Noise caused by PC's in single coil guitar pickups - are the current crop of motherboards any better?

[Gary_W]

Hi,

When I built my current PC 3 years back, I had pretty awful noise vs. my previous PC when playing guitar near it. Same flatscreen monitor, same guitar, same (decent) leads, same mains sockets etc. I did a thread on this at the time as the noise heard most was from the hard drive / moving the mouse around the screen.

Turning off C1 in the BIOS improved this a lot but it's still not a quiet board as far as airborne interference goes. Board is an Asus P6X58D and I've read a few on-line whinges about this being a noisy board.

I've recently bought a Kemper - it's wonderful and very, very quiet. And I've noticed that the prevailing noise now (as opposed to amp hum) is coming from the PC - it's the digital chatter stuff, not mains hum, and I only get the issue when I use a single coil guitar. I always carefully screen my guitars so, in most conditions, they hold up pretty well to airborne interference.

I'm using SPDIF from the Kemper into my Focusrite interface. I've also tried the standard monitor outputs which have a ground lift. Same digital noises. It is radiated noise - proximity of guitar to PC sorts it out as does selecting position 2 or 4 on a strat. For critical recording, I can get into a position that minimises the noise (distance plus body angle) but for a general noodle session (what I do most) then I'm sat right in front of the PC practising to Songsterr or similar and the noise is irritating. I love Strat Neck and teles so my taste is my own worst enemy here

To try and put a bit of science into the proceedings, I put my guitar 18" away from my PC and then did the same 18" away from my wife's PC. My wife's PC was much, much better - it is not whacking out anywhere near as much nonsense as mine is and was (to all intents and purposes) quiet. When you consider that her PC case is a standard cheapo and mine is a brick ****house quiet case with loads of (well earthed) metalwork that helps show what a noisy thing my PC mobo is.

Soooo - are the current crop of PC motherboards good in this regard or is it still the case that single coil fans have to sit well away? I don't overly want to do a new build / pay Scan to do it right at this time but may consider it if this will 'fix' my issue. Any other council very gladly received on this matter as well

As an aside, the Kemper is truly lovely. Just had to add that

Thanks

Gary

[Gary_W]

Just giving a gentle 'bump' here - then I'll perhaps try asking in the guitar forum section?

Hope someone can help here.

Thanks

Gary

[Martin Walker]

Hi Gary,

I suspect you're right that you'll probably get more responses in a specific guitar pickup issue in our dedicated guitar forum than here in the PC Music forum, so I'll move this thread there now but leave a link here for everyone to follow.

Once point though - I would personally record an instrument a lot further away from ANY computer than 18 inches if at all possible

Martin

[ef37a]

Hi Gary,

I suspect you're right that you'll probably get more responses in a specific guitar pickup issue in our dedicated guitar forum than here in the PC Music forum, so I'll move this thread there now but leave a link here for everyone to follow.

Once point though - I would personally record an instrument a lot further away from ANY computer than 18 inches if at all possible

Martin

+1
But if the PC case is a 100% shield and is truly earthed I doubt much of the hash is actually coming from it? I mean, people SAY it is a coruscating RF inferno in there but I have never had any bother with internal PCI sound cards.

So that leaves "breaches" to RF containment as possible culprits. VGA, usb, FW and other leads.
Once Upon a Time these cables used to sport chunky RF ferrite absorbers, often on both ends of a VGA cable. Hardly ever see them now and not at all on usb/kbd cables.

So I would try some Maplin clip on ferrites. Starting with the VGA cable and fit the ferrite as close to the PC socket as possible.

Dave.

[Gary_W]

Thanks for moving the thread and for the reply Martin - much appreciated.

I do indeed record further away than 18" but I do have a few restrictions. It's a pretty small room and it has a lot in it! One of the other things that isn't TOO far away is the main electricity meter / distribution board for the house. If I move too far back from my desk, I start to get regular mains hum from that so I have to find a very narrow sweet spot in the middle It's a bit of a bummer as I've taken all the good advice in the mag / on here regarding sound treatment for the room and I have very effective acoustic panels all round which I'm very pleased with so I like what I get out of my speakers.

I think the reason I'm noticing it more at the moment is because I've just bought the Kemper and am lost in tweak heaven. It sits on my desk and I sit right next to the desk so as I can fiddle so I'm my own worst enemy. If I'm actually committing something to disk, I can get in the Bermuda Triangle of acceptance in the room. I just had my interest piqued by the fact that my wife's PC (which is actually my old one, I spoil her rotten!) is considerably quieter than mine is. The 18" was a test to see what happened and it faired better than mine ever did. Mine is still noisy beyond that distance though, of course, the issue improves with distance. And as I know I've had noise issues before which improved, but didn't go, with the C1 state then I just wondered if this kind of thing (whacking out noise) was something isolated to a few boards / that early generation that started with the C states or whether it's still an issue these days.

