Hi everyone, long time reader but this is my first post.
My setup is Quad Cortex running latest OS, Cioks DC7 power supply with Crux
I have been using my QC to practice with headphones as I’m not able to play loud in my house and my studio monitors are in storage. I can’t get rid of the ground hum and hiss when using them. in addition to this i noticed then when I turned my guitar volume knob down the noise became much louder. It’s got to the point where I am looking at other options, I never had this with my HX stomp or Kemper.
Things I have tried:
Changing out all cables
Factory reset QC
Plug an XLR cable into my interface (powered by USB) to listen on headphones there.
Toggling GND lift on input and output stage
Sent a report to Neural DSP
When i play a note there is a layer of fizziness on top of the note I just cannot get rig of.
I have emailed Neural DSP today but I am at my witts end. Any advice would be appreciated
You need to get the Ground from another piece of gear when using headphones; sounds like maybe you haven’t connected it to a grounded power source yet. Your USB-powered interface won’t ground it. Do you have a grounded computer connection available? A laptop or PC plugged into the wall? If so, try connecting the QC to it via USB cable, this works for some users.
Have you tried other power outlets in case you’re in an area w/ lots of EM interference?
I have tried other outlets in my house which hasn’t solved it. My macbook pro plugged into the wall in general has produced lots of noise when I have used the QC as an interface with the USB cable. I have already tried this unfortunately.
I tried taking one of the outputs and plugging it into my bass head using an instrument cable but this did not get rid of the noise either.
You could try it. Don’t turn the head on, but make sure it’s plugged in. The metal sleeve of the xlr needs to contact the metal chassis of the amp head
Connecting the QC to a plugged-in Macbook (Via USB) didn’t work for me, but connecting it via USB to a Windows Laptop, which in turn was plugged-in with a 3 prong power supply connector, did the trick for me. In case this helps.
Thank you CDTones. For context I live in the UK so all of our plugs are 3 pin.
Update
I took the QC off my pedalboard so the only things in the chain were QC (powered by cooks), headphones and the QC plugged into a plugged in MacBook via usb. The noise was still there unfortunately. It’s so frustrating.
I can’t plug into the DI of my bass head because I need a female to female XLR which I don’t have.
It’s honestly getting to the point where I might just sell
Good call on the UK side. Should’ve asked first. The only thing is reading around it looks like the Apple UK 3-pin plug adapter may not have a ground/earth connection on the UK side on the more recent models but can’t confirm (so there are 3 prongs, but Earth/ground may not be actually connected to the MacBook).
If this were to be the case, you’d basically see what I see from US side (where it is definitely not grounded as it is a 2-prong connector brick for the MacBook). Food for thought, and again, I had to use a 10-year old laptop with proper grounding after trying a lot of different equipment at home (Audio interface, MacBook, speakers, etc). The old Win laptop did the trick.
Makes sense. My wife uses a windows laptop for work so I will try that tomorrow. I really want to be able to use the QC!
Do you think the noise “on top of the note” I’m hearing is due to this issue? The notes seem to die very quickly particularly with the guitar volume turned halfway. Turning down the volume also makes the noise worse
Hard to say. It should help but man, this is one noisy unit IMO. For headphones I had to drop the multiout level to avoid clipping (instead of the headphone level)
This is disheartening as the QC I ordered will arrive in a couple of days and I had hoped to use the QC for late-night playing using headphones, without having to connect it to another device. I thought connecting it to my MacBook USB would work but, the power adaptor for the MacBook is not grounded (2-prong only) - would it work if I plugged into a power strip that was grounded? Although, that would leave me tethered to a wall outlet
Firstly I’m sorry to dishearten you. There are many factors at play here. I’m using mid 2010 MacBook pro with a crappy Amazon £20 power supply. My house is also extremely noisy electrically.
This was never really an issue for me before because I was using quad cortex in different ways but now my situation has changed and I have to play with headphones it’s annoying.
I will wait to see what neural say as I have contacted their support.
I would say to try it for sure and see how it behaves in your environment. When I need to move the QC for headphone use and dont have a way to ground it, I play around with the noise reduction block at the input, as well as the multiout level and can get it to be very useable. So again, try in your environment first!
I have been having the same problem with crackling, hiss etc with different headphones and connecting to R20 etc. In the end i took a mono jack and attached the ground/shield to the earth of a plug (being careful to isolate the other cable, check with multimeter and do at your own risk) and plugging the jack into the output jack. This stops the noise completely when the plug is plugged into a socket for me and it’s easier than plugging in switched off amps or similar
Just a question I guess… why are folks having noise issues with the QC I’ve only got mine about 3 weeks, and haven’t had any noise issues with headphones or 3/4 outputs haven’t used the xlr outputs yet… I’m in Ireland… Our sockets are earthed… I’ve only used it plugged into my audio interface 3/4 out to it… Should I expect issues when gigging this unit
I’m in Ireland too, if you’re plugged into anything earthed you’re grand, so FOH at venues etc no issues at all, I was having a terrible time with the ‘tic tic tic’ of a nearby electric fence … no cure for that but moving house!
Cool jonnix…nice to hear from another islander it’s like hens teeth on these forums… In my expo… . There is isolated extension leads you can purchase to keep power clean mite be worth having one, especially folks that are having problems…
Absolutely. If you’re plugged into something earthed you are fine. I only use this solution when practicing with headphones only or attached to non-earthed device (like the R20)
. There is isolated extension leads you can purchase to keep power clean mite be worth having one, especially folks that are having problems…