Any real problems with the QC power supply?

I’ve been considering purchasing a back-up power supply for my Quad Cortex as PS failures are not uncommon for any device. I’m trying to decide between purchasing an OEM supply or purchasing an aftermarket supply.

I see a lot of people ranting about the wall wart that comes with the QC. I agree that “it ain’t much to look at” and the cord is pretty wimpy. That said, I haven’t seen many posts of actual failures or other problems related to the OEM supply.

Because of it’s size and weight, I assume this is a switching (no transformer) power supply and the cord is thin and pretty stiff. For the purpose of mounting it in a pedalboard, I see these features as an advantage. Keeping this part as compact and light as possible is a plus. As long as it supplies the required amount of current at the right voltage and without introducing excessive ripple, what more do you need? As for complaints about it not being grounded, If the QC doesn’t require grounding through the power supply (it doesn’t), why would you want to have another possible source for a ground loop?

Has anyone here had an actual problem with their original power supply? If so, please weigh in.

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People claim that the included power supply is “noisy” in some way. I personally haven’t experienced this at all. I use the stock supply at home. I have an aftermarket one that has a brick in the middle of the cord and uses an IEC cord to plug in, mostly just to avoid having a wart on a power strip at a rehearsal space or at a gig.

They’re both equal in terms of noise floor and whatever. I don’t see the advantage of buying a $200 cioks supply or however much they cost.

I’m gonna get a lot of heat from people on this forum for this opinion. But it’s been my experience.


Thanks for sharing your experience, TJB. I haven’t found the QC to be noisy either. Maybe it’s mostly folks running two compressors and three O-drives into a dimed Dual-Rec model that are experiencing noise issues. :man_shrugging::wink:

if you’re looking for a 3rd party option, I highly recommend the Sweet Foot Power supplies. You can get one that just powers the QC or one what will also power some pedals or whatever you need. Mine has been rock solid for me.

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Since this topic is eventually gonna get into “What power supply do you use?” territory, here’s a link to a previous discussion, there are already quite a few:

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i haven´t had or seen issues either with it breaking but i´ve seen a couple of posts of how people have had the QC disconnected because the cord is so thin and it´s very easy to disconnect unlike other units or equipment.
I think if it´s for home use or a well isolated spot on a stage it shouldn´t cause trouble

The OEM power supply is very noisy if you only use the QC with a guitar and headphones. Try it and see. This is fine when connecting the QC to another unit via USB or cable to a powered speaker etc. This is because the QC is not earthed. It needs connection to a separate unit that is earthed.

Neural say they are working on an updated power supply but this has been in the works for at least a year or more.

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Not everyone appears to have issues, mine has been rock solid/quiet since day one but I am definitely aware that there are other owners impacted by some noise issues which I hope gets resolution.

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I bought the power supply that you had suggested and used that one at church and left the original one at home. Recently I started building a pedalboard for my QC with some additional pedals so I went ahead and bit the bullet and got the CIOKS DC7 and the Crux. I feel really good about having it although it was almost 300.00. Now I can supply just about anything I would like to add. I never had the noise issues either.

Are you saying if you use with only headphones and a guitar you have no noise issues? If I touch the case the buzzing stops due to me earthing the QC. I was told by Neural support it is the way the QC is designed to be connected to other devices and that to me implies every unit is the same? I am struggling to see how mine could be earthed differently to yours? If so it sounds like I should be advised to return the unit to be replaced or repaired to be wired like your unit?


Grounding noise is really a moving target as it’s totally dependent on the other equipment that a device is connected to, along with the line power (from the building outlet(s). Running all of the connected equipment off of one building circuit, and better yet, through a quality power conditioner, can really help. Inductive noise from lighting and building wiring adds yet another element to the list of possible noise sources. Usually, noise from a bad power supply shows up as hum from poor filtering. If the voltage from the supply is low or amperage capability is limited, it can drive up the noise floor by starving the device of power. Usually in these cases, with a digital device, there would also be issues with errors like freezing and/or shutting down. Sorry, got a little in the weeds here. Obviously, having a quality aftermarket PS that can supply 12v to the QC and 9v for your other pedals/devices has it’s advantages.

