[solved] High noise level at all times

Using MOD devices
#332

hey @jon , I appreciate your detailed response. Just one last set of questions and I think I’ll be okay. Sorry for dumping these questions on you, but I don’t have experts on this stuff around me, so thanks for putting up with all the questions.

So is a DI (at least the one you sent me, which has a circuit diagram) and an isolation transformer, basically the same thing plus the fact that the DI has a ground lift? Apart from the whole impedance matching thing.

So, if an isolation transformer would remove the noise, so would a DI (even without ground lift) right? Or could the impedance matching change the result somehow?

I read some discussion from @QuestionMarc that ground lifting could be dangerous, which was why I was looking at isolation transformers (which seems pretty expensive). But if it’s true that they’re basically the same thing, I guess it wouldnt matter except the inconvenience of a big DI box.

Thanks

1 Like
#333

haha I’m here exactly for that, so you don’t need to be sorry.

I will be honest with you, technically I’m not sure if they are the same thing and maybe someone else can give you more technical input. Yet, for the porpoises of your issue, I believe that the results should be identical.

I believe that having the ground lift feature, in this case, will give you more possibilities. So, if simply the DI doesn’t solve your issue, you can try to switch the ground lift and check if that does solve the issue.

#334

Hi @semmo
sorry to jump in here again, but maybe I can help.Maybe I’m just writing some things that you already know. I also had problems with noise in the beginning, but my Dwarf now works completely without noise. I have done three things for this:

  • I bought a different power supply (which I only sometimes use. In most cases I take the original one, sometimes the new one is needed). [solved] High noise level at all times - #306 by Kim
  • I made settings in the Settings-Menu for Input-Gain, NoiseGate, Output-Gain, Pedalboard Output-Gain and Compensate GroundLoop. You can adjust a lot here and remove a lot of noise. Just turn the buttons and get a feeling what is really heppening with the noise.
  • Then I took care of the gain staging. I noticed that the plug-ins have significant differences in volume (some are very quiet, some are overdriven). I think these differences are a tribute to the open source approach: it’s just not one manufacturer that makes the plug-ins, there are many. And each one has its own settings… I have then built a Gain Control plugin into my pedalboards not only at the end , but partly also in between other plugins, especially those that seemed very loud to me. I then turned some of them down a little bit and I managed to remove the noise from all the pedalboards that way.

What I can assure you is that you can get the Dwarf completely noise-free.

3 Likes
#335

Hey @Kim , thanks for your help.

  1. I guess I will try to get different power supplies if they help, but I wish I knew what about the power supply is the problem exactly.
  2. I own a Duo X, and it seems that there is no compensate ground loop feature. @falkTX , is there a reason for why the Duo X couldn’t have the same feature?
  3. My problem persists even when there are 0 pedals (only gain), so I feel like that’s not exactly the issue here.

So I’m guessing that for your Dwarf, you did not have to employ a DI box/isolating transformer/lifting ground at all to remove your noise? That’s strange, it seems like it must have been a different issue to mine. Bummer :frowning:

#336

Hey Semmo!

I am a guy who went through all sorts of noise hell in the beginning.

First, I want to touch on the MDX; there is a noise gate in the settings, but needs to be applied to the inputs manually:

20230404_081619
20230404_0816191920×1440 135 KB

Start with this, and see if it improves.

Now, I’ve tried it all to solve the noise.

Spent 1k on a medical grade isolation transformer, returned it.

Had a passive DI and a ground lift, both returned.

What solved the problem for me, was a new groundless power supply ($13), and learning about gain staging within my personal setup (especially gain staging on my bluebox) and on my boards.

Can I ask what your I/O gain settings on your MDX?

Originally my gain was wayyy too high at the MOD unit. Drastically raised my noise floor at higher input gains.

What is your signal path, and how are you recording?

Are you recording directly from the MDX, or is it being used as a send and return?

