I wonder how many others might be experiencing something similar to this…?
I noticed recently, that there was a 7400Hz noise spike on my Minitaur. Also spotted it on my Blofeld, Supernova 2 and Kronos. It’s observable using a spectrum analyser in Ableton or Cubase. It is possible to hear it too, although it’s not ever-so prominent. Balanced cables on the SN2 made no difference.
Nords (Wave and G2) were all clear of the same noise.
It turns out that the Minitaur and Blofeld spikes disappear when the USB connection is pulled!
I’ve been talking to someone on a Facebook group, who bought a USB opto-isolator, which he reckons has cured his Blofeld issues.
…and I’ve not looked at the Elektron units yet for comparison.
So - anyone else seen similar? Any other solutions (other than masking with a noise gate)?
I’ve tried a few isolators which never seemed to make much difference and I’ve also tried taping one of the usb pins which is also a recommendation online none of which really worked.
The only exception was the OP-1 which reduced the noisy output really well.
As I moved more OTB I gave up trying to solve it and bought a MIO 10 and run all synths off DIN now which solves all the problems.
An audio ground loop isolator only helps if there is a ground loop introduced by audio cables or a combination of audio + other (ground carrying) cables.
But you can also have ground loop problems when only using usb cables (fixable by an USB ground loop isolator).
Noise can also be introduced into an analog circuit by insufficient shielding of a nearby digital signal path (Analog Rytm Mk1 and the restriction of concurrent audio streams over USB comes to my mind). There are also tons of eurorack users who have experienced noise problems generated by specific refresh rates of displays …
In general its not that straight forward to fix it. It’s more a trial and error thing to find the real reason and eliminate it.
I remember reading that Elektron boxes have the audio and the USB parts isolated from each other, possibly optically. I can’t remember where I read it though, so maybe I’m wrong.
What I do know for sure is that I’ve never had problems with Elektron gear, and plenty of trouble with Teenage Engineering gear.
I’ve had good luck with ferrite rings, even with USB. You can get a few dozen for a few bucks, so definitely worth trying. Also, you may notice noise when using USB, but sometimes it is from a power supply that isn’t shielded properly that gets exposed when using USB (again ferrite ring can help there). At least, that’s been my experience!
The Elektron devices I have looked into use a galvanic isolator chip on the USB device port, such as the Analog Devices ADuM3160, which is usually what external USB isolators use also (or the ADuM4160).
If it is a ground loop problem introduced by an usb cable in combination with audio cables it doesn’t matter in which path you break the loop. Of course you can break up this kind of ground loop by using audio isolators on the audio out cables.
You can test for this kind of loop by pulling out only the audio cables and listen to the sound via headphones plugged into the external device (but a spike at 7400Hz doesn’t sound like a ground loop problem … ground loop noise is in the 50-60Hz area).
Agree with posters above that even though you have determined the noise is from a USB connection, you can break the loop at the analog audio level. I purchased a few of these: https://www.amazon.com/Mpow-Ground-Isolator-Stereo-System/dp/B019393MV2 and put them in between the audio output from my devices to my mixer. This worked especially well for my TE devices.
Yes I did read your post. The noise is coming via the USB and leaking to the audio ground, which is why you hear it, hence my suggestion of an audio ground loop isolator, I have used these for exactly this kind of problem (but with Roland Boutiques, OP1 etc) and it solves the problem.
