Clipping with thumping sound, but levels look normal (or even low)

Quad Cortex
1

I’m running into some weird intermittent clipping. But my levels are fairly conservative.

I even turned everything down in the path, including the input, output, as well as the blocks.

My CPU’s don’t appear to be overloaded - the CPU meter reads below 50%, and when I look at the DSP diagnotics, it doesn’t appear of the individual CPUs are much higher. They’re pretty well balanced.

Compared to some presets I’ve y’all building, mine are downright simple.

My typical preset includes…

ROW 1:

Adaptive gate (sometimes)

Cory Wong DI (used as comp)

Drive block (the stock XOTIC or BE-OD models with no tweaks)

Phase 95 (I think that’ what NDSP calls it), low mix, low speed.

V2 amp capture (my crunch and lead sound)

ROW 2: Another V2 amp capture for my cleans

ROW 3/4: TC2290 chorus, Cory Wong reverb, NDSP ambient reverb (just the slightest room ambience - always on), Cory Wong delay, and a Freeze >>> I can’t recall what’s on row 3 or 4.

It has been making random thump alongside the clipping indicator. Even after I turned everything down to a whisper level. Occasionally, the clipping will take off like a motorboat. THe only way to stop it is to remove blocks. But that seems to only work briefly.

My QC is mounted to a Metro 20 board 3M Dual-Lok, and my vents have free and open access to air flow. Power supply is CIOKS DC7 with Crux. But this only puts out 2A, where as the NSDP supply is 3A - supposedly the Cioks should be adequate, but I will double check to make sure it’s all setup correctly.

I just plugged into the Neural DSP supplied wall wart to see if it is more stable when it has access to a full 3A.

///

Has anyone dealt with this before? Anything else worth checking or trying?

2

Most likely from the compressor driving your signal too hard or distorting the signal from the amount of compression.

Could also be the gain staging you have within the preset driving certain blocks harder than you may think.

Also the CPU doesn’t need to hit 50% to be full if you’re using only row 1+2. I find it’s pretty full after 40%.

3

I’m certain it’s not the levels, even in the compressor - I turned everything down. Each block is barely passing a signal into the next block (or row).

And I’m using 3 rows (thought it was all 4, but just 3).

I’m currently leaning towards a power issue. DC7 with CRUX. I double checked to make crux was switched over to 12V. But I can’t keep my eye on it all night, so I have my DAW recording with my speakers turned up. If/when it happens, it’ll catch my attention.

My captures were probably a little hot, when I captured them. But they are also turned down drastically. Would the initial capture level influence any clipping behavior on the output like this?

4

Does it make this noise using a factory preset and with nothng plugged in but the OEM power supply, guitar and headphones?

5

That’s up next.

I let it run with the fully loaded V2 preset into my DAW for an hour

Then the same with V1 captures, for the next 15 minutes or so

Then need to pick a factory preset, for an hour - followed by someone’s do-it-all preset.

All of these are with the CIOKS DC7/CRUX though. But I haven’t heard any motorboating yet.

Depending on what the recorded audio files reveal, I’ll repeat the cycle with the QC’s power supply.

6

Well, I’m a little more than 4 hours into this experiment, and not a single thump/clip-indicator or motorboat using the CIOKS/CRUX. I will try again at rehearsal tomorrow. Very frustrating. But maybe something was loose in the power supply connections, and poking around re-seated it(?).

7

Just finished a 4 hour practice session with no thumps/clipping/lights/motorboating.

I was using Neural DSP’s power supply.

So it appears to me that CIOKS DC7/CRUX providing 2A doesn’t quite cut it.

I will have another rehearsal Monday, and will use dc7/crux. Depending on how that goes, I should have a better idea if CIOKS really is compatible. Or if I (hopefully’ just had something loose in the power wiring before Is tarted investigating)

8

How bright do you have the screen and LED lights? I think the brightness of the screen might add more power usage.

Also I would double check that the DC7 and Crux have the proper switches engages for the voltage. I am very curious though if the Crux is affecting the QC with only 2a. But then again the normal power supply is rated at 3a, but of course it’s not because the QC uses 3a ever. They need to have headroom in the power supply so it isn’t running at its full capacity all the time.

9

Would 7nder powering make.those tyoes of noises on a digital.device? Maybe its electric interference from the power?

