Need an all metal low EMI chassis to replace new Fractal :(

Kevin Parsons · 23 May 2018 at 18:21

Hi guys. Trying to find a low EMI all metal PC case for my music studio. I currently have a Fractal Design R6 brand new, but my build is interfering with guitar pickups. I'm pretty sure it's because half of the thing is plastic and providing little resilience to EMI. Wondering if anyone has any good ideas.

Ive got a feeling i might have to venture into server territory here as everything seems windowed or partially plastic these days! Any nice ideas?

hughythomas · 25 May 2018 at 10:34

Yup, get your studio grounded mate. I run a plastic Fractal (Define S) and a RME FF802 via USB and have no issues.

Once I got a sparky in to put a copper rod in the ground outside and attach up my place (its an external building) all my interference issues went away.

I run a studio full time - if you want some further help as I don't come on here that much feel free to trust me and I'll be happy to offer some advice.

Kevin Parsons · 25 May 2018 at 13:45

Thanks for the advice Tom! You've got me thinking now. I wonder how i can test the ground quality of the house. Maybe the EMI is getting stuck. I did however test this rig on a feed from the garage and it continued to emit, not sure if that would make a difference though if its all connected back to the same ground anyway.

I figure there should be a ground rod coming off my electric box- i shall have a little look tonight.

bremen1874 · 25 May 2018 at 14:14

I've always assumed that you don't see commercially built PCs in Windowed cases is because they'd fail the required EMI tests.

hughythomas · 26 May 2018 at 15:02

I run a Fractal with a window in my recording studio. I work full time in this environment and never have any issues.

Check the rod man - this made a massive difference to my recordings so am speaking from personal experience!

bremen1874 · 26 May 2018 at 15:50

There’s a good chance that there isn’t a rod at all. Every place I’ve lived has been earthed via the incoming supply cable.

Kevin Parsons · 29 May 2018 at 13:14

Yeah I just had a brief look at my system, PMC or TNC s. Looks like modern homes are earthed like that. Might see if it's an easy system to change.

Kevin Parsons · 4 Jun 2018 at 14:42

Update- installed an earth rod on the weekend as a test. Going to rig it up to the studio and if it makes any difference i'll get a professional install done.

Also, i moved my motherboard and psu into a steel case- still screams at my guitar

bremen1874 · 4 Jun 2018 at 14:48

Have you established whether the interference is travelling over the mains or via another path?

Kevin Parsons · 4 Jun 2018 at 14:53

I've got a bad feeling its just a noisy squeaky emi hive of a mobo, unless it's the seasonic psu (tried two of those, and seasonic is meant to be pretty good). Annoying as it was bought new last year. ASUS B350 prime.

As soon as i solve it i'll be sure to post up.

Kevin Parsons · 8 Jun 2018 at 20:16

Directly grounding the rig to a pole in the garden has made no difference. Had a brain wave that the d15 i have (huge chunk of metal heatsink) could be an antenna next up, so grounded that too. Nothing.

Next options:

Power conditioner (in the hope of mains causing it)
New mobo
Different brand of PSU to seasonic/corsair. (tried a corsair and it made no difference.)

The emi is massive around the PSU but im thinking perhaps the board could be to blame for it. It just seems like it has some kind of internal ground loop from hell going on.

LuckyBenski · 8 Jun 2018 at 21:23

I'm wondering if you've checked how well shielded your guitar is, and if your amp/desk are grounded properly.

I'm a guitar tech and while I've not had to confront many persistent noise issues (always worked out of a shop), wiring guitar from best principles and shielding them well has generally kept customers happy. If it's a Strat there's a certain amount of unavoidable noise.

Kevin Parsons · 9 Jun 2018 at 01:09

Thanks benski. 15 of the buggers and they all do it! (All stock shielding mind) Through my axe FX III on its own headphone amp

Guessing no shielding is gonna help them though given the 2 to 3 giant antennas sticking out of the middle of em' haha.

LuckyBenski · 9 Jun 2018 at 10:44

Kevin Parsons said:
Thanks benski. 15 of the buggers and they all do it! (All stock shielding mind) Through my axe FX III on its own headphone amp Guessing no shielding is gonna help them though given the 2 to 3 giant antennas sticking out of the middle of em' haha.

Damn. The only thing I can think of is if you have a GPU drawing lots of power, but that's unlikely. Does the noise change based on placement of the guitar or the AxeFX?

Kei · 11 Jun 2018 at 09:07

Have you tried using the axe fx with only the guitar connected no usb and a set of headphones? (If it’ll let you) it’s most likely going to be the usb cable or whatever means you link the axe fx to your pc that is creating this issue.

It sounds remarkably like a ground loop causing the shield within the signal cable to act as the antenna for rfi. Isolation transformers are an alternative. I have to use these on mine if I use any form of direct copper link between my pc and any of my audio equipment.

Some good information available here.

Kevin Parsons · 18 Jun 2018 at 15:46

Thanks Kei. I have indeed tested that to hopefully isolate the two, issue exists still so i believe it is pure EMI emission from the computer. Also tested for voltage between my ground and neutral on the mains and that is looking really good too.

I reckon a lot of it is to do with switching PSU's or the Mobo dumping loads of interference down the PSU rails.

Also, another little update on this issue- i borrowed a small form factor HP to test in the same location. Barely interfered at all, almost zero unless i got the pickups very close to it. Couldnt test my seasonic PSU on it though has it has a bloody annoying proprietary cpu power pin. My final 2 stages of elimination for the rig are testing with a UPS this week followed by a more expensive motherboard.

I'm beginning to wonder if i'm missing a fundamental step when i build PC's!

Edit: speaking of which. I do tend to let my cabling run a bit wild sometimes. I might have a go at cable tying my PSU cables away from everything possible.

Kei said:
Have you tried using the axe fx with only the guitar connected no usb and a set of headphones? (If it’ll let you) it’s most likely going to be the usb cable or whatever means you link the axe fx to your pc that is creating this issue.

It sounds remarkably like a ground loop causing the shield within the signal cable to act as the antenna for rfi. Isolation transformers are an alternative. I have to use these on mine if I use any form of direct copper link between my pc and any of my audio equipment.

Some good information available here.

Kevin Parsons · 29 Jun 2018 at 13:20

Little update for you googlers who hit this one day.

A UPS did nothing to solve the problem, so it is contained EMI. However, a new x470 motherboard has cut this by 75%, now a perfectly manageable level. I'm still currently tweaking out settings, but i believe it is motherboard VRM stages & coil whine causing this issue. I'm trying to get everything running flat out, looking at spread spectrums and ironing out as much as possible to provide constant voltage so that my pickups don't amplify these fluctuations.

I did believe the graphics card was having a part to play as well as the noise is induced on mouse and window movement, however from certain research i'm inclined to think it is CPU related.