Would getting a non-bus-powered audio interface solve my audio interface problems?

I have two computers, a desktop and a laptop, and I have two audio interfaces, a Scarlett 2i2 and a very old and cheap Edirol UA-1EX which I'm using to help diagnose the problems I have been having with the 2i2.

I also have two problems, and I'm not sure if they are related or not.

The first is that when I enable phantom power on the 2i2 I get noise in the inputs over and above the faint white noise which is normally there even when phantom power is not enabled. The noise, which is hissy, not pitched, is uneven and sounds bass-heavy; it seems to rumble. I get this with both computers, but it is very much worse when the 2i2 is connected to the desktop than the laptop. On the desktop, it pushes the input level meters quite high. On the laptop, it never shows on the meters as any more than an occasional flicker at the bottom when the input gain is set to a level appropriate for recording.

The other problem I have only occurs on the desktop, not the laptop, and I get it with both my audio interfaces. Whenever a device that has its own connection to the mains, such as my bass amp or my digital piano, is connected to one of the inputs, I get a very obtrusive buzzing and squeaking at that input. It is not a low-frequency mains hum. The sound is irregular and seems to correspond to the activity of the computer. Even if I put a DI box between the audio interface and the external device, I still get these sounds.

Would replacing the 2i2 with an interface that doesn't depend on the USB bus for power, such as an 8i6, solve either of these problems?

I have tried to find other solutions to the problem of the unwanted digital sounds from the desktop computer, but I have got stuck because I'm just not sure where the problem is. If it is with the power supply, then that can be replaced at a reasonable cost, but if it is the motherboard, I would have to replace that, along with the CPU, memory, heatsink and Windows license, which would cost a huge amount.

If I can at least solve the problem with the phantom power, even without resolving the problem of the digital noises in the desktop computer when connected to external devices, then I will be able to do my sound recording on the laptop and move the project later to the desktop for post-production, which wouldn't be an ideal workflow, but it would at least enable me to get my work done.

So would getting a non-bus-powered audio interface help me?
 
Hi,
The first issue, about phantom power, could easily be coming from a faulty cable or microphone. Do you have other cables/microphones to rule that out?

The second issue...Do you still have the issue if you power both the computer and the amplifier/piano from the same power outlet?

What country are you in/type of mains power do you have?
Smarter people than me will want to know.
 
Whenever a device that has its own connection to the mains, such as my bass amp or my digital piano,

What does this mean? To the Mains? And what are you plugging into on the bass amp and piano?

The first is that when I enable phantom power on the 2i2 I get noise in the inputs over and above the faint white noise which is normally there even when phantom power is not enabled. The noise, which is hissy, not pitched, is uneven and sounds bass-heavy; it seems to rumble. I get this with both computers, but it is very much worse when the 2i2 is connected to the desktop than the laptop. On the desktop, it pushes the input level meters quite high. On the laptop, it never shows on the meters as any more than an occasional flicker at the bottom when the input gain is set to a level appropriate for recording.

What kind of mic are you using? What happens when you turn the gain all the way down?
 
I have tried two different mic cables, with the same result. The mic I am trying to use is a Rode M3. It has an on-off switch, but even with this set to off, I get the noise when phantom power is switched on. If I turn the gain down to zero, the level of the noise diminishes, but not completely. I still see flickering at the bottom of the level meter on the DAW. (I'm talking here about what happens on the desktop computer.)

The only other mic I have to test with is a very cheap dynamic mic, so I don't know if that can tell us anything about how phantom power is working. For what it's worth, when this mic is plugged in and the gain is set to high, I see a tiny bit of flickering at the bottom of the input level meter in the DAW, but I think this is just ambient sound.

I also think I may have made a mistake when I said that there was some phantom power-related noise on the input to which the mic was connected when the 2i2 was plugged into the laptop. I must have forgotten to turn the mic off and mistaken ambient noise for the noise arising within the audio interface. I can't detect any noise now. I used to have a bad problem with this kind of noise on a laptop, but perhaps it was on my previous laptop, not the one I use now. I used to get the noise even on an input with a guitar plugged in (passive pickups). I'd really hear it when I ran the signal through one of the Rammfire presets in Guitar Rig.

So it seems that the noises connected to phantom power are specific to particular computers.