10

I run pretty clean power in my studio, with a filter/regulator in every rack. I never say never, I’m not an electrician - but I do feel that my power is at least cleaner than most.

When googling this problem earlier, the first item that comes up is to check the power supply. Inadequate power can cause clicking, artifacts, and all sorts of issues.

DC7/CRUX is marketed directly towards the QC. But that was before V2 captures came out, which double the CPU loading. So I’m curious if DC7 truly is the best match.

All I know is that today, with the QC’s power supply - all was well. So the experiment continues.

But then last night, in 4 hours I didn’t record a single event. BUT… I should note that I wasn’t playing for 4 hours last night. It was just turned on through the PA. So I can’t say how, or even if, this impacts the CPU usage, heat or anything like that.

11

I just came across an older thread.

It seems to support my concerns over DC7/Crux. I currently have a Canvas HP power supply on it’s way to me. I will do some more experimenting with DC7/Crux tomorrow night. And then CANVAS HP.

12

Before going down the rabbit hole on power supply issues, I would want to revisit the topic of CPU usage and preset setup.

Can you make a copy of your preset and then take out all the stuff on Rows 3 & 4? Let’s see how much CPU is being used with everything still loaded on Rows 1 & 2:

Also, how are you switching between clean sounds and crunch/lead sounds? Here is an example of a common setup that can cause issues:

Row 1: Input 1 → [amp + cab blocks, etc.] → Multi-Out
Row 2: Input 1 → [amp + cab blocks, etc.] → Multi-Out

Folks who do this tend to switch sounds by using Scenes to turn off the amp and cab blocks on the row they don’t want. But that still means that some amount of clean signal is being sent through that row and straight to the output.

I know you’re sending signal to Row 3, and that the sound issue is with hearing clipping on the output. I’m just wondering if there’s a way that Rows 1 & 2 are being blended together in a way that is causing clipping down the line. Can you share a screenshot or the whole preset?

13

I can try this. I’ve pulled up the DSP diagnostics tool, which shows CPU usage per core. I thought that’s what it showed anyway.

I don’t remember exactly how my routing is setup at the moment, but it looks something like this…

ROW 1: input > phase90 > Wong DI (and/or Wong Comp) > BE-OD drive > V2 capture (high gain).

ROW 2: V2 capture (clean) — this is split from & mixed back to row 1 (a la Steve Serlacci’s video). There’s a blend control on the splitter, swhich I have set to 100% row 2.

I forget which row is actually pointing to row 3, and which blocks spill into row 4 (if any).

ROW 3/4: 2 reverbs, 1 delay (tape I think), 1 freeze, 1 chorus (2290)

///

Additional notes:

  • I find ‘scenes’ to be annoying, I’ve always been a ‘stomp’ guy.
  • switching clean and dirty happens in ‘stomp’ mode. I use the same switch (“E”), to toggle my V2 captures. When the clean capture turn on, the dirty capture turns off. The same thing happens for my reverbs (one is a small ambience, the other is a more lush hall verb).
  • When monitor the DSP diagnostics, it seems to show each core running at or below 50% (I think… if I even am reading it correctly).
  • My overall CPU monitor I think it at about 50% give or take.
  • My V2 captures include amp/cab/mic info. I do not use a separate cab block. I might change this up if I can figure out this popping issue.

So I won’t be home tonight, but I will hop into this tomorrow night, and will report back. If I can figure out to export/save/share my current preset to Cortex Cloud, I’ll do that as well.

14

The noise is probably occurring from the captures turning on/off and feeding into the reverb. The compressor is probably adding to it, it I have noticed on modelers that there can be a weird effect like you’ve described when switching captures (especially hi gain) on/off like that + compression. Just a thought. I definitely experienced that a little even with Line 6 when switching clean and hi gain amp models with them set up as stomps

15

that would seem a little more reasonable, if the clipping/sputtering happened as i were switching.

But it’s not, the unit could be idle. In fact i only use the comp or di for a couple songs in the set.

It could well be happening from some sort of cpu overload, but it doesn’t seem to matter whether the blocks are on or off, or when i switch

That probably would have been useful info to include in my OP. But like i said it’s been happening for at least s month I’m pulling my hair trying every little thing i can

I have a couple more things to check tomorrow night, but i can say that i had exactly zero events when using the ndsp power supply. At the moment, this seems like the most significant development

16

The Canvas HP arrived this afternoon. But something occurred to me.