Since few people are complaining about any of these issues, I’ll assume that the OEM wall wart tends to be pretty dependable. I guess I’ll look into a second one as a backup.

Thanks for weighing in, everyone.

That is correct, I have had zero issues related to noise from the OEM power supply. Early on when reports of ground related noises surfaced, I tested multiple scenarios and was glad to discover I had no issues. The only issue I ever had noise related was when setting up using 4CM, I had a ground loop and resolved it with a recommended Ebtech Hum Eliminator. About a year ago, I picked up a GlobTek PS from Digi-Key (also highly recommended) to have a secondary PS which it a bit more robust and uses IEC power. No issues with that supply either etc.

I assume all QC’s/power supplies are wired/built the same but where and how they are being used is probably a large factor as well. For me, all my instruments are well shielded and everything runs through a Furman Power Conditioner. I use all premium quality Mogami cables and have my studio setup where LED lighting and other interference is minimal.

Regardless, I would definitely reach out to NDSP via email at so they can log your issue and help provide resolution.

If you don’t want to wait for NDSP, you may have already seen the previous posts but the Globtek PS Digi-Key part number: 1939-1233-ND works nicely for around $24 shipped in the US. Much more robust and solved the grounding artifacts that some have experienced, note I didn’t have the noise issues but wanted a spare PS just in case.

If you get it, it comes with three tips, use the larger yellow tip etc., also before you push the tip in, ensure the polarity is correct for QC (center negative).

Never had any problem from day1, sometimes a ground loop, turning the ground lift on or off always works.

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I have the same experience when using headphones. I have my QC connected to Spark amp just to get rid of the hum, but that works.

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No, I find a little noise through my headphones with high gain settings and a noise gate when I’m not careful but overall I think it’s perfectly fine. When I connect to any outboard gear the noise goes away. It was worse when I first purchased the QC, I don’t know if they were able to tame it a little through updates or if I just got better at tweaking my setting :man_shrugging:. Plugged in via usb for recording, good. Guitar input, 4CM, effects return through tube amp, good. As a solo gig rig to foh, good. Grounded or ungrounded monitors for practice, good.

One note, I make a unique preset for every situation. So, I make my headphone preset, copy and paste that and tweak it for monitors/foh with its own tweaks to sound nice, then do the same for my amp effects return.

I did a test on this the other day. There was no difference using headphones when I was plugged into anything else or if the only connections I had were the guitar, power, and headphone jack. No change with how “noisy” things were, even with all gates turned off. Noise was from my guitar pickup settings, not the QC. Single coils ya know.

Thanks for sharing guys. It must be my unit then. I’m going to make a quick YouTube video to see if anyone else has the same issue. Easier to show how bad it is in a video rather than some writing in the forum I suppose.


I have uploaded a video to YouTube to demonstrate the buzzing I get using factory presets. I can use a noise gate but the buzzing is so much it’s needs extreme settings which kills any sustain. It is fixed by plugging into another earthed device but is very annoying to have to do this. Axe Fx II didn’t have this issue and some people on here seem to be fine. Already contacted Neural support and they just said wait on an updated power supply. That was over a year ago :frowning:

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That’s terrible, Alan! By the sound of it, I would guess a problem with guitar wiring or guitar cable but that wouldn’t explain why it goes away when connected to the amp. Have you tried lifting the ground on the output feeding the amp to see if the noise comes back? If so, it would point to an internal grounding issue in the QC. How frustrating!


Yeah, that’s totally not how it should be. People reporting buzzing I thought they were just picky about the amps or something but that’s just nasty. I don’t have this at all with my unit. I get an inconsistent crackle, but that doesn’t matter if I’ve plugged into another device or not.