Dave - thanks for the thoughts here. I do have some ferrites kicking about and will have a bash.

It SEEMS to be coming from the PC itself despite the metal cage (which is well earthed as stated). Reason I'm saying that is that if I wave the guitar under the desk towards the trailing cables at the back of the desk I get mains hum but the digital stuff is not there. But I will experiment and see how I get on.

In the meantime, any other thoughts gladly received of course.

Many thanks

Gary

[PeterOeC]

Hi Gary, Dave and Martin,
It's now 2022, and almost 9 years bas gone by since you posted the original question But I found your question using Google as I was facing similar problems as you Gary.

I'll be asking some questions and proposing some ideas - but I haven't found an optimal solution myself yet, so it's more ideas for discussion and for newcomers to try out perhaps

I've got a Desktop PC with Ableton placed by my right leg under my desk, and I've got a Mexican Fender Strat (with singlecoil pickups).
The Desktop PC is pretty old - probably around 10 years (damn, older than your original question ).

Anyway, if I play my guitar by the computer (Through a Yamaha THR30IIW - a great sounding, beginner friendly, budget Desktop amp btw!).
I also notice the humming/inference the pickups/cable picks up from the computer when turned on.
But moving away from my Desktop computer lessens the humming.

I'm writing for 3 reasons - fair enough if you don't see this, as I'm late to the party (this thread)

1: In your case (and in mine), I would try to distance myself from the computer as much as possible - you can buy pretty long cables these days for not much money. So placing the PC further away (as long cables allows) may fix your problem - talking about Display Cable/HDMI for monitor, and USB extenders for Mouse and keyboard if they're not wireless.

You may also look into Balanced TRS cables or balanced XLR cables rather than Unbalanced cables TS cables (don't know if SPDIF is balanced or unbalanced???) between your Kemper (in my case THR30IIW) and the Audio interface - here's a video explaining the difference between Balanced and Unbalanced cables: https://www.youtube.com/watch?v=leTqWEZeVM4
Supposable, balanced cables should be able to carry signals further, and be less prone to outside inference.

It could also be that perhaps a laptop could be sending out less interference? Has anyone tried this? I'm considering buying a laptop - eg. a Microsoft Surface Pro 8 or a Mac for Music production and other fun stuff - and I could imagine it using less power and therefore cause less inference? But I'm not sure.

2: Also I want to ask if you fixed the problem somehow yourself in the past 9 years? And how?

3: And again I would like to ask: Does anyone knows if the same problem occurs when using a guitar with Humbucker pickups? Like a Gibson Les Paul - would be interesting! I don't own one (yet!) so I can't test.

[Arpangel]

I don’t think there’s much you can do about this, apart from an endless search for a quiet PC and it’s not worth it, they all affect single coils in some way.
I know this well, a friend recorded here many times with his Strat, I had a live room at the time, and it was the only way we could get away from the computer noise, if he recorded in the control room it was a nightmare, things like digital outboard affected it too.
Depends what type of music you’re playing, obviously loud heavy stuff, it isn’t going to be so important, I’d just try and get as far away from the computer as possible, and don’t face it while you’re playing.

[Drew Stephenson]

Have you properly shielded the pickup cavity? If not, I'd start with that - including the underside of the scratch plate.

[Wonks]

A. You can shield the cavities in the Strat. This will cut down on the level of noise picked up. Easy to do yourself and a 30m roll of 1” or 1.25” copper shielding tape (also sold as slug repelling tape) costs about £10 from Amazon or eBay. Just make sure that it is described as having conductive adhesive.

Remove all the pots, pickups and switches from the scratchplate and cover the back with overlapping strips of tape. I then use a scalpel to cut any tape covering openings or going beyond the sides (I find it much quicker to do this than to cut each piece exactly to length but YMMV). This copper will be grounded by contact with the pots (I ignore the triangle of aluminium foil already under the pots as it is often plastic-backed and it needs to be covered by the copper).

Then line the inside of the main control cavity, making sure that the tape comes up over the edge of the control and pickup cavity rout. This copper gets grounded by contact with the pickguard copper, so run copper out to several pickguard screw holes to ensure a good contact is made (whilst keeping the copper inside the scratchplate outline so it can’t be seen).

