Your description seems that you are facing a ground loop issue.
Anyway, have you reached out to support@moddevices.com?
Please do it, add your serial number and a sample of the noise if you can.
Iām sorry to say this but in my studio I have Pa equipment, guitar amplifiers, effect pedals, multieffect pedals, keyboards, midi controlers not to say more. All my equipment shares the same earth connection and as expected never had a ground loop problem. When I first conneted my Mod Duo X, problems arrived. You tell me, the problem is your electrical infrastructure. So, due to luck,the rest of electronic equipment doensāt suffer with the problem or by some development problem the Mod Duo X, ground is not necessarily a connection to the real earth, but rather is a reference point to 0 Volts? You have to do a little more then workarounds like, using a TRS cable when your amplifier has balanced inputs or putting a DI box in the middle. Ok, that is a a good way to solve the problem in existing units but what will you do in the future?
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Yes. It takes part in the equation certainly.
Not necessarily luck. It may be the case that with all the gear together and with the placement of devices in your chain (both audio and even electric), the MOD DuoX is the one that āshowsā the issue. Thereās not really a āone solution fits allā here or even a reason. I can tell that just this weekend, I had one gig where we were using a MOD Dwarf and a MOD DuoX, both of them were fine regarding noise without using balanced cables or even a DI, but a hold MacBook Pro used for backing tracks was with a huge noise while connected to the power. This never happened in any other venue, studio, or rehearsal space where we used it.
We are constantly searching, trying, and implementing fixes on the software side to minimize these issues on all the cases that we could pinpoint the reason and find one usable solution. This applies to all production and already sold devices since itās a software update.
Itās also something that we keep a close look at each product that we develop. But again, more users, more use casesā¦this results in more triggers for this type of issues found.
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Thanks for the answer. I know that you are constantly working to get better. We can see that on the many updates released. My unit it a Mod Duo X Limited Edition from 2019. I didnāt mentioned but, if I remove the ground connection from the power supply plug I have the same effect of DI or balanced cable - no ground noise. Other problem is the low frequency noise on outputs 1/2 when the amplifier is regulated at more or less 50%. The workaround is to regulate the gain stage of DuoX near its maximum and lower the amp gain to minimize it. On the other hand I get more white noise in silent parts of the music.
Unfortunately not all issues can be minimized efficiently minimized by software. Sometimes the hardware rules the game.
All said, you have done a great job with this thing. I love it with all its issues (who doesnāt have one?). Keep the god job.
(BTW Iām happy to see portuguese people like me on the Mod Devices team (am I right 
?))
JosƩ Mendes
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Thereās dozens of us! 
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This is actually an important point on this matter. The MOD DuoX LE was a small production edition and, as you probably know, we are aware of some issues that popped up on those units.
Not answering yet on anything of your issue (I can do it later), Iām not sure if you had the chance to read this post from @friedsilence back in November. Let me know if itās something that you are interested on.
Indeed it is true and your case is actually a really specific one on that. We released a device after that was tackling some of the issues from the LE edition.
Thank you for the nice words. We always try to do our best. Sometimes that is not enough, but we always try 
haha sim We are everywhere for quite some years haha
JoĆ£o Neves
As a good Portuguese joke @falkTX and @XLooper: a lot! more than one!
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hey guysā¦ sorry to bump an old topic, but seemed to make more sense than starting again! 
note that i am not referring to ground loop issues here, but rather specifically the periodic low thumping noise that a few folks have written about. with ground loop issues resolved and with good gain-staging, such that both my input and my output signals are close to 0, these noises are at most around -50dB. as such, many folks will have not noticed them and they might be, arguably, within an acceptable range for a lot of use cases ā i suspect thatās why this specific issue hasnāt been reported widely.
however, i do a number of things in which silence and low level signals are important, so it has been an issue for me from time to time.
i recently made an important discovery:
if i have a flashing button (i.e. a button assigned to tap tempo), the thumping coincides with the flashes of the button LED. if i change the LED Brightness setting to LOW, the thumping drops about 20dB ā that makes a huge difference, and is acceptable for most of my scenarios.
note that there is also a low-frequency ārumblingā associated with rotating any of the encoder knobs; unfortunately no adjustments to the display settings seems to affect that noise. however, it is a lower level and only happens when knobs are moved.
my unit is a Duo X LE. i canāt say whether things are similar on a full production run Duo X.
hope it helps somebody out there!!
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hi @Kim !
at least for me, this particular low level, low frequency thumping happens whether USB is connected or not. ā¦and itās sufficiently better, both with USB and without, when i change the LED setting to LOW.
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