Hi guys,

I still haven't been able to solve this noise I've been getting.
One thing I have noticed since is that I'm getting some hum with my Golden Age PRE73 and DMP3. I noticed that I don't get this hum when I plug these into a different mains socket (different room).
I also had some hum with my UA Solo 610 which I've had to use the Ground Lift switch to get rid of it. I don't get this hum with my ISA One or Eureka.

All my gear is temporarily plugged into a large extension reel which has only been slightly unwound. I then have a few socket boards coming off of this reel.
This is a list of all the gear connected to the same mains socket :-

Yamaha Arius Digital Piano
PC
2 TFT monitors
Focusrite ISA One
UA Solo 610
Presonus Eureka
AE 22's + Sub
Behringer HA4700 headphone amp
Behringer BTR 2000 rack tuner

I have got a Focusrite Saffire Pro 24 DSP, M-Audio Keystation 88ES, Korg Pad Kontrol and Nano Kontrol all powered by my PC's firewire and USB ports.

I also had my PRE73 and DMP3 plugged into this board but don't at the moment because of the hum I get through these.

Any ideas what could be causing this noise?

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www.richardpenrose.com

Hi guys,

I'm still getting this problem and am unsure what to do next?

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www.richardpenrose.com

Quote Poshook:

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Buy this one

http://www.behringer.com/EN/Products/HD400.aspx

and put it between your soundcard and monitors.

best

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Ok I had one of these around which I have just tried and the noise has completely gone

Will using one of these affect the sound or accuracy of my monitors?

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www.richardpenrose.com

Yes and yes, but marginally and it's better than working with the hum, and easier than fixing the real fault!

It indicates very clearly that there is a ground loop problems with the monitors and audio and mains supply grounding arrangements and the way that interfaces with the rest of your equipment. These kinds of things are always fixable, but require careful analysis, logical thought, and step by step checking to identify the problem devices.

In the meantime, enjoy the hum-free audio!

hugh

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Technical Editor, Sound On Sound

Hi Hugh,

Thanks for the reply! The bizarre thing is I didn't have this problem originally and as far as I can tell I don't have any new gear or have moved anything around. The problem kind of appeared over night!!

I'm really confused as to what the problem is and want to get it sorted properly. I guess it's going to be a painstaking process of going through every bit of gear and lead etc

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www.richardpenrose.com

Quote Hugh Robjohns:

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Yes and yes, but marginally and it's better than working with the hum, and easier than fixing the real fault!

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How would this change the sound?

I have a pair of AE22's + Sub for my monitors.

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www.richardpenrose.com

Argh!!! The noise is starting to come back but it is much quieter this time!!!

HELP!!!!!!!!

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www.richardpenrose.com

Quote dickiefunk:

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How would this change the sound?

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It's a box with a transformer in it. Transformers inherently introduce harmonic distortion and other non-linearities to some degree, depending the transformer design, quality and signal level.

Many people like these things, often saying it sounds 'more musical' or 'more analogue'

Hugh

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Technical Editor, Sound On Sound

Quote dickiefunk:

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Argh!!! The noise is starting to come back but it is much quieter this time!!!

HELP!!!!!!!!

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Oh dear! Clearly there is something complicated going on, and diagnosing that remotely is impossible. Perhaps you can persuade fellow cornland dweller Martin Walker to assist in person, but failing that the best thing you can do is strip everything apart and start again with the cleanest, simplest system you can create, and gradually build it back up from there.

All the electrical audio equipment and computer gear should be powered from the one wall socket (single or dual wall socket), using mains boards plugged together in a star configuration radiating out from that one wall socket.

Keep power supplies away from audio cables.

Use balanced audio cables wherever possible.

hugh

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Technical Editor, Sound On Sound

One thing I have noticed is that the noise gets louder when I load Cubase 6. It then gets louder with the more plugins/vsts I load!?

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www.richardpenrose.com

Just means that computer ground noise is affecting the interface and connected equipment somehow.

There will always be noise in the computer ground system, but it shouldn't affect the interface and other equipment shouldn't be susceptible to it either.

The fact that it appears to be susceptible could be down to bad design, or a fault, or poor system wiring... or a combination of them.

hugh

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Technical Editor, Sound On Sound

Thanks for the info.

Sounds like the computer is at fault! I'm going to strip everything down tomorrow to computer, interface and monitors and see what I get!

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www.richardpenrose.com

Right well I've stripped everything down to :-

PC - Saffire Pro (no psu) - 2x TFT monitors - Acoustic Energy AE22's + AE Sub.

So far there is no noise at all

I'm going to leave everything on for an hour or two and then start plugging everything else in!

It did seem like the more strain there was on the computer, the noisier it got?