This can also be done using screening paint instead of copper tape. A 100ml tin of Rustins G Shield paint can be found for around £10 and this will do many guitars. A bit messy to apply to pickguards without going over edges and onto the front face of the pickguard, so I now tend to paint the cavities and foil screen the pickguard.

You can find many videos on YouTube on how to do this, but beware of any that just show the foil just stopping at the top of the cavity (unless they are running a dedicated ground wire to it). Whilst it may look pretty, it’s practically useless.

I wouldn’t bother with the output jack cavity. You only get a small section of signal wire in there and having the tip of the jack socket (or plug) touch and ground against the shielding is always a problem waiting to happen unless you first cover the copper with insulating tape. But in many guitars, the rout is only just deep enough to get the jack plug inserted, and adding a layer of copper and then insulating tape can sometimes make it impossible to insert a plug.

B. You can swap to noise cancelling pickups, such as those made by Kinman, MojoTone or the latest Fender noiseless range. Or fit single-coil sized humbuckers if you don’t mind moving away from standard Strat sounds. Obviously expensive, but if you have to work in that environment, it may be the only option.

There are also dummy coils you can fit in the trem cavity which will act rather like the 2nd coil in a humbucker and add in reversed polarity noise to the pickup signal which should cancel out the noise the single coils have picked up. Never used them myself but I’ve read good reports of them.

Any hum-cancelling pickup, be it a standard humbucker or a noiseless single coil, will pick up hum if you get too close to the noise source. Too close and the strength of the noise field will vary significantly between the two pickup coils, so the noise-cancelling becomes only partial.

The further away from the noise source, the more equal the noise signal level picked up by the two coils is.

So the further away from from the noise source, the weaker that signal is and the more a humbucker will cancel the noise.

C) Some laptops can end up causing more noise problems than desktops (especially with guitars) if their PSU is double insulated and there isn’t a solid ground connection to earth somewhere in the laptop + interface + monitoring arrangement. You generally only want one solid earth connection (as two or more can cause ground loops) unless you can lift the ground connection between earthed devices. But no earth connection normally results in a lot of audio noise.

[Arpangel]

Wonks, we tried lining the cavity with all sorts of tape, yours included, it didn’t make much difference, maybe a little bit, but nothing worthwhile, there are so many variables here, it’s crazy.

[Wonks]

It can certainly help, but with the pickups sticking out of the cavity, it’s never going to be perfect. Again, the further away from the source of the noise, the better. Also avoid lights on dimmers, fluorescent lights and anything with transformers in.

[Drew Stephenson]

Wonks, we tried lining the cavity with all sorts of tape, yours included, it didn’t make much difference, maybe a little bit, but nothing worthwhile, there are so many variables here, it’s crazy.

If you've got lots of variables then you just have to be methodical and change them one at a time.

[Wonks]

And make sure that the tape or paint is connected to ground. I've seen so many guitar kit builds and guitar upgrade pictures where they've fitted tape or paint but it's not grounded because 'it looks better' or 'this was the way I saw it on a video'.

You'll never get a Strat-style single coil pickup to be anywhere near as quiet in an electrically hostile environment as a covered humbucker pickup, (such as right next to an amp or a computer) but shielding can keep it quiet in more general conditions.

[Hugh Robjohns]

Wonks, we tried lining the cavity with all sorts of tape, yours included, it didn’t make much difference...

Lining isn't enough, that metallic lining has to be grounded, and grounded to the right place. Get it wrong and it becomes another part of the aerial to capture interference rather than screen it out.

Most people think of guitar wiring in simplistic terms of DC and baseband audio signals. The reality is that the whole thing is really a radio aerial with lots of resonant circuits set up amongst the wiring which often has internal ground loops too!

[Guest]

I have found (from a totally non technical view) that angling the guitar away from all the noisy stuff can make a big difference, maybe 45 degrees.

[Arpangel]

I have found (from a totally non technical view) that angling the guitar away from all the noisy stuff can make a big difference, maybe 45 degrees.

Massive difference, that’s what we did sometimes.

[rggillespie]

I find if I turn away 180 degrees its much better but then I can't see my screen or reach the mouse! Is there any software that can fish out the hum and crackle like izotope rx perhaps. You'd record with the single coil noise and then filter it out afterwards?

[Wonks]

You can get rid if a lot of the noise that way but it’s always better to not have to do it in the first place.

A wireless keyboard doesn’t cost much at all, which should allow you to have it to hand. And you should be able to set things up so you don’t need to refer to the screen at all when recording. Glance at the screen to make sure you’re in the right place then turn, press the appropriate key and start recording.

Just remember that there were no screens to look at when Stairway or Bohemian Rhapsody were recorded, and they somehow turned out OK!