What I meant by devices having their own connection to the mains are ones that don't rely on battery power. I plugged a Casio VL-1, running on batteries, into the 2i2 and I didn't get the computer noises. That only happens when the device plugs directly into the mains (like my bass amp through its IEC socket) or has an external power supply that plugs directly into the wall (like my piano). I have tried running such external devices from the same wall socket as the desktop computer and from a different wall socket, but it makes no difference.

I live in Belgium and have 230V 50Hz electric supply.
 
Something powered by mains electric. household-electricity?

Ah, gotcha. different terminology on this side. Whenever I hear 'mains' in an audio reference, I think Main Outs on a mixer or Main PA speakers.

With that in mind, going back to the OPs question on the buzz, it sure sounds like a ground loop. To fix that, re-wire the house (seriously!!) but short of that, ensure you have all your connected audio equipment coming out one electrical outlet... or, if I may, one main. This ensures all the grounds are going back to the same one.

For whatever reason, when two outlets have separate ground wires going back to the same electrical distribution panel, there can sometimes be an electrical potential and that can cause a buzz. I actually have the same problem in my studio and for the life of me, I don't know why. I just plug everything into the same outlet and be done with it.

Not sure about the other problems you're having.
 
I have tried two different mic cables, with the same result. The mic I am trying to use is a Rode M3. It has an on-off switch, but even with this set to off, I get the noise when phantom power is switched on. If I turn the gain down to zero, the level of the noise diminishes, but not completely. I still see flickering at the bottom of the level meter on the DAW. (I'm talking here about what happens on the desktop computer.)

The only other mic I have to test with is a very cheap dynamic mic, so I don't know if that can tell us anything about how phantom power is working. For what it's worth, when this mic is plugged in and the gain is set to high, I see a tiny bit of flickering at the bottom of the input level meter in the DAW, but I think this is just ambient sound.

I also think I may have made a mistake when I said that there was some phantom power-related noise on the input to which the mic was connected when the 2i2 was plugged into the laptop. I must have forgotten to turn the mic off and mistaken ambient noise for the noise arising within the audio interface. I can't detect any noise now. I used to have a bad problem with this kind of noise on a laptop, but perhaps it was on my previous laptop, not the one I use now. I used to get the noise even on an input with a guitar plugged in (passive pickups). I'd really hear it when I ran the signal through one of the Rammfire presets in Guitar Rig.

So it seems that the noises connected to phantom power are specific to particular computers.

What I meant by devices having their own connection to the mains are ones that don't rely on battery power. I plugged a Casio VL-1, running on batteries, into the 2i2 and I didn't get the computer noises. That only happens when the device plugs directly into the mains (like my bass amp through its IEC socket) or has an external power supply that plugs directly into the wall (like my piano). I have tried running such external devices from the same wall socket as the desktop computer and from a different wall socket, but it makes no difference.

I live in Belgium and have 230V 50Hz electric supply.
Does the noise diminish when you are using the laptop on battery power? If it does significantly, then I'd wonder about noise in the mains (AC), and just revert to battery use or get a good line conditioner.
 
Ah, gotcha. different terminology on this side. Whenever I hear 'mains' in an audio reference, I think Main Outs on a mixer or Main PA speakers.

With that in mind, going back to the OPs question on the buzz, it sure sounds like a ground loop. To fix that, re-wire the house (seriously!!) but short of that, ensure you have all your connected audio equipment coming out one electrical outlet... or, if I may, one main. This ensures all the grounds are going back to the same one.

For whatever reason, when two outlets have separate ground wires going back to the same electrical distribution panel, there can sometimes be an electrical potential and that can cause a buzz. I actually have the same problem in my studio and for the life of me, I don't know why. I just plug everything into the same outlet and be done with it.

Not sure about the other problems you're having.

But as I said, I get the problem even when both the desktop computer and the other device are plugged into the same outlet. The bass amp's and the computer's plugs are next to each other on the same power bar, but the unwanted noise is loud and clear when I connect one to the other. I even once tried disconnecting the computer from the ground, but the noise didn't change.
 
Does the noise diminish when you are using the laptop on battery power? If it does significantly, then I'd wonder about noise in the mains (AC), and just revert to battery use or get a good line conditioner.

But I've never had the "computer noises" when either my current or my previous laptop has been connected to another device.

I've just discovered that what I do get when the bass amp is connected to my (current) laptop is a loud AC (50Hz) hum, but only when the bass amp is switched off. Once I switch the bass amp on I get near silence at the 2i2's input. This AC hum is what I've always understood a ground loop to sound like. However, the noises I get from the desktop computer are completely different. They are higher pitched and have an irregular, seemingly random rhythm, which is why I think they follow the computational activity of the computer.

