Electrical Buzzing Sound

Hey there, a while ago I made a thread on this very forum asking for advice concerning a good microphone, I received so much help it really made a huge difference to my purchase and raised my awareness of recording equipment in general.

When I can replicate this next I will; I’ll record a sound clip of it.

Basically, sometimes I’ll go to record in Audacity or any audio program, Ventrilo, Skype, etc… And there’ll be a buzzing sound in the background, my voice will still transmit but the volume will be low, then I’ll unplug the Preamp and plug it back in and it’ll be fine, crystal.

EDIT - LINK : http://www.megaupload.com/?d=9MNJ40LR

I’m not sure why this is, is it because I turn it on before the PC is on? Is it because I leave it plugged in for long periods of time? Is it because it’s a round 2-pin plug using a 2-pin to 3-pin adapter? I’d love to know.


For those who can’t wait for Mega-slow upload I’ve attached an mp3 copy …

The buzzing is mains hum (50Hz type).

If a Mono jack-plug is (incorrectly) inserted into a Stereo socket an incorrect connection occurs between the sleeve and the ring which could be the source of your intermittent buzzing which is resolved/caused by plugging/unplugging .
audiojacks - Mono Stereo.jpg

Actually when I unplug it, it’s the AC I’m unplugging, not the jack, you may have meant that anyway, but I’m just making sure.

EDIT - Oh right, I misread what you meant :stuck_out_tongue:.

It’s an XLR - 1/4" MONO jack, with one ring, which is being inserted into a 1/4" to 1/8" STEREO adapter, which is then going into the Line In on my sound card.

Would the problem be remedied by using a mono adapter?


No my mistake, I thought you were unplugging the audio connections (jackplugs).

Yes, using a 2-pin mains (AC) plug can make a difference as it doesn’t have an earth pin which 3-pin plugs have.

Earth (a.k.a. “ground”) connections (or lack of them) can be a source of mains hum …

Low current wiring is particularly susceptible to ground loops. If two pieces of audio equipment are plugged into different power outlets, there will often be a difference in their respective ground potentials. If a signal is passed from one to the other via an audio connection with the ground wire intact, this potential difference causes a spurious current through the cables, creating an audible buzz at the AC mains base frequency (50 or 60 Hz) and the harmonics thereof (120 Hz, 240 Hz, and so on), called mains hum.


A floating ground circuit is a circuit in which the ground is not used … not connected to a grounding point [> e.g. 2-pin mains plug> ]. Ground loops can form when equipment with floating grounds are connected to properly grounded equipment [> e.g. 3- pin mains plug> ], and results in a current traveling between the two devices.


If you are using any outboard (externally powered) audio hardware, make sure all the equipment is plugged into the same power strip. Grounding issues can cause ground loops, which will appear in your recording as a hum.


NB: the earth (ground) connection is a safety feature, do not disconnect it.

You might do well with a little alcohol-based glass cleaner or vodka and a paper towel. You should never touch the electrical connections on audio plugs. The natural oils on your skin stick and start to degrade the connection. You get enough oil on the shield connection and there’s your hum protection in the dust bin. Scrub all the plugs and put them back twice.


So sorry for the extremely late reply - a lot has gone on, and for a while I wasn’t having troubles with the microphone.

two days ago I rubbed the plugs (the 2 pin and the 2pin-3pin adapter) in a mix of Isopropyl Alcohol 60% and Water 40%, I plugged them back in and I still have the buzzing, it comes and it goes, it fades in and fades out…

As well as having another problem, sometimes my mic can just cut out all together, or sometimes my volume will be really really low and I’ll have to tap the microphone or make a loud noise for it to come back. I’m really not sure why this is happening, and I honestly feel like there is no easy remedy to this.


The first solution is to ensure that all metal chassis are interconnected, then connected to the electrical distribution system at one point (often referred to as a “single-point ground”). The next solution is to have shielded cables for the low currents, with the shield connected only at one end (this, however, increases the possibility of radio frequency interference (RF) since the shield may act as an antenna). Another solution is to use isolation transformers, opto-isolators or baluns to avoid a direct electrical connection between the different grounds. However, bandwidth of such is of consideration. The better isolation transformers have grounded shields between the two sets of windings.


I don’t understand any of this, because I’m not an electrical engineer. It doesn’t make sense to me.

And I don’t mean to sound ignorant, but it is just flying right past my head.

Who made the microphone and what is it?

You’re on a Windows machine, right? Sound Insanity on a Windows machine can be caused by Windows trying to “help” you with sound management. Make sure the extra services are turned off.

Windows Enhanced Sound

I’m just reading through this again. In general, you can’t buy this…


I had to make mine and I’ve never seen one for sale. You can certainly buy one of those with an extra tiny ring on the plug. That can cause all sorts of problems because, without going all techie on you, the microphone is sending one show down all three wires. This is high-end, professional/broadcast technology. The adapter and computer are assuming two different shows on those three wires.

Like the plug on this cable.


That’s a stereo cable, with Left and Right shows – different shows.

The broadcast technology use automatic error correction, hum suppression, and top quality shielding. This is the kind of cable that can go hundreds of feet on a rock concert stage without causing problems.

The computer microphone connection has no error correction, poor hum suppression, and marginal shielding. It was never intended to travel much over one or two meters/six feet.

Did I hit it?

I’m going to see if I can find somebody making the proper adapter.


Hi All,
The 3.5mm Mini Jack plugs/connectors on a PC soundcard or a Laptop are all STEREO connectors and not balanced like in pro-audio equipment.
Stereo meaning a left and right channel. Thus Tip=Left channel, Ring=Right channel, Shield= Ground(both channels chare the shield).

Where the problem of a electrical hum starts is that the ground/shield of the Mini Jack is also connected to the ground of the DC supply.
With a laptop you can run of battery power while you record, but what to do with a PC?

The solution is to use a isolation transformer. Whirlwind make some but there are other brands as well.

I setup for recordings as follows:

Microphone—>(balanced female XLR-male XLR cable)—>Mixing console Main L+R(XLR balanced output) —>(balanced female XLR- male XLR cable)—>Stereo(left and right) Isolation transformer(XLR balanced input and Mini Jack/RCA unbalanced output)—>(Stereo male Mini Jack- male Mini Jack cable)—>Laptop

With this setup I can record stereo sound, or set the “Pan” on the mixing console to left and right.
So I set the vocal to left and the instrument to right, on the monitors the musician gets the mix but I can choose what to record, just vocal or instrument or both.


Hope this help.