Seriously - the hiss!

i mind as much about having to wait for it to boot first in places with funky power as I do having to turn the noise gate up another 10% than i might with my rack unit if i were using it instead of the noise gate block

FWIW the hum boot first is never going to go away, it has to do with the way its designed, its boot up scan of the outputs, and the power method of the hardware.

It was not a boot-up hum in my case.
It was a permanent ground loop after the device was completely booted. I was aware of the problem with the boot-hum. That’s why I let the part boot up without XLR cable (several times). Didn’t help.
I had the whole time ground-hum. and as I said: no other modeller at this festival had the problem, I myself then played Helix, without any issues.

I love the QC because of sound and form-factor, but it’s unreliable and my trust in NDSP has completely hit rock bottom in the last year.

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im interested in what was up with that, too bad we will probably never know

I’d like to know that, too. I sent the device to NDSP for testing afterwards. It was there for almost 2 months without anything coming out. When I asked if I could have my device back after all that time, they sent me an exchange device. Since then, I no longer have any confidence in the QC.

something something dont plug in the outputs until its finished booting something something

I’m pretty sure this isn’t actually necessary. The XLR grounds are optical, for quieter switching, but they default open when powered off. This means you might hear hum from powered monitors when connected to a QC that’s off.

It doesn’t mean cables need to be unplugged while it’s booting.

So just for clarity, I don’t have anything plugged in via XLR and I have no problems with hum.

@DeadCircus If you read my original post, I noted two issues.

One was hum - and how ridiculous of a solution it is to have to plug into another grounded device to eliminate it. Not boot up hum. Not popping. Constant hum. The “it was designed that way for a reason” is just not true. So in my original post I asked NDSP to provide a new feature. Which is a grounded power supply.

The second is hiss. I’ve tried two QC’s. Both have a constant hiss even with lower gain. It is a very common problem among QC users. So in my original post, I asked for another new feature. A firmware upgrade with models that don’t hiss at low gain.

That’s all. I love the QC. I do feel like I got ripped off a bit though.

@kemparinho I have an Axe-FX III and Kemper. I think that’s why it’s so frustrating to me. Neither of those have this issues.

i have hum when connected to my computer-plugged reference monitors and also at the bad power in one of my jam spots. when i boot the QC without the outputs plugged in the QC does some kind of resistance checks or some shit on bootup and it analyzes it based on whats plugged into the outputs. with bad power this will cause hum. if you boot it up unplugged from the outputs this doesnt happen until you switch off the QC if its still plugged in, and it will stop once you disconnect the power supply.

im not the only person who has had this issue, and I learned how to get around it by doing the unplugged thing whenever i boot up in either of those locations. I learned this from a post on this forum somewhere.

my understanding is if they had a more “regular” or expected type of power system this wouldnt ever happen. the grounded power supply thing would fix that i guess, but its not that hard to just boot it up without the xlr’s plugged in

shorter explanation: plug in XLR before boot and it hums if bad power scenario, boot without plugged in and its quiet, but it will hum when you turn it off.

Yes, my first device did not have this problem at home either. However, the replacement device did.
A buddy of mine also has a QC and was with me a few weeks ago with it. We connected his QC to the same outlet with the same equipment connected. Mine had Hum, his did not.
I then asked NDSP if different hardware was being used here within the device.
The answer to this: a very clear NO. All QCs are identical in terms of hardware.
Okay, hardware is the same, software is the same and the problems are different?
Furthermore: What about the development update from June 2022 in which NDSP even wrote that different hardware has to be used due to supply shortages?
I asked this last week and am still waiting for an answer.

This would now be the third time that I was lied to by support (all verifiable by mail history).
I have had various modelers and never any problems with the device or the support (apart from a broken footswitch at the Helix, which was replaced within 1 week). Alone the time I have already wasted here with mail traffic… As I said above, my trust in NDSP has hit rock bottom. There is unprofessionalism, intransparency and ignorance here with regard to the development of a reasonable and reliable device.
But what must also be said: My buddy uses the QC every week for gigs (with the original PSU) and has NEVER had any problems with noise. Yes, of course he also has the WiFi problem, which is simply a fail design. But other than that, it has no problems at all. So there must be differences here.


This concerns me but it make sense cause i didn’t understand that people who uses other modelers didn’t see a difference, the noise differences with my Kemper is so obvious…

I have had mine for about a year. Spent a few weeks cutting over from my old setup and haven’t looked back. I pretty much only play gigs or rehearse for gigs with mine so I am really perplexed at the issues being described. One night I did have an extreme noise issue but it only happened with a passive guitar. An active guitar (with a battery) was fine. It was weird. Between sets I finally traced it to a bad cable. I don’t know the science behind that but it’s not a problem anymore after swapping a cable out. Otherwise, and as well, I was already using a pedal board with a powered IO buffer. I kept a couple outboard delays, from my old rig, etc, so I mounted my QC and rerouted as necessary. My QC out plugs into the IO buffer and then that runs to my cabinet. Maybe my setup using a buffer had already “solved” it for me, but I don’t have any noise. Unless I want noise. And I always use a gate block at the front of the chain no matter what. That’s just an old school hold over “this is how I do it” from having a rack mount comp/gate in my old rig…works for me. I wish I could color code my scenes in gig view mode. And I wish the midi control for changing to gig view wasn’t a toggle - it needs two values - one for on and one for off. Otherwise the QC has not disappointed me.

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I feel they need to revisit the gain staging at the front end of the QC. Much more hiss than my Helix. I sent them a controlled video example. And obviously much more than real amps which I have tested it against. I reduce the hiss by putting the input gain to +9.3 and have my first block in the QC as a gain block set to -9.3. You’ll notice there is a gain staging adjustment they make at +9.3 (or might be 9.2) on the front end. This gets me back to unity gain and reduces hiss greatly. I play vintage style starts and LP with vintage output pickups. Mostly classic rock. Lonestar, AC30 or Plexi with a few drive pedals in front. This won’t work with hotter pups, and maybe it’s not an issue for those players. I’m playing this rig constantly live and its awesome. I think this is something more mature units have already worked out i.e. Helix, Fractal, Kemper. I think this unit is awesome for us old school players, but it is very hissy. And I refuse to use noise gates!!!

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Thanks @Bigrockandy ! I will try the gain block setting. I just hope NDSP can solve this with a firmware update. I don’t like using noise gates either. Unless I’m playing high gain. But like you, mostly classic rock stuff. If I didn’t also own a Kemper and Fractal, I’d probably accept the noise. :smile: . But when I fire one of those up and they are dead quiet without a noise gate (same amp models and settings), it’s frustrating.

Here QC grounded, no hiss, very quiet


Zero hiss from my unit and I’ve owned it about a year now and done about 80 gigs. Also use high gain captures which would amplify any low noise hiss.


Same, pushing 20 gigs of all sizes, plus rehearsals and sessions at home. Never noticed hissing and I use everything from clean to hi gain too.


Just out of curiosity and to maybe understand the root cause a bit better.
Do the ones who experience hiss use FRFRs or power amp + guitar cab?
I use a power amp + cab after the QC and I have no noise problems, no matter where I play.
Should normally not make a difference, I know. But I can’t imagine why some seem to have the problem all the time and others never.


I’m using stereo FRFRs and am noise-free.


Interesting. At +9.3db, I assume you’re pegging the input meter but, by trimming the gain in the preset, you have no distortion? I don’t understand why the A/D converter isn’t clipping…interesting. I haven’t experienced an inordinate amount of hiss from my QC but I might experiment with this myself.