Also, as I said in my second post, I now realise that I'm not getting the uneven hissy noise connected to phantom power in the laptop at all, or at least not at any level that is noticeable. And this is when the laptop is connected to the mains electricity. I was a bit confused about it when I made my OP, partly because I had remembered having this problem with my previous laptop. In other words, this problem with phantom power happens with some computers and not others, and in my present situation it happens on just one of my computers and not the other one, despite the fact that I am using the same mic, the same XLR cable and the same AC wall socket. I don't see how a ground loop on its own could explain that. Surely there has to be something the laptop is doing right that the desktop computer isn't doing right? Or have I misunderstood something?
 
But I've never had the "computer noises" when either my current or my previous laptop has been connected to another device.
..... Surely there has to be something the laptop is doing right that the desktop computer isn't doing right? Or have I misunderstood something?
Well there may be a couple or more problems here and you need to try to solve the ones that are relevant to what you really want to do.

I was suggesting trying battery operation with the laptop and 2i2 to see if the *source* of the noise was coming from the wall power. It’s possible some devices filter that better than others but it’s still relevant to understand where noise is coming from before trying to point fingers at which device is providing the path into the recorded signal. Sometimes the source of the noise is on the input side but sometimes it’s not. Doesn’t seem like that’s been determined.
 
The "computer noise" you are getting still sounds like a grounding issue with the wiring of your house. If I'm reading your posts correctly, you don't have any problems with the laptop unless you have the bass amp plugged into the 2i2 and turned off. Without the bass amp connected to the 2i2, you have no problems with the laptop. correct?

The problem occurs on your desktop with either the bass amp or a mic connected. What happens if nothing is connected? What about if you listen with headphones?

In the US, we can buy an outlet tester for about $3 which we can use to determine if the outlet is wired correctly. Are you able to buy something similar?

Another thing that can cause the computer noise is single pickups near your PC. Move your guitars away from your PC.

What kind of computer do you have?
 
There are many good troubleshooting rabbits-to-chase offered up in this thread. One more that I might add is: are you plugging in to a USB3 port or USB2.0? Not knowing how old your 2i2 is and you said your Edirol was old, I know I have experienced some of my older bus-powered gear does not play well with the newer 3.0 speeds.
Dale
 
Well there may be a couple or more problems here and you need to try to solve the ones that are relevant to what you really want to do.

I was suggesting trying battery operation with the laptop and 2i2 to see if the *source* of the noise was coming from the wall power. It’s possible some devices filter that better than others but it’s still relevant to understand where noise is coming from before trying to point fingers at which device is providing the path into the recorded signal. Sometimes the source of the noise is on the input side but sometimes it’s not. Doesn’t seem like that’s been determined.

But I'm not having a problem with the laptop at all. I know I said I was in the OP, but then I explained that I had made a mistake, in part because I had been thinking of how my previous, now defunct laptop had behaved. The problem is now entirely with the desktop computer. Though I presume that the fact that the laptop behaves fine when it is plugged into the wall suggests that the problem is not with the AC supply. Or is it more complicated than that?
 
Or is it more complicated than that?

Slightly more complicated and supports my idea that you might have a grounding issue with your house wiring.

Your laptop is not grounded. The power supply might have a ground pin on the plug going to the wall, but that ground does not go to the laptop. The laptop is DC powered so there is sort of this floating ground thing going on. Your PC is grounded. That would be the difference between the laptop and the PC and it makes me think there's a grounding issue going on. I'm guessing it is the wiring in your house because of the behavior with the bass amp.
 
My computer has an ASRock 980DE3/U3S3 motherboard, and a relatively inexpensive power supply made by Corsair.

I have also done some more careful listening to what I get at the input when the mic is plugged in on phantom power and I have realised that the ugly rumbling hissing noise I get on the desktop when the mic is turned off actually stops when I turn the mic on. In other words, I actually don't seem to have a problem with phantom power after all. I don't know why I didn't notice that before. And I probably wouldn't have noticed it if you lot hadn't been pushing me to double- and triple-check everything.

