Analog to digital eliminate electrical noise

I'm starting to convert some analog video to digital. During actual recording, I'm finding that I'm getting a kind of a consistent slight buzzing sound. It doesn't completely drown out the audio, but it's loud enough to be annoying. On playback on the finished digital end, the same consistent buzzing sound is still there. I've read this can possibly be caused by ungrounded electrical outlets? Any idea if that could be the cause? Or is there another possible cause (and solution) for this buzzing sound? If it matters, the video converter I'm using is the El Gato video capture device (not the gaming one, just for regular video).

60 hz does make an audible buzz.

try plugging your stuff directly into the wall, no power strips or extension cords.

if that doesn't work, see if you can isolate the frequency and filter it out. I'm sure there must be digital audio filter software out there free that will eliminate one or a small range of frequencies easy.

Yep, my vcr and laptop are directly into separate outlets using no extension cords or power strips.

I should have noted this initially, I think what I'm experiencing is called ground loop? Sounds like some folks with guitar amps among others, encounter such a problem?

Robbie, ideally I'd like to take care of this on the front end, so I don't have to get into digitally filtering it out of the finished product.

if you are getting a ground loop.. you need a ground lifter. Basically an old fashioned adaptor for putting grounded plugs into sockets without the ground hole. We use them in audio all the time just for that reason

I don't think I've ever seen a grounded VCR so that kinda eliminates a ground loop to my understanding. Have you verified the VCR is putting out clean audio (plug it into a TV or sound system)? Being a VCR, and thus probably being 10+ years old at this point, it might have a blown filter capacitor (the biggest aluminum can(s)) in the power supply letting 60hz noise through.

Okay, in keeping with my pattern of guessing some bizarre thing that totally fails the "simplest explanation" test...

You mentioned separate outlets. As in possibly on separate circuits? On old houses, I've had a couple of really weird "what do you mean there's a voltage differential between these two things?" instances...

Can you plug them both into the same outlet (or, you know, the same fixture)?

Like I said, there's probably a simpler answer...

BrokenYugo wrote: I don't think I've ever seen a grounded VCR so that kinda eliminates a ground loop to my understanding. Have you verified the VCR is putting out clean audio (plug it into a TV or sound system)? Being a VCR, and thus probably being 10+ years old at this point, it might have a blown filter capacitor (the biggest aluminum can(s)) in the power supply letting 60hz noise through.

I have to admit the vcr itself didn't even cross my mind at first. My newest unit, which I was using, I bought new in '08 or '09. I've used it sparingly over the years, but like a low mileage, well kept car, one would not expect much trouble right? Luckily I have two other vcr's which funny are both probably close to 20 years old. Well one of them, the trusty old Hitachi, is playing its current tape just fine, with no buzzing or humming!

And Mad Machine, yes I'm using a cheater plug. An interesting point I've found, although its not really recommend by a lot of guitar players (who may also encounter the ground loop issue) using big amps, but for what I'm doing, I think I'll skate by.

Ransom wrote: Okay, in keeping with my pattern of guessing some bizarre thing that totally fails the "simplest explanation" test... You mentioned separate outlets. As in possibly on separate circuits? On old houses, I've had a couple of really weird "what do you mean there's a voltage differential between these two things?" instances... Can you plug them both into the same outlet (or, you know, the same fixture)? Like I said, there's probably a simpler answer...

This. If the two outlets are on separate circuits, and each circuit is on an opposite leg in the circuit box, they'll be out of phase. Add in any kind of ground loop and things get weird...

mad_machine wrote: if you are getting a ground loop.. you need a ground lifter. Basically an old fashioned adaptor for putting grounded plugs into sockets without the ground hole. We use them in audio all the time just for that reason

This.

Even if everything associated with your A/D conversion is on non-grounded plugs, something else on that breaker (or nearby on another breaker) could be feeding noise.

I have to fiddle with grounding/not grounding things at the theater all the time. I keep two of those ground isolators on the sound booth at all times. Some sound engineer comes in with a Mac and Qlab, I know the sound board gets one to isolate the ground. Otherwise, every time they plug in their charger, it is going to pick up the TV station's broadcast from next door and pump it through our speakers. Someone wants to run a dimmer rack for lighting, I will take it off to ground the sound board so the RF from the rack has a place to go before the speakers.

There have been other times when things were great until someone touched the sound console and all kinds of demonic voices seemed to come from the speakers.

Just play around with grounds/not grounds and I think you'll find big differences.

I hate being that guy but I wouldn't recommend lifting grounds unless you're running GFCI outlets or really know what you're doing. It doesn't come into play often but that pin isn't there for the hell of it.

To eliminate ground loops, ground everything to the same point. Not saying it would cure your problem, but all the equipment should have been plugged into the same power strip. A separate wire from the equipment chassis to ground may also help. And is the house wire ground really grounded?

I suspect this is a problem with the VCR, but if it is really some grounding issue, just run your laptop iff its battery and see if there is any change.