I had bad gain staging at my mixer, and that added a lot of noise to my send channel. By the time it returned my recordings were over juiced and sounded bad. I fingered the dwarf as the culprit, but three fingers were pointing back at me lol

I use -3dB on the inputs, and -6dB on the outputs for my particular needs. I run a monosynth on input 2, and a microphone on input 1 (used for video/audio sync)

I genrally boost the audio with a gain plugin internally, or at the output, but only until my LED indicators are in the high green or yellow range.

My MDX routes into my OT2 input and is mixed there. The master out enters the Dwarf, and is mastered using RMPro, and then recorded from there into an audio interface. For the most part, I do my adjustments at my OT2 mixer, or at the interface itself.

Its a little bit of a process, but I’ve gotten my boards really quiet for 99% of the ones I’ve been working with recently.

I’ve noticed very little noise in my recordings compared to my first several months lol

3 Likes
#337

i’ll just note that, with respect to minimizing MOD self-noise specifically, it’s best to run the outputs at 0 because the self-noise does not change with the output level setting. so setting the output as high as possible gets you a better signal to noise ratio, with respect to noise which is endemic to the device itself.

your ability to do this, of course, depends on whether that output level works with gain-staging requirements further down your chain of equipment.

2 Likes
#338

Usually I run the outs on zero for the most part. My last recording needed some tweaking.

Actually, I just tweaked my settings and gain staging to address the output. Had to adjust some levels in the internal mixer on my board but it seems to mix out really well in the OT2

1 Like
#339

the Duo X always has it enabled. on the Dwarf it is optional as it otherwise overheats, that is why we reduce the cpu clock speed with it enabled.

4 Likes
#340

A D.I. And a line isolator are NOT the same thing, and either one can have a ground lift so that’s not the differentiator.

They both take an unbalanced output signal and convert it to a balanced signal; the difference is that a D.I. has a higher impedance transformer which typically results in a built-in -20 dB signal drop, frequently with a pad available to take that to -35 dB. That’s great for taming the high impedance signal of a guitar or bass, but bad for going out from a digital modeling pedal because many of them already have low-impedance outputs. That’s where the line isolator comes in, it balances the signal without dampening it.

Of course the Dwarf already has balanced outs, so a line isolator isn’t strictly necessary (just a TRS to XLR adapter), but it can’t hurt.

3 Likes
#341

Thanks a lot, @RashDecisionAudio! As I told, I’m not really an expert on the matter and you just granted the thing of the day that I learnt :slight_smile:

3 Likes
#342

Thanks @jon and everyone (@Elk_wrath and @plutek, @RashDecisionAudio). Unfortunately, the noise level is still high and not going away. I bought a DI box and put it before/after the Duo X, and the noise still does not go away, EVEN with ground loop lift feature.

At this point, I am fairly certain that this is a power supply + problem with Duo X’s poor circuitary, not a ground loop issue or anything else. Here’s why I think this is so.

  1. With the Duo X turned off, but plugged into a power supply, signal chain is guitar → Duo X input 1 → Duo X output 1 → Audio Interface/Amp, there is significant noise, but there is NO noise when the Duo X is NOT plugged into a power supply. This basically means that the bypass is not working properly, and some of the fluctuating AC current from the wall is somehow seeping into the signal. This should be not happening. I think there’s issue where the noise from the power is allowed to seep into the signal, even when it is supposed to be bypassed. I can’t see where the fault could be except for the Duo X’s circuitry itself. It is seeping in even when it is ‘supposed’ to be isolated (bypassed), and it is much worse when the unit is turned on (probably the noise is amplified, but also more places for the noise to seep in I presume).

  2. With the Duo X turned off, when I plug in different power supplies DC power adapters with 5.1mm/ 2.1mm outs (with varying voltages/amperes, one that was 24V 1A, one that was 12V 0.5A, 10V 1A, etc.), I found that the noise level varies. Particularly, I found a power supply that I bought for my amp a long time ago, which left the Duo X with NO noise. Unfortunately, this power supply is 9V 300mA, which means it can’t power the Duo X turned on. But from this experiment I was able to figure out that the power supplies are causing this issue. (Or could it be that lower current=lower noise? I have no idea…)

  3. The problem with 12V 2A is that there doesn’t seem to be a demand for super high-quality power supplies for this spec, so buying power supplies is basically a stab in the dark every time, I’ve been through like 3 power supplies already but haven’t found one that does not make noise yet. I don’t even know what keywords I need to use to find one. I think I probably would have to find one with an isolation transformer inside of it, but I don’t even know if anyone makes one. I’ve ordered a couple more candidates for power supplies but I’m not even sure if it’s going to fix it.