I also realised that I hadn't today actually tested the bass amp connected to the 2i2 when it was actually turned on. When I did this I discovered that I didn't get any unwanted noises. In other words, it is fine when connected in that way. This puzzled me because I didn't remember it working the last time I tested it, which was a few years ago. But eventually, I remembered that what I had been trying to do last time had been a bit different. I had tried to connect my bass both to my amp and to the computer using an active DI box. I tried this again just now and I got the "computer noises" through both the amp's speaker and through the 2i2's input. I tried the same thing with the 2i2 connected to the laptop and there were no "computer noises".

In other words, the 2i2 worked fine when connecting the grounded bass amp directly to the grounded desktop computer, but I get the "computer noises" when I try and do it through the DI box or when I connect an ungrounded device to the desktop, such as my piano or my drum pads.

Am I safe to assume that if I connect any properly grounded device to the desktop directly through the audio interface, it should work OK, just like the bass amp?

However, that still leaves a problem connecting things to the desktop that aren't grounded. Does it still look to you like an issue with the wiring of my building?

As for outlet testers, do you mean something like this? €13 seems to be the lowest price that I can find.
 
Honestly, I'm not sure anymore. There are a lot of variables and I'm having difficulty following them through all the posts. :confused: Maybe you can list out what is and isn't working.

The outlet tester you linked is what I'm talking about. It is a good investment if you ever plan to do gigs. There are a lot of venues out there with questionable electrical power. I carry one in my gig bag and test every outlet I plug into.

Glad to hear you got some of it worked out good. If I can help more I will. But maybe I'm running out of ideas.
 
Chilli, good sir whilst I am not familiar with the general state of the mains supply in Belgium, most of the 'richer' EU countries have a very safe and over-engineered system mainly because our 230V supply takes far fewer prisoners than 115V. That said, if OP's building is very old and not been rewired/checked for many years there could be a problem but in general we don't, audio gear noise issues are almost always due to the setup, ground loops and sometimes the lack of a ground because a collection of kit has been assembled which is all 'Class ll' i.e. earth free. Safe but noisy!

To OP: Does your mains power come in from underground or on overhead cables? The latter indicates an older installation and it might, I say just might be worth getting the system checked.

Otherwise, yes! I am banjaxed bay all the goings on and twists and turns! So...First job. Buy a 25ee digital test meter and then check ALL the mains cables and diss boards to ensure that they all have earth continuity. If they all check out aright check that every piece of kit that SHOULD have an earth to exposed metalwork DOES have earth continuity. Note: earth pin to chassis should read about an Ohm but will vary with contact pressure a bit and anyway the test leads have some resistance but anything much above 2-3 Ohms should be regarded as suspicious.

Assuming everything tests out ok, report back for ONE connection condition at a time! Say desktop to AI and bass amp.

And no, whether an AI is bus powered or not makes no difference to noise 'immunity'. That is in the gift of the particular AI designer. My NI KA6 for instance pulls just about max I from a USB port (~450mA) but has always been silent as the grave with at least six computers and laptops. In fact I have had about 5 AIs through my hands over say 12 years, some bus powered, some mains juiced. Never had a problem with any of them.

Dave.
 
So...First job. Buy a 25ee digital test meter and then check ALL the mains cables and diss boards to ensure that they all have earth continuity. If they all check out aright check that every piece of kit that SHOULD have an earth to exposed metalwork DOES have earth continuity..

Big +1 to that.
 
Thanks very much, everyone, for all the help and suggestions so far.

My socket tester finally arrived and, if it is working properly, it tells me that all the sockets in my apartment have live and neutral swapped with each other. Obviously there is a basic safety issue here, and the landlord, although he seemed to be having trouble understanding what I was trying to explain to him, has said that he will arrange for the electrician to come Tuesday morning. But in the meantime, I would like to get to the bottom of my audio problem as quickly as possible. Could this inversion of live and neutral account for my audio problems, or do I need to be looking for something else? One thing that occurs to me is that, since the socket tester can only display one error code at a time, perhaps there is a problem with the ground that won't come to light until the live and neutral thing is sorted out.
 
I've been looking at the socket tester in more detail and now I'm getting more confused. The socket tester looks like this: socket tester.jpg
After testing it in the (French-style) wall sockets, I tested it on a schuko extension lead, both ways round, and each way all three lights came on, which it says means "live neutral reverse", as opposed to "hot/neu rev". I don't understand the difference between these two. What I have read about Belgian wiring is that it may be that the supposed neutral may not necessarily be really neutral even though the design of sockets distinguishes between live and neutral in a way that it doesn't in neighbouring Germany and Luxembourg. Does this mean that I have no hope of getting rid of the ground loop?
 
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