I was unable to resolve noise in the Mod Dwarf after trying DI and groundless power

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I’m experiencing similar noise issues on the Dwarf outputs to @DaybridgeGhost. On the headphones output (either with output jacks connected or not) there’s no noise, even with the output gain and headphone volume at 100%, other than a tiny bit of hiss that’s to be expected with everything maxed out. Meanwhile through the output jacks there’s a lot of digital noise. I’m not experiencing a typical 50/60Hz mains hum noise, this seems to be mostly generated by the Dwarf itself.

The noise has several different components - the main one is a constant tone at 375Hz, which seems to be related to the buffer length, since

  • 375 = 48000 / 128
  • it drops an octave when I switch the buffer to 256 samples

I’m on release v1.10.3.2360 and have tried the “Compensate Ground Loop” setting - this definitely reduces the level of the 375Hz tone but the other components of the noise seem to be unaffected.

I’m currently working through different combinations of balanced/unbalanced, high/low impedance, grounded/lifted to find the best one - I’ll post some results here once I’m done.


Was thinking about getting the dwarf after my mod duo x went back for all kinds of booze issues

Am scared now, my friend solved with a transformer isolating the output -

Yeah, seems like a transformer is needed. I’ve got very good results using a passive DI box connected in reverse as a balanced-to-unbalanced isolating transformer, i.e.

  • TRS jack to XLR cable from the Dwarf output to the DI box output
  • regular TS jack cable from the DI box input to the input of the amp
  • DI box ground lift switch set to “lift”
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I’m going to try a few more tests and a different 12V/2A power supply. If that still does not work to lower noise, I will reach out to support. I super appreciate everyone taking the time to help me with this!


Tbf, despite the noise I am experiencing, this is a spectacular device. I played a show last week and while the noise was definitely present, it wasn’t too noticeable in a live setting. I think once I manage to resolve the noise issue, it will be great for recording too!


Thank you @bassyben for sharing your findings. This really help us finding more suitable solutions and improving our range of suggestions for users facing similar issue.

@DaybridgeGhost thank you a lot for the nice feedback.

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So - there’s a lot of combinations! To keep this post reasonably short, I’m focussing on connecting the Dwarf to a typical amp input (unbalanced, high impedance), since that seems to be where the biggest problems lie. Rather than going through an actual amp which might have introduced its own noise, I plugged directly into my audio interface with instrument mode on. I wanted to focus only on noise on the Dwarf’s outputs, so I left the inputs unconnected and input gain at 0%.

The short version
A re-amping box works well for connecting the Dwarf to an amp without getting digital noise induced on the outputs.

The long version

I tested three different types of connection:

  1. a jack lead directly from the Dwarf’s output to the interface’s input, with:
    a. TS connectors
    b. TRS connectors (note that this does not create a balanced connection since the input is unbalanced)
  2. a passive DI box connected in reverse between the Dwarf and the interface, i.e.
    Dwarf → (TRS jack to XLR) → DI box → (TS jack lead) → interface
  3. a re-amping box connected in between the Dwarf and the interface, i.e.
    Dwarf → (TRS jack lead) → re-amping box → (TS jack lead) → interface

For both 1a and 1b, the jack lead’s shield was connected at both ends (i.e. grounded). 2 and 3 were both tested with ground connected and ground lifted.

Test equipment and conditions:

MOD Dwarf

  • Output 1 to audio interface
  • Output 2 not connected
  • Outputs 1+2 gain 70%
  • Headphone volume 0%, headphones not connected
  • Inputs 1+2 not connected, gain 0%
  • USB not connected
  • Ground loop compensation ON
  • Buffer length 128 samples
  • Pedalboard loaded with test tone generator (440Hz sine wave at -6dB, muted during recordings)
  • Powered by the stock, earthed power supply

Audio Interface: Focusrite Scarlett 4i4 connected to laptop.
All recordings made through Input 1 with:

  • Instrument mode ON (unbalanced input, 1.5MΩ input impedance)
  • Gain adjusted before each test so the test tone registers -6.0 dB on the input meter, to ensure recordings are comparable
  • Air mode OFF
  • Pad OFF
  • 48V phantom power OFF (irrelevant in instrument mode anyway)

DI Box: Samson MD1 Mono Passive Direct Box

Reamping box: Orchid Electronics Amp Interface (following a tip from @QuestionMarc in another thread)

Connection Peak noise level (dB) Description Recording (boosted 48dB)
TS jack lead -49.6 Digital (inc. 375Hz) + hiss MOD Dwarf output noise tests - TS jack lead INST.wav
TRS jack lead -53.5 Digital (inc. 375Hz) + hiss MOD Dwarf output noise tests - TRS jack lead INST.wav
Reverse DI box, grounded -77.5 Hiss, high frequencies attenuated MOD Dwarf output noise tests - Reverse DI grounded INST.wav
Reverse DI box, ground lifted -77.0 Hiss, high frequencies attenuated MOD Dwarf output noise tests - Reverse DI ground lift INST.wav
Re-amp box, grounded -48.3 Digital (inc. 375Hz) + hiss MOD Dwarf output noise tests - ReAmp grounded INST.wav
Re-amp box, ground lifted -64.7 Hiss, full range MOD Dwarf output noise tests - ReAmp ground lift INST.wav

Based on the numbers alone, the Reverse DI box looks best, however numbers don’t tell the whole story, as the object here is not just to get the lowest possible overall noise level but to eliminate, if possible, digital noise induced on the outputs while affecting the output signal as little as possible. The reverse DI recording has noticeably less high-frequency hