Highlighted
Contributor - Level 2

Noise from my Computer

Hi everyone. I am connecting the G System using the 4 cable method. The only exception is I have my amp's return going into my PC and the PC input going back into the G out. I am experiencing significant higher pitch noise and interference. Almost like the hard drive or something. Laird tried to assist in the past, but still have the same problem. I have all balanced cables except for the 2 going into the PC.
The weird thing is that when I plug in the cord that normally goes into the G out into my guitar, there is no noise (and no distortion because I think the preamp is bypassed). As soon as I plug this cord into the G-Out, the loud noise starts immediately. It seems to be how the amp, PC, and G are interacting.

Any suggestions?????? I already tried the Ebtech that Laird recommended and nothing.
Tags (1)
cvor Contributor - Level 2 2008-10-21

2008-10-21

Noise from my Computer

Hi everyone. I am connecting the G System using the 4 cable method. The only exception is I have my amp's return going into my PC and the PC input going back into the G out. I am experiencing significant higher pitch noise and interference. Almost like the hard drive or something. Laird tried to assist in the past, but still have the same problem. I have all balanced cables except for the 2 going into the PC.
The weird thing is that when I plug in the cord that normally goes into the G out into my guitar, there is no noise (and no distortion because I think the preamp is bypassed). As soon as I plug this cord into the G-Out, the loud noise starts immediately. It seems to be how the amp, PC, and G are interacting.

Any suggestions?????? I already tried the Ebtech that Laird recommended and nothing.

  • 0 Kudos
  • 9 Replies
  • Reply
Rob Contributor - Level 2
Contributor - Level 2

Re: Noise from my Computer

Is your PC grounded? If yes, try using a wall outlet without a ground for the PC. Looks like a ground loop with the pc...
Fender telecaster plus USA with Kinman Pickups, Gibson ES335 2010 Custom Reissue, 1966 Fender Bassman, Lehle Sunday driver, TC G-System, Waiboer Engineering tube fx-loop, TC Nova Drive, Boss BD2, Boss OS2, Suhr Rufus, Ernie Ball Volume pedals for Exp & Vol. Marshall 2x12". 2 Redbox HK.
Super Contributor - Level 2

Re: Noise from my Computer

I disagree with the ground loop idea. I think that it is certainly possible, but ground loops tend to be related to power, at 50Hz or 60Hz, which gives a low frequency hum or buzz.

Also, running with a "cheater plug" (no chassis ground) is dangerous. Ground faults can kill.

I don't know what you're using for a PC card (sound card, recording card, or just motherboard audio) but PC cards tend to be pretty noisy, especially if you are running long single-ended cables near them. One trick is to put a "choke" on the cables. Chokes are those cylinder-things that come with some audio equipment and get wrapped around the cable. They are essentially an RF filter.

Another alternative is to get a sound card with an external audio unit.

At the very least, keep the cables away from the PC as much as possible. If you use a 20' guitar cable and coil most of it on the floor right behind the PC, you have created an antenna. Keep the cables short and run them straight away from the PC.
G System Black iB mod
Contributor - Level 2

Re: Noise from my Computer

Thanks for your advice. I wil try out the chokes. Do you think these are the right ones??
http://www.radioshack.com/sm-snap-together-ferrite-choke-core--pi-2103222.html
I guess I should get 4 --- 2 for each cord connected to the PC? Or should I get more?

I have a MAudio Delta 1010LT PCI card and ASUS p5Wdg2 mobo. I have my PC mounted in a metal 4u rack casing.

I'm trying to take certain components out of the mix. I tried it with just the G and my Roland GI-20 Guitar Synth (without the PC) and I got a lower sounding interference. When I unplugged the GI20, the noise went away and I heard pretty normal and acceptable amp noise that you would hear from a high gain amp. However, when I put the PC back in the mix, unplugging the GI20 made no difference whatsoever. This noise is really bad and I wouldn't really be able to play somewhere with it like this - at least with the PC or Gi20. I should probably try it out in a different house too and see if I get the same noise.

