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Raspberry Pi USB : noisy?

somebodyelse

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First guess with buzz/hum is always grounding. How are the Pi and the external hard drive powered, and are they grounded?
 

somebodyelse

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Yes, if you mean they are two prong?
Yes - I edited to clarify, but you beat me to it. Since it's got a psu I assume the Seagate is one of the bigger drives that can't be powered just from the USB, and has a 12V power supply. Do you have an alternative storage device that can be powered from the USB cable, and/or a battery USB power pack you could power the Pi with for testing?
 

Oranges

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I will try that this evening. I guess I always assumed it was better to not burden the pi with powering the hard drive so I used the big one with its own cord
 

abdo123

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I will try that this evening. I guess I always assumed it was better to not burden the pi with powering the hard drive so I used the big one with its own cord

you can even power the pi off a laptop and have that laptop run off its battery. Not ideal ofcourse but to test for ground loops it should be okay.
 

Oranges

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I have a USB powered drive I can try first. Ironically, using it currently on a pi3 setup in another part of the house. It's going into a hub for the same (possibly unnecessary) reason, to avoid the pi having to power it
 

Oranges

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I think this helped some, but now I have buzzing with the pro-ject tube box pre amp. I can have everything else plugged in but that and it's fine.
 

somebodyelse

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Ah - the wonderful game of chase the ground problem! Jensen Transformers have some application notes that might help you. AN006 presents a systematic method for solving ground issues, while AN007 has a more detailed version and a huge amount of technical detail about the underlying problem. You may come to appreciate why the pro audio world uses balanced interconnects, even if that's not really a solution given where you are now.

Check the Pi docs to see the current limits for each model, both for individual ports and combined. Since the DAC isn't bus powered I expect you'll be fine with a bus powered HDD unless you've got an unusually weak psu for the Pi - IIRC that's covered on the same page of the docs. I'd also look at mounting storage as a network share rather than a local drive.
 

Oranges

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Oddly though, even with no hard drive or the USB powered drive, and an ifi ipower powering the pi, I have no buzz unless the pre amp is hooked up now.
 

audio2design

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Oddly though, even with no hard drive or the USB powered drive, and an ifi ipower powering the pi, I have no buzz unless the pre amp is hooked up now.

High peaks currents from the drive, getting through AC filters and back around through the pre-amps .... probably
 

Oranges

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If I take the dac, pi, hard drive completely out I still have buzz from the tube pre amp ..
 

terrys999

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If I take the dac, pi, hard drive completely out I still have buzz from the tube pre amp ..

I had similar problem.
I found the problem was from an electric blanket.
Also a small light under the cooker.
Turned em off noise vanished.

Check what’s turned on,
 

AnalogSteph

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The Nait 5si appears to be an IEC Class I device, going by its 3-pin IEC power connector. Presumably the not-very-clean mains leakage currents of the larger switch-mode wall warts found in the setup (Seagate, Tube Box) are making their way to ground via your unbalanced audio connections.

You may be able to help matters by using RCA cables with the lowest possible shield resistance. Running heavy-duty ground connections between devices (e.g. using speaker wire) alongside the signal cables is another old trick.

That should get things sorted as long as the problem isn't inside the Naim (well, in fact the separate ground trick would still help). I found a picture of its insides and must say I'm not at all impressed for the price. Not only is the combination of Class I construction and unbalanced connections asking for trouble, the secondary-side transformer wiring is tied but not twisted. That I imagine would elicit a frown from Mr. Douglas Self. The amateur hour factor is a bit too high for my liking at 1399€, which is not exactly chump change.
 

Oranges

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Would this still be the case if I have the wall wart for the pi, hard drive, and pre amp all on a different strip from the Naim? Because I tried that and it was the same. I'm wondering if it's just the power cable of the pre amp? I'm going to try a EBtech Hum x on it first this weekend
 

G-rig

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Hi guys, just put together a Rpi4 with usb to my DAC (DACMagic)
All works well with Volumio and Tidal.

getting some feedback through my monitors (XLR cables), seems to be due to the cheapo USB cable.
Was wondering if these audiophile cables ones will fix that issue or is it better to and add a HAT with Coax out Would have to mod the case?

Thanks
 

JSmith

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audiophile cables

Now, occasionally you may run into a ground loop with a USB DAC where you often hear the activity in your computer. In these cases, I suggest using a Toslink Optical input



JSmith
 

G-rig

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JSmith
Sigh..
Not talking about Audible sound differences, read the post. It's got to do with interference and ground loops or something
 

wwenze

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Hi guys, just put together a Rpi4 with usb to my DAC (DACMagic)
All works well with Volumio and Tidal.

getting some feedback through my monitors (XLR cables), seems to be due to the cheapo USB cable.
Was wondering if these audiophile cables ones will fix that issue or is it better to and add a HAT with Coax out Would have to mod the case?

Thanks

Hold on, feedback?

As in the one that gets really loud? Or the one where somebody put his mic too close to the speaker during Zoom calls?
 
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