, even though your
microphone or your guitar seems to be shocking you, the problem actually lies
in the guitar amplifier or the microphone mixer. Three things are likely
happening. Number one, your equipment is improperly grounded; two, your body is
becoming charged by that improperly grounded equipment; and three, you're touching
something that is properly grounded and your body is being discharged. The most
likely scenario is that something on the inside of your amplifier or your mixer
is malfunctioning. It's creating an electric voltage on the enclosure or the
chassis of that device. Most of these devices have safety measures in place to
allow that voltage to drain away to ground. Devices with three-pronged plugs
like this connect to the third, round prong to the chassis of the device so
that any voltage will be drained away. Using a two prong adapter or "cheater
plug" for these devices will disable this safety feature. If voltage is present on the
chassis of a device that is plugged in using one of these adapters, it will have
no place to go. This can be really dangerous, as you'll see in the following
sections. Although you may feel safely isolated from your guitar amplifier or
your mixer, that is not the case. The instrument or the microphone in your
hand is a direct connection from your body to the chassis
of that equipment. The bridge of your guitar is connected to the sleeve or
shield of your instrument cable. The sleeve of your cable also connects to
the amplifier chassis. The grill of your microphone is also connected to the
ground pin of your XLR microphone cable, which connects then to the chassis of
the microphone preamp. There's no need to fear these connections, because they're
in place as a safety measure. The problem is that
something is malfunctioning turning that safety measure into a safety hazard. When
you pick up your guitar that's connected to your ungrounded amp, any voltage
that's on the chassis of the amp will be transferred through the guitar over to
your body. Because the voltages that are being applied to your body from that
amplifier are relatively low, you may never notice this happening. However, if
you're touching the equipment and a grounded surface simultaneously, you will
definitely notice. These two diagrams might help you to understand why one of
these situations is safe and one is really dangerous. This diagram shows a
simplified image of what is happening when you touch ungrounded equipment
without touching anything else. The second you touch the ungrounded
equipment or an instrument connected to it, the voltage quickly charges your body
to its maximum capacity. You can imagine it's like filling up a balloon because
once the body is fully charged, the voltage again has nowhere else to go.
This diagram shows a much more dangerous situation. This is what happens when you
touch both ungrounded equipment and a grounded surface. The voltage from the
ungrounded chassis now has a pathway through your body and into the grounded
surface. That creates the potential for a very strong electric current to
indefinitely flow through your body. Touching a grounded surface can mean a
variety of things. You can either touch a properly grounded microphone while
holding an improperly grounded guitar or vice versa; you could be standing
barefoot on a garage or basement floor; or if there's moisture in the air from
rain your shoes or your microphone stand can become a conductor to ground. If
you're experiencing electric shock from improperly grounded equipment, I highly
recommend that you figure out what's happening and get your equipment
serviced. To test if your equipment is properly grounded, we're going to use a
multimeter. Set it to test for continuity. That's often represented by the Omega
symbol. This means that anytime there is
continuity between the red the black probe, the needle will jump. To
test this guitar amplifier for improper grounding, we're going to unplug it from
power. We'll place the first probe of the multimeter on the third ground prong of
the guitar's power plug and then we'll take the other probe of the multimeter
and place it on the input. So this input makes that needle jump, which means it is
connected to the ground prong. This input also makes the needle jump and so does
this one. So that means that all of the inputs on this guitar amp are connected
to the ground plug drain wire, which means that this guitar amp is properly
grounded. Now that you understand what's happening and which device is
responsible, what can you do to fix the problem? Well even though you should be
safe so long as you don't touch the ungrounded equipment and a grounded
surface simultaneously, I wouldn't take that risk. My recommendation would be to
take your equipment to a professional and get it serviced to meet safety
standards. I hope you got value out of this video. If you did, hit the "Like"
button and consider subscribing. Check out the website at AudioUniversityOnline.com
Thank you very much for watching and
I'll see you in the next video.