Could this be a problem with the psu in my pc?

Any ideas Martin??

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www.richardpenrose.com

It’s a ground loop - when you strip down to a simple setup and hear no noise at all then you haven’t got a ground loop, but at some stage when you plug something else in you’ll hear the noise start up. That’s the time to investigate why you’ve just created a ground loop - probably because it’s an unbalanced output from a mains-powered piece of audio gear that is itself already earthed. You can cure this either with specially modified cables, with balanced cables if the output itself is already balanced, or with a DI box.

You're not loading your PC any more when you plug other gear into the system


Martin

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YewTreeMagic

Thanks for the reply Martin.

The reason why I had concerns about the power supply is because the more strain that was on the computer the louder the noise got!?

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www.richardpenrose.com

I just moved my cables so that the audio cables are away from the power cables. When I turned the computer back on I noticed the noise had come back extremely faintly. I re-jiggled some leads and the noise went away again. Hmmm!???

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www.richardpenrose.com

Hum coming and going when you move the leads usually indicates variable impedance grounding contacts -- usually because of dirt, tarnish or loose or badly made connectors.

Hugh

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Technical Editor, Sound On Sound

Thanks Hugh.

The noise I'm getting is a high pitched whining noise.

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www.richardpenrose.com

Sorry, I was using 'hum' in the generic form. Ground loops can result in all manner of hums, buzzes, whines and whistles.

The point is that if it comes and goes when you disturb the cabling, the chances are it's because of poor ground connections on those cables.

hugh

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Technical Editor, Sound On Sound

Ok thanks.

I seem to have got rid of the noise temporarily until I get some mains sockets into my room.

I was thinking of putting maybe 10 sockets in for each piece of gear but am unsure if this is a wise thing to do now?

You mentioned earlier that everything should be run off from one mains socket and then use plug boards?

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www.richardpenrose.com

Hi, Not that i am an expert by any stretch but recently had hum issues which I put down to crap jack leads to and from my effects unit.Spent £40 on 6 cables only to find it was a dodgy kettle lead.Check you have good mains connections is my mantra!! Dave

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My head hurts!

Quote dickiefunk:

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I was thinking of putting maybe 10 sockets in for each piece of gear but am unsure if this is a wise thing to do now?

You mentioned earlier that everything should be run off from one mains socket and then use plug boards?

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I run my entire studio from one double mains socket - when I attempted to plug my MIDI keyboard controller into a more convenient mains socket on the other side of the studio I got ground loop problems, so I routed it carefully back to the plugboards that everything else was plugged in and the problem disappeared


Martin

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YewTreeMagic

Oh no!!! I thought I had temporarily sorted the problem but it's back!!

I noticed that if I wiggled the plug from my computer in the plug board the sound would stop! I tried various kettle leads and the this didn't change so today I went out and bought a new plug board.
Now the noise is there permantly regardless of whether I wiggled the plug board around!

I can't seem to track this problem down and am getting extremely frustrated!! I even stripped my system down to my computer and just the pair of AE22's and STILL the noise it there!!

Any other thoughts or suggestions!??

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www.richardpenrose.com

1) get some deoxit, and super servisol, and clean every mains cable at both ends, and all mains socketry... (probably best to turn off mains at the fuse box while doing sockets)

2) go turn every single appliance in the building off at the wall, downstairs as well as upstairs, fridges, freezers, TV's , central heating , the whole lot... so that the ONLY things connected and powered by the mains is the PC , the interface, and the speakers.



what happens?


(note, half assed "sort of do it" attempts will tell us NOTHING. )

Dare I suggest getting a leccy to look at the wall socket?..or have you tried other wall sockets? sorry if I am repeating stuff! Dave

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My head hurts!

Just turned my setup on tonight and the noise has come back!! I bought the Behringer HD400 and this sorted the issue no worries but tonight it's back and nothing has changed!!???
On top of this my Presonus Eureka is also now picking up this ground loop and wasn't before??

Any ideas???

HELP!!!!!

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www.richardpenrose.com

Just had a friend briefly pop around who's an electronics engineer to let him hear the noise I've been getting and guess what :- No high pitch whining!! So I unplugged the Behringer HD400 and guess what still no issues!!!

So the high pitch whining has gone BUT I'm now getting a popping noise with my external preamps! The popping is quite quiet and happens when my mics pick up any signal.
The external preamps I'm using are a Focusrite ISA One Digital and a Presonus Eureka. The ISA One is going into my Focusrite Saffire via the ADAT port and the Eureka is going into one of the Saffire's inputs.

I've tried all the usual trouble shooting using different leads and mics but the issue is still there!!

Any ideas?

