Bottlehead Forum
Bottlehead Kits => S.E.X. Kit => Topic started by: denti alligator on February 08, 2017, 04:14:23 PM
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I'm using my amp exclusively for headphones and I notice some nasty interference when playing files from my PC. It's a high pitched wheezing that goes in and out. It's pretty quiet, but noticeable in between tracks and with quiet music.
I thought it might be the wifi, but have ruled that out. It's only when the CPU is going. So when I start a track it starts up; when I stop a track it stops. When I open a browser on the PC, it starts up, etc.
I've put copper tape shielding on the inside of the PC case and the SEX amp. And I've tried moving the amp further away (it's now about 6 feet away). No improvement.
Any thoughts on a next step? Some more robust EMI shielding for the PC?
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Hi denti-alligator,
When you say "only when the CPU is running," do you mean when the PC is running, or the processor itself? Are you running the files from a CD in the PC drive, from the hard drive of the PC, or from memory or a SSD?
TIA,
david
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This is just the noise of your PC doing its work. It will go away if you add a DAC and cable the two together with Toslink.
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I should have specified:
I am running the PC to an external DAC using USB.
I mean that the noise occurs when the CPU is higher that simply its idle mode. The tracks are on a NAS, being transmitted over wifi. But I tested with a track on the PC and it was the same.
I'm using the Stereomour as a source selector, by the way. I just tested the Stereomour on its own. Putting my ear up to the speakers and turning the volume all the way up I can hear the same sound. Not really audible at normal volume and listening distance.
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It's definitely the PC. My toptop doesn't produce the same sound. I've ordered a USB filter. Hopefully this will help. I'll report back.
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order a toslink cable (and USB to toslink adapter if you don't have an available toslink port).
-PB
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order a toslink cable (and USB to toslink adapter if you don't have an available toslink port).
-PB
I can't do DSD over toslink, unfortunately. My DAC sounds pretty sweet with DSD, so that's what I'm aiming for.
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For the record, this is (or at least, can be) a thing. It's an intermittent scratchy/whining sound much like coil whine from some laptops, or how early 3G phones could sometimes interact with wireless PA systems or speakerphones.
In my case, it's definitely not correlated with the attached computer's activity. Only present at a low level so I dealt with it for a while.
In the end I did track it down to other wireless devices - specifically, bluetooth and Wi-Fi. This first showed up in my 2.1 model when I replaced a B/G router with a N-capable one. My amp is on my desk, the router is almost directly under it on a shelf. Verified further by doing some heavy wireless streaming next door. However, finally figuring out the source let me reduce it greatly by moving/reorienting the router.
Your mileage may vary, but that's my experience.
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It's definitely coming from the computer. And it's not the wifi.
I got an ifi iPurifier for the USB. Doesn't help! So I'm sending that back. I've ordered a more robust USB cable, which I'll try next. After that I have no clue what to do.
When I play from my laptop I don't get the interference, but my laptop doesn't have the power to do DSD, and anyway, it's my laptop. I need it for other stuff.
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I'm returning the motherboard. Hopefully that will solve this.
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After trying a ton of other things, including switching out the motherboard and power supply, etc. etc, I finally solved this by putting the 3-prong plug of the S.E.X. into a 2-prong plug. Is this safe? Should I attach the ground somewhere.
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After trying a ton of other things, including switching out the motherboard and power supply, etc. etc, I finally solved this by putting the 3-prong plug of the S.E.X. into a 2-prong plug. Is this safe? Should I attach the ground somewhere.
https://en.wikipedia.org/wiki/Cheater_plug#Safety (https://en.wikipedia.org/wiki/Cheater_plug#Safety)
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My first SET amp was (is, I still have it) a Triode Corp TRV A 300 SE. It actually came with an adapter that allowed disconnection of the ground. I put it in a ziplock with a note that says " never use this!" It is a great little amp. It's the amp that changed my audio life.
Jamie
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https://en.wikipedia.org/wiki/Cheater_plug#Safety (https://en.wikipedia.org/wiki/Cheater_plug#Safety)
So what are my options for removing the ground loop?
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Sam, is the computer on the same circuit as the rest of your system, including the SEX? I have some components that make all kinds of noise if they are not all powered by the same circuit ( on
the same circuit with respect to the home's wiring, you know, on the same breaker).
Jamie
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Yes, they are. All plugged into the same power strip. I've got a new strip on the way and will use a GFCI tester tonight to make sure there isn't something wrong with it. But besides that I don't know what to do.
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Have you tried a different circuit within the house? You might have a ground connection on that circuit but it could be weak depending on how the house is grounded?
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I will try that now. This only happens with one particular PC that I use for music. But lifting the ground on that PC doesn't make a difference. Only the ground on the SEX amp does. Could there be an issue with the wiring of the SEX? How could I determine that?
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Just tried a different breaker. Same noise.
Same noise is audible through Stereomour and speakers, too, just much quieter.
Since this isn't a problem restricted to the SEX I'm going to start a different thread in the general forum.
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So what are my options for removing the ground loop?
http://bfy.tw/BMLX (http://bfy.tw/BMLX)
I'm just mirroring what PJ posted in the other thread you started on this same topic.