Please let me know if my conclusions are incorrect.

2 Likes
#343

Hmmm,

I can’t get any noise out of my MDX in my current set up.

Output is at 0dB, and master volume bumped to 20dB.

20230405_113725
20230405_1137251920×1280 138 KB

20230405_114242
20230405_1142421920×1262 164 KB

Even octatrack at highest gain and volume settings.

20230405_114036
20230405_1140361920×1240 121 KB

The USB audio in comes directly from the dwarf through my audio interface. So I have 2 MOD devices in my hardware setup and both are in the same signal path without noise.

I have to wonder that due to my “Studio” set up, filtered power strips, balanced cables, and third party 3A power supply prevents me from being able to replicate the issues that a gigging musician faces.

20230405_114440
20230405_1144401230×1548 177 KB

I just use these cheap groundless PSU’s from amazon, and that helped me out my initial struggles.

#344

huh… this is weird and interesting. i wish i could test it; unfortunately my Duo X is one of the initial SE units with no power switch. :frowning:

in the meantime, perhaps someone from the MOD team could chime in with details about what, exactly, the power switch disconnects when it is in the OFF position? that might give us some clue about what is important in a power supply, in order to reduce noise…

what type of cable are you using here, and is the input you’re plugging into balanced or not? or, to look at the question another way: do these observations change if you switch your output cable between a balanced type and an unbalanced type? yes, i know the output circuitry may not be properly feeding the +|-|GND of a balanced connection when it is not powered, but there still may be differences in how various circuit paths are coupled, depending on which cable type is used. …again, this would need more detail from hardware designers at MOD, to help sort out what any such observations might mean in a Duo X with a power switch set to OFF. :thinking:

1 Like
#345

The observations does not change when I switch the cable from balanced to unbalanced, nor if I put a DI box in between. Also, my device is a Duo X, not a Dwarf.

2 Likes
#346

yep… brain fart, just corrected! :stuck_out_tongue:
…i got enchanted with the imagery of a Dwarf without (Magical) Power. lol

2 Likes
#347

@semmo sorry if I missed that part but did you tried it without the usb interface?
Only other option I use that you could try is 12v USV like that Tecnoware mini

2 Likes
Mod dwarf, very noisy background signal
#348

For me happens that thru headphones sounds awesome,but when i connect an output is sounds very very different , so headphone was not an option for me to make sounds :see_no_evil:

1 Like
#349

Yep, on the label of your PSU there is an icon “square within a square” : meaning double-isolated. I tested my original PSU shipped with Dwarf with a multimeter: the ground AC pin has continuity with both DC pins; potentially causing ground loops, especially when patching other effects with it. My other adapter Moeer (for Micro Power brick) 12V@2A:DC - is double-isolated.
I ordered a Zoom AD-19 adapter: 12V@2A:DC + and it is double-isolated.

[ADD] Another option is RockPower (by Warwick) 12V@1500mA : DC + . No indication if double isolated, but continuity check with multimeter is luckily negative. I believe power adapter SMPS technology will always utilize a double insulated transformer.

3 Likes
#351

This was a long reading (I couldn’t finish it). But thank you all for the clues, you help me fix my Mod Duo X noisy setup. My solution:

2x Passive DI (Behringer HD400), one before the input and one after the output
1x cheap 12v power transformer, I actually found and old one that I didn’t even remember that I had

System up and running and no noise at all even with the USB connected
Having 3 factors of noise combined was a little tricky

9 Likes
#352

Hi! Maybe this could be useful for you:

Bye!

1 Like