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Little Dot MKIII picking up interference

post #1 of 14
11/10/09 at 11:45am
Thread Starter 
I got my Little Dot MKIII today, but i'm having trouble with it picking up interference from my computer. There is generally a static hum being emitted, but when I do things like open applications or maximise/minimise windows, it whines. It's the same whine as that is emitted by capacitors in my computer.

Why the hell is this happening. Plugging my iPod is fine, no interference, so it's something coming down the cable from my computer. Help!

My soundcard is an Asus Xonar D2.
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post #2 of 14
11/10/09 at 12:03pm
Quote:
Originally Posted by alex98uk View Post
I got my Little Dot MKIII today, but i'm having trouble with it picking up interference from my computer. There is generally a static hum being emitted, but when I do things like open applications or maximise/minimise windows, it whines. It's the same whine as that is emitted by capacitors in my computer.

Why the hell is this happening. Plugging my iPod is fine, no interference, so it's something coming down the cable from my computer. Help!

My soundcard is an Asus Xonar D2.
hi, please try to post MK III related topics on the MK III thread before creating a new one

In any case, from the MKIII manual:

Code:
Interference can be picked up by the tubes and cause odd noises. To minimize
interference, keep your Little Dot isolated from wireless routers, cell phones, telephone base stations,
and other common sources of RF or EMI noise. Generally speaking, the M8161 and other mil-spec
tubes will reject much more interference than the 5654/M8100s.
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post #3 of 14
11/10/09 at 12:13pm
Thread Starter 
Oops, sorry. Anyway, I have this thread, so I may as well use it.

I don't think it's the tubes picking interference up. I plug it into my iPod and it works fine, but when I hook it up to my PC, I get the bad interference. Unplugging the cable from the sound card immediately stops it, so it sounds as if it's coming through the wire.

Also, there is no way to tell what tubes I have as the ink has been rubbed off them. So I have to assume that the previous owner is correct in having it switched to EF95 mode.
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post #4 of 14
11/10/09 at 12:20pm
LOL I think this is what you're looking for-- although this will burn your wallet more

EDIT: I also have an MK III and I was thinking an iPod as my source but I'm worried about garbage in = garbage out, so I turned to FLAC from my computer but then my sound card is also crap so I've ordered a dedicated DAC myself

ANOTHER EDIT: the stock tubes is GE 5654, unless otherwise they've told you that they've changed it for out-of-stock reasons.
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post #5 of 14
11/10/09 at 12:30pm
Thread Starter 
Crap, so you're saying I need a DAC on top of what I have to get rid of the interference coming from my PC down the cable? That's a kick in the balls since it was stretch to afford the amp

Why the hell is my soundcard picking up interference in the first place? I have never had trouble when I just plug my headphones directly into my soundcard

EDIT: I just closed a game running in the background and the sound significantly decreased, but it is still there. It gets worse when something on my screen changes, like window size or background, so I guess it's coming from my graphics card.
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post #6 of 14
11/10/09 at 2:02pm
Ground issues in amp or you pc could be the cause. Since using the ipod is clear, the amp is ruled out. Heavy load on your pc increase the emi/rf? That could be the PSU.
Your pc needs more power, stressing the psu more.
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post #7 of 14
11/10/09 at 3:09pm
Thread Starter 
Quote:
Originally Posted by Stitch View Post
Ground issues in amp or you pc could be the cause. Since using the ipod is clear, the amp is ruled out. Heavy load on your pc increase the emi/rf? That could be the PSU.
Your pc needs more power, stressing the psu more.
The interference increases and decreases in direct correlation to the load on my graphics card. Capacitor whine from the graphics card can be heard both outside the case and through the amp.

I was told I either need a new graphics card which does processing outside the case or a DAC to prevent the analogue signal from being interfered with.
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post #8 of 14
11/10/09 at 3:40pm
I've got a HD4870x2 and i have zero noise when gaming.
Is there anyone that you can borrow a psu from? Its way cheaper than buying a dac or to replace your gfx card.
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post #9 of 14
11/10/09 at 4:04pm
Thread Starter 
Not really, no. But, i'm 99% sure it's interference with the graphics card. Some have capacitor whine, others not. So I guess you got lucky. I wonder if putting the default cooler back on would help?
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post #10 of 14
11/10/09 at 9:34pm
What's your gain set to? Higher gains will tend to magnify interference more.

You might also consider a good-quality well-shielded cable between the sound card and the amp. Not all cable shielding is equal, and a lot of cheap cables really skimp in that area.
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post #11 of 14
11/10/09 at 10:20pm
I know exactly what the problem is. This happened to me too and it was extremely annoying. I'll try to be as detailed as possible. So I have a MKIII as well and at my parents place in nor cal when my laptop was plugged in, the MKIII had the humming noise and once I took the power out, the noise was gone. Now here is the confusing part, in my college apartment in so cal, the humming was not there whether the laptop was plugged in or not. So, I diagnosed the problem to be the switching power supply of the laptop and ground loop issues in my nor cal home. What u can do now to get rid of the problem is try a ground loop isolator (i havent tried one personally) or get a DAC. I bought a DAC when I was in so cal and when I tried it at my nor cal home, the hum was gone. WHY: because the optical cable that connects the laptop to the DAC does not transmit interference
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post #12 of 14
11/11/09 at 9:23am
Thread Starter 
Quote:
Originally Posted by backtofront001 View Post
I know exactly what the problem is. This happened to me too and it was extremely annoying. I'll try to be as detailed as possible. So I have a MKIII as well and at my parents place in nor cal when my laptop was plugged in, the MKIII had the humming noise and once I took the power out, the noise was gone. Now here is the confusing part, in my college apartment in so cal, the humming was not there whether the laptop was plugged in or not. So, I diagnosed the problem to be the switching power supply of the laptop and ground loop issues in my nor cal home. What u can do now to get rid of the problem is try a ground loop isolator (i havent tried one personally) or get a DAC. I bought a DAC when I was in so cal and when I tried it at my nor cal home, the hum was gone. WHY: because the optical cable that connects the laptop to the DAC does not transmit interference
Thank you for the informative answer. I shall take this into consideration
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post #13 of 14
11/11/09 at 7:04pm
If you are so sure its the GFX card, swap it and stress it.
But the laptop story also points out the psu as source.
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post #14 of 14
2/9/12 at 7:22pm
Stitch:
Did u ever get this worked out? I had the same issue and resolved it by using a 3 to 2 prong cheater plug from Frys electronics for $1.50.
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