I actually don’t know how the DC7/Crux combination works. When it says it provides 2A current, is that total current for ALL of the outputs?

My board has the following devices powered by DC7 / Crux

CRUS plugs into…

  • Quad Cortex (plugged into the crux)

DC7’s other ports connect to…

  • Shure GLXD16+ (~400 mA)
  • TC Electronic Polytune 3 Mini (~100 mA)
  • Xotic EP Booster (~5mA) - or - AnalogMan Prince of Tone (~6mA)

DC7+Cruz says it’s capped at 48W max power when used together, but I’m not sure how to calculate the conversion to amps - since QC needs 12V, and the pedals all run on 9.

My assumption is that Crux has 24 Watts to use all by itself (which would be 2A @ 12V). While the remaining ports on DC7 are 660mA for each jack. Again, this is an assumption - does anyone know for sure how that 48W is distributed? Is my wireless sapping current that would otherwise be used by QC?

DC7 is mounted under my board, so I can’t exactly see is the “% of max load” indicator light is coming on.

Google’s AI says QC requires anywhere from 1200mA to 1960mA, depending on screen brightness and CPU load.

I can try dimming my light, but CPU would require more work.

P.S. I first thought i might be my wireless, so I’d already isolated that signal tested that over a period of several hours. All but certain it’s not the wireless clipping.

17

Putting on my electrical engineer hat:

Let’s start with that 48W rating. You can think of this as your “power budget”.

Let’s assume conservatively that the QC takes 24W by itself, or 2A x 12V.

That leaves 24W left for the rest of the outputs in the DC7. 24W divided by 9V = 2.67 Amps left for the rest of your pedals being powered by the DC7.

Adding up: 400 + 100 + 6 mA = 506 mA, a small fraction of what the DC7 is rated for. Or rather, we can say 9V x 506 mA = 4.58W, where there is 24W is available to use.

There are considerations for power supply efficiency, conduction and/or switching loss, etc., but overall, the DC7 + Crux setup should power your entire setup just fine. Sounds like you’re doing everything correctly.

If the problem truly comes down to an issue with the DC7 and/or Crux, then I would submit that it’s a malfunction of the device, and not due to misuse. It wouldn’t be the first time I have heard of Cioks devices failing.

That said, I don’t think we completely ruled out whether there’s a problem with the preset(s) you have set up in the QC. It’s still possible that you may power up your QC with the Canvas HP and have the same issue. Don’t get rid of your Cioks stuff just yet.

1 Like
18

I highly doubt it’s the power supply. Really think it’s something in your preset. Also the DC7 provides more than 2a with all the power outlets

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19

I wasn’t going to toss the DC7, I figured I’d just repurpose for a studio board … for some reason, despite having all the power that Fractl, NDSP, Tonex and Line6 have affordme… I am still hoarding too many pedals, hahaha

To add one more layer to the onion, I did purchase this QC used. It was a recent-ish serial number and in good physical condition. But would there be any value in doing a reset? I assume there is a total factory reset option, and hopefully a soft reset that wouldn’t cost me all of my captures and presets.

As for cloud backups, I do backup my unit. But if the problem is correctable via reset, and then I reset it - wouldn’t I be resetting to the ‘corrupt’ code? I can good the reset instructions - but I’d be guessing as the second half of that question.

20

Getting back to this…

I made two copies of my preset

  1. CONTROL - 47% overall CPU

  2. CPU TEST - One at a time, I deleted everything except for one ‘row’ at a time. Including splits&,mixers

ROW 1: Simple Gate > MX Phase 95 > Exotic (overdrive) > Wong DI > V2 high capture (plus one split/mix) = 23%

ROW 2: V2 clean capture (wrapped in the split from row 1) = 17%

ROW 3: Wong The 80’s Chorus > Wong Delayyy > Wong the Wash Verb > and a split/merge down to row 4) = 15%

ROW 4: Room Reverb > Freeze 9inside a split/mix from row 3) = 10%

ROW 1&2 TOGETHER = 35%

ROW 3&4 TOGETHER = 19%

The outputs from ROW 1&2 are directed to ROW 3. The output from ROW3 is ‘multi-out’. ROW 4 output is not assigned (it simply mixes back into row 3 before it hits the output.

My preset is uploaded to the cloud…