Prime 4 'grinding' Sweep FX knob

Hello all,

I was going to message support to enquire about this but I thought I’d get feedback from the forum first rather than potentially bother the support team during these testing times.

My Prime 4 is new, I’ve had it for about 3 weeks and used it about 6 or 7 times. So far, I’m loving it, it’s easily better than anything I’ve played on before and is far more enjoyable than the Pioneer rigs I’ve played on in the past.

However, last night I noticed that Channel 2’s Sweep FX knob has a strange grinding sensation when twisting it either way. The 3 other channels Sweep FX knobs all feel pretty smooth (or, very smooth in comparison). The knob still works fine, and I wonder whether it’s a case of the grinding will eventually go away with more use, but I thought I’d raise the question and ask if anyone else has noticed anything similar on their units? Everything else on the unit feels solid, I was just wondering whether it could be a sign of damage. I guess I’ll continue using it as normal and see if it improves or worsens before deciding what to do next!

Thanks :ok_hand:

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Is the rotary working at every point, or is it failing to add any effect when it’s turned to certain points, so at say 3oclock position, it’s like there’s no effect at all, but there is an effect at 2oclck and 4 o’clock

Or does it work at every point but just feel Grindy

It’s probably just a grain of grit or sand that’s got in and might be shiftable with a can of compressed air or switch cleaner.



Hey, thanks for your reply!

Yeah, it appears to be working at every point, which is why I think it’s probably not a big issue. I removed the actual plastic knob to inspect the pot underneath and it doesn’t look damaged at all. I had the same thought, maybe it’s just a little dirt that has crept in at some point that’s giving that griding sensation when twisting the knob. I don’t have any compressed air or switch cleaner at the moment so won’t be able to try that for a while due to the lockdown, I’ll have to look on Amazon or something! I’ll keep an eye on it and see if it gets any better/worse. I can’t remember if it’s done it since I first got the unit a few weeks back or if it’s a recent thing that’s started happening because I’ve not used it too much since I’ve got it due to being busy with other things in the studio. It’s definitely one of those things that bug you once you notice though. Hopefully, it turns out to be something as simple as dirt, like you suggest and it eventually disappears!

Thanks again! :pray:

I have the same knob problem with mine P4



Ahh I see, is yours one of the Sweep FX knobs too?? Or is it one of the different knobs, like one of the EQ or FX knobs at the top of the unit? I know you said it’s the same problem, but I wasn’t sure if you were just referring to the same Sweep FX knobs or not.

Great advice. Try a combination of this:

and this:

I did have the same issue with sweep fx channel 4 and its about 80 - 90% better.

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Hi, I also have this “problem” on my second P4. One of the FX sweep knobs, I don’t remember which and even a little the master volume knob turning it from this feeling of sand inside. I don’t think it’s a big deal, or at least it’s not for the operation. It’s just a bit strange the feeling of when you turn it, it’s not beautiful, let’s say. Here it would take the opinion of a Denon technician to give us a direct answer.


Hello I am wondering the same thing can we engage support?

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Mine is occurring on channel one sweep fx knob slightly and pretty intensely on the channel one bass eq knob. Mine is fresh out of the box.

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Any resolution on this for you? It’s definitely bothersome for an almost 2k piece of gear to have a feeling like the knob doesn’t want to twist or is grinding for sure. I’m wondering what to do.

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Hey @Mckhoury1991

I was actually sent a replacement unit for a different issue. The replacement has a similar feel on some of the other knobs, though the worst offenders seem to be the Sweep FX knobs on both units. I assume it’s just from dust/small debris that gets caught up in the mechanism. I could be wrong of course, but I’m not sure it’s a big issue. It just doesn’t feel very nice, especially when paying attention to it. I was slightly concerned when I noticed it with my first unit, but noticing it with my second unit has kind of put my mind at ease. I imagine every user of the Prime 4 will report one or two knobs on their device where the feel has a little more ‘grind’ when twisting. All I can think of is that it is dust/small debris that’s found it’s way in.

As mentioned earlier in the thread, see if you can get something to clean out the worst offending knobs and see if that helps.

Sorry about the super slow reply btw, I forget to log in and check the forum for weeks at a time!

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I had same, brand new unit 1 hour old started grinding on fx knobs. Channel 1&2. Sent it back got a brand new unit. New unit been great.

I did spray some silicone spray down the switch , pull the knob off sprayed it up. Felt better after about 30 mins of use. Still sent it back though.

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Similar problem at my unit, 6 months old, the SweepFX knob deck 2 is very loose, I can turn it much easier than all other SweepFX knobs. Feels strange unfortunately :neutral_face:

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mines exactly the same on channel 2

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This just happened to my Prime 4 as well… Its only a few weeks old… The Sweep FX knob for deck 2 is grinding like sand is in the knob…

Update… I exchanged it out and the replacement works great…

Hey guys, just a little “heads up” if you’re experiencing the “grinding knob” issue. I started having this problem on 2 of my bass knobs, it turns out that the nut that secures the pot worked it’s way loose and had slowly crept up till it was touching the rubber knob making it feel real gritty. Im not saying this IS the problem, but for me it was & a very easy fix. Possible Solution: Pull the rubber knob off the shaft, check if the nut is still secure. If not, tighten it up & you’ll notice the pot feels nice & smooth again. Hope this helps some of you.

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Hello, I have the same problem on the Prime 2 Sweep “Filter” is really bad it makes hatches (on the deck 1) do you think it’s the potentiometer is dead or a fault in the software that controls the “Filter” button? Thanks Grégory