High pitched noise when connected via USB

OWL
#1

Hello! Just got my OWL today and it’s even better than I expected. It feels so heavy and sturdy! Love it!

There’s one minor problem though. Right now I don’t have any 9v power supply so I decided to just plug it via USB to my PC, and then plugged the guitar into the input, and then connected the OWL to my Zoom H4 audio interface. This produces a very audible high pitched noise which I assume is from the USB. Should I rather get a proper power supply or is there some other way to get rid of this noise?

(I’m on Ubuntu 13.10, on a brand new custom built computer, I tried all USB sockets, USB3 and 2, with the same results)

#2

Hi Johannes,

Thanks for the kind words!
Some computer USB ports tend to be very noisy indeed… Can you try with another power supply, or a USB phone charger ?
We will add some links to recommend specific models soon.

cheers
Giom

#3

Confirmed, just tried plugging it into another computer lying around here (2008 macbook pro) and no audible noise at all. :smiley:

Any specific voltage or other specs I need to keep in mind if I use phone chargers?

Also, given the fact that the linux box with the noise is my main work computer I was wondering if there is any way to avoid that noise? external USB hub?

#4

That is a good idea, trying a powered usb hub.
If we can provide the community with a bunch of hubs that work fine, it would be great!
The first one who finds a good one please posts !

#5

Should we maybe add this future list to the wiki? Similar to how the community around Raspberry Pi is doing ( http://elinux.org/RPi_VerifiedPeripherals ). Either a list with USB hubs that work flawlessly, or a list of USB hubs that should be avoided.

#6

Great idea, we’ve had a couple of reports of noisy psu’s to avoid.
Also worth noting that when plugged in to a laptop, any noise is likely to stop if you unplug the laptop power adapter.

On the whole, an external 9v psu will generally give better performance than USB power, even the cheap, switching ones. Just watch out for low (<30kHz) switching frequencies!