CV noise?

foeny518
Posts: 2
Joined: Thu Jan 16, 2014 11:32 pm

CV noise?

Postby foeny518 » Thu Jan 16, 2014 11:49 pm

even with my modular turned off, if connect one of the CV out's from the quenexus to any of the CV in's on my modular - a faint, very high pitched tone comes through my monitors. no daw open, no gain on interface's input, no output volume on interface's outputs. still present when everything is powered on and running - but does not produce this sound if the qunexus is powered off (and connected via CV), or only connected by usb (no CV at all).

using official CV cable kit, double checked all cables to and from modular, interface and monitors. using a pittsburgh modular cell48 system 1 - brand new. also moved the quenexus to different usb ports, and directly to computer.

would love some advice, thanks in advance.
devilwidget
Posts: 16
Joined: Sat Dec 22, 2012 8:36 am

Re: CV noise?

Postby devilwidget » Fri Jan 17, 2014 5:56 am

there is an option in the editor to turn all of the lights off on the qunexus - that should get rid of the hum. The other way, if you need the lights, is to power by the usb expander (right side of qunexus rather than the left). This does mean buying the midi expander, but it gets rid of the hum (for me at least) and I use the expander as my main interface between my modular so I don't need to use a computer.
foeny518
Posts: 2
Joined: Thu Jan 16, 2014 11:32 pm

Re: CV noise?

Postby foeny518 » Fri Jan 17, 2014 12:47 pm

i figured it would lead me to midi expander, which i don't mind as i could easily employ its features.
i will try disabling the led feedback in the mean time - thx for response.
TheSupport@KMI
Posts: 726
Joined: Wed Jul 13, 2011 12:30 pm

Re: CV noise?

Postby TheSupport@KMI » Fri Jan 17, 2014 1:45 pm

Honestly, if you don't need to use the Expander functionality at all you can just plug a USB power supply directly into the Expander jack. It'll power up just fine.
2, 3, 5, 13, 89, 233, 1597, 28657, 514229, 433494437, 2971215073
keston
Posts: 1
Joined: Sun Jan 19, 2014 5:03 pm

Re: CV noise?

Postby keston » Sun Jan 19, 2014 5:38 pm

I am having the exactly same mysterious 2.5kHz whine as the OP. However, I want to have the QuNexus connected to the computer and my SCI Pro-One at the same time. Even if I power the QuNexus via the MIDI expander port I still get the whine when connecting it to the laptop. Also, the only setting I could find for the LEDs only turns off the keyboard feedback and not the rest of the buttons. Am I missing something? I found "LEDs Local/Remote" and unchecking caused no change in the whine. Thanks!

EDIT: I found the setting for all LEDs off and it fixed the problem. Thanks!
Danimal
Posts: 11
Joined: Sun Oct 13, 2013 3:26 am

Re: CV noise?

Postby Danimal » Mon Jan 20, 2014 1:04 am

ive simply killed the ground of my laptop. problem solved :) not the safest solution, but quick and dirty :twisted:
TheSupport@KMI
Posts: 726
Joined: Wed Jul 13, 2011 12:30 pm

Re: CV noise?

Postby TheSupport@KMI » Mon Jan 20, 2014 1:03 pm

For turning the LEDs off, there is an "LED Refresh Mode" option in the Hardware menu. It has three options: Normal, Control Only, and All Off. Normal means the LEDs behave normally — Control Only means the keyboard lights turn off but the utility buttons on the left side stay on — All Off means all LEDs are off.

And similar to Danimal's solution, if people don't want to be running computers without ground they can get a USB isolator, which is basically just a ground lift for a USB signal. Put it between the computer and QuNexus and the noise goes away.
2, 3, 5, 13, 89, 233, 1597, 28657, 514229, 433494437, 2971215073
an3
Posts: 48
Joined: Tue May 28, 2013 6:56 am

Re: CV noise?

Postby an3 » Thu Feb 06, 2014 9:19 am

well turning the leds of is no option, its kind of part of the controlelr issnt it. so KmC M. pelase come with a handabel solution, i cant use the midi to cv like this :(
mishik
Posts: 4
Joined: Thu Jan 16, 2014 1:15 am

Re: CV noise?

Postby mishik » Mon Mar 31, 2014 6:40 pm

Hi
Is it a bug or feature? :))
Are you planning to fix it?
neurocrash
Posts: 7
Joined: Sat Sep 22, 2018 2:59 pm

Re: CV noise?

Postby neurocrash » Tue Sep 25, 2018 8:15 pm

It's very disappointing to have to turn off the LED features.

I was sort of able eliminate the whine noise by using the TRRS splitter from the QuNexus CV kit (normally intended for the expression CV out jack) plugged into the CV input, but then the instrument audio output is disrupted unless it is going through the computer. If using headphones or direct to an amp, the audio is badly distorted. I'm guessing that means something is shorting inside the TRS CV out jack when cramming the TRRS splitter into it and that this could damage the QuNexus or the instrument.

The other thing I've noticed is that the whine only occurs when the QuNexus usb and instrument audio cables are attached to the computer. If I disconnect the QuNexus USB in and use the keyboard with the CV connections and USB out to KMI expander, the whine does not occur. If I disconnect the instrument's audio output from the computer's sound card and listen through headphones, the whine also does not occur.

This makes me think the problem is a ground loop between USB and instrument connected to the computer's audio input.

I wonder if there is any way to isolate the USB or the audio input to prevent this without degrading sound quality. A powered USB hub did not work.

Return to “QuNexus General Discussion”

Who is online

Users browsing this forum: No registered users and 1 guest

cron