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www.richardpenrose.com

I ask because of an "oops" I had today... is this computer connected to the Internet and, if so, is there a wireless internet router anywhere in the vicinity? I ask because I tried a reorganise today and inadvertently ending up with the router too near some audio gear.. pops etc just like you describe...

Hi Mike,

No the computer is not connected to the interent. The router is in the next room.

I'll try disconnecting this to see if this has anything to do with the problem!

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www.richardpenrose.com

It's impossible to diagnose a problem if it keeps coming and going. Clearly something about your installation is changing, or is being changed, and until you get to the bottom of that you're never going to be able to solve it.

The sensible aproach is to minimise the system as far as possible, establish whether that minimalist set up is working correctly, and then introduce another item of equipment, check again, and so on.

The popping noises you mention could be interference from wireless router, but could also be clocking errors or data sync issues with your digital interfacing, so check that carefully too.

hugh

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Technical Editor, Sound On Sound

Hi Hugh,

I'll try disconnecting the router later to see if this is having any effect.

Strangely I've not been changing things around in my setup which is why I'm baffled as to the problem!?

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www.richardpenrose.com

I've just tried unplugging the wireless router and the problem is still there

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www.richardpenrose.com

Well, then at least you know it's not that and can rule it out.

Ticks and pops on audio via a digital interface is often related to nappropriate clocking arrangements or a defective interface -- and in the case of an ADAT lightpipe connection poor quality, dirty/dusty, kinked, or overly long fibres are often to blame.
Worth checking that out.

hugh

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Technical Editor, Sound On Sound

Thanks Hugh,

I've disconnected most of my gear now. I just have my computer, interface and Presonus Eureka connected. I've unplugged my ISA One and ADAT cable.

The problem is still there so it looks like it's either my interface or my computer?

I'm borrowing someone elses laptop tonight to see if the computer is the problem!!

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www.richardpenrose.com

it's worth noting that firewire is an unbalanced protocol, and prone to collecting noise , and earth loops,


make sure all sockets and plugs are are clean , all pci cards are well earthed to the chassis, (worth cleaning the backplane plates and the back place of the pci slots to be sure that any that earth through the screw connection to the chassis are making good contact, and cables have never been kinked, or compressed under chair legs and the like....

i only recommend the high quality cables from Lindy for any length... simply because they've proven reliable, even way beyond iee1394 spec both in terms of workable length and signal reliability.


checking the computer for ground noise, is worth doing.,... things like fan motors going noisy for example, are not an obvious issue, but can be the cause of odd noises.... essentially once inside the chassis, it's often the case that there is no shielding from other noise sources also inside the chassis, like a noisy fan motor (i mean electrically.... not just acoustically)


make sure there's no build up of dust and fluff in the PSU and case in general, (this often happens when machines are kept on or near floor level..... one reason i keep my tower computers at least 8-10 inches off the ground.... and preferably more than a foot... )

Thanks for this advice.

My firewire cable is a fairly new one from Lindy.

What would you recommend I use to clean the PCI cards and leads?

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www.richardpenrose.com

note, not clean the pci card itself....... but the metal plate that it mounts with on the back of the computer.....


probably isopropyl alcohol, or de-oxit.



same for leads.

or other non lubricating contact cleaner..... (NOT ordinary super servisol )

What about this:-

http://www.maplin.co.uk/isopropyl-alcohol-28994

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www.richardpenrose.com

Ok just ordered some de-oxit.

One thing I noticed is that when I was getting the high pitch whining coming through my speakers it only happened when my interface's firewire port had made connection to my computer which makes me think that it's picking up some noise from the computer? Will give everything a thorough clean with de-oxit this weekend and check everything is making good contact!

As for the popping noise, it sounds like the popping noise I was getting when my interface wasn't clocked properly! I spoke to the tech at Focusrite this morning to double check that I wasn't having a blip and he said everything is correct.
I tried the same test through the preamps on my Saffire 24 and am still getting the same popping noise. I'm now wondering if my Saffire may have developed a fault or my firewire card?

I was hoping to try a different computer last night but that fell through and will be borrowing it over the weekend. Hopefully this will reveal a little more as to the culprit

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www.richardpenrose.com

Man things are just getting stranger here by the minute!!

I just tried an acoustic guitar into the DI of my Eureka and it sounded terrible. It sounded very thin, tinny and was ever so slightly distorting!!

I did all the usual trouble shooting but still had the same problem.

I tried the same thing into the DI on the front of my Saffire and it still sounded horrible!

I compared it to some test clips I did with the acoustic guitar into the Eureka a few months back and it sounded totally different. It is the same guitar using the same settings etc but now it sounds bad!??

Could either be the guitar (which is very cheap) or something else!?

Any ideas?

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www.richardpenrose.com