Thanks again for the help.
Super Contributor - Level 2

Re: Noise from my Computer

Those chokes should work as well as any. I would start with one to try to isolate the noise source. Try it in different locations on each cable to see if you can find a sweet spot. It may only be required on one cable, or it may help to have one on each. I doubt it will do any good to have more than one on any cable.

I am curious what exactly you are trying to take out of "the mix". My experience with PCs in the audio path is that they crash at exactly the wrong time. If there's another way (filter, equalizer, stand-alone processor, whatever) I'd tend to go that way. Kill 2 birds with one stone.

Just for fun, what happens if you hook up the PC to the amp WITHOUT the G system? I assume your setup is:

Guitar -> Gsystem input
Gsystem Insert send -> Amp input
Amp effects send -> G system Insert return
G system out -> PC sound card line input
PC sound card line output -> Amp effects return

Is this correct? If not, please list your setup.

Try:
Guitar -> amp in
AMp effects send -> Pc card line in
PC Card line out -> Amp effects return

Noisy?
G System Black iB mod
Contributor - Level 2

Re: Noise from my Computer

When I said take out of the mix, I just meant unplug the device from the chain. My set up is as you describe except I plug the G in into my GI20 Guitar Synth out.

I did some further messing around along the same lines...

When the PC is in the chain without the G-Sys, there is no noise to speak of. When I introduce the GI20 Guitar Synth, there is the high pitch noise.
When the G-Sys is in the loop without the PC, there is some considerable noise but it's not extreme. When I plug in the GI20, there is that significant noise again.
The GI20 seems to be the culprit for the high frequency noise but the G surely is contributing or amplifying it further.
Contributor - Level 2

Re: Noise from my Computer

The GI20 is connected by USB to a USB hub which is then of course connected to my PC USB port. I wonder if that has any thing to do with it. Also, I leave the GI20 on constantly (because when I turn it off and back on it sometimes asks me to reinstall drivers) so I wonder if something may have fried it.
I've taken my G to gigs and have no noise from it. My house seems to factor in here for this aspect of it.

I will try the chokes and see if that helps. I may even have one laying around somewhere.
Contributor - Level 2

Re: Noise from my Computer

Now that I try again, the interference is bad even without the GI20 in the chain and when using the GI20, it makes it only a hair worse. This is the opposite of yesterday. Yesterday, the GI20 set off the noise. However, when I take the PC out of the chain and leave just the G, it is a little noisy but no biggie. But when the GI20 is added (with the PC still not in the chain), there is the loud noise again.

The PC remains quiet though when it is in my amps effects loop by itself.
Super Contributor - Level 2

Re: Noise from my Computer

I couldn't figure out how the heck you send a MIDI output to the G input, so I read up on the GI20. Now I think I get it. Are you running the guitar output from the GI20 into the G system instrument input? Are you also using the GI20 to control a PC synth card via MIDI that you inject into the Gsystem effects loop?

If so, then you may be getting digital feedthru inside the GI20 to its guitar out. Putting a choke on that cable might help.

You also may be getting feedthrough in the multipin cable connected between your guitar and the GI20. It may be as simple as a bad cable shield or ground connection. A new cable would fix that.
G System Black iB mod
Contributor - Level 2

Re: Noise from my Computer

I am running the guitar output from the GI20 into the G system instrument input. The GI-20 connects to the PC via a USB cable --- no Midi cable necessary. It transmits the MIDI info via the USB cable.

As far as the multipin cable from the GI20 into the guitar, believe it or not, this noise occurs when the GI20 is totally powered off. I forgot when I tested it today that the GI20 was totally powered off. And also when I was messing around today, as described above, the loud interference occurred without the GI20 even in the chain. When I tried today with the GI20 in the chain (even when powered off), the interference is the same loud level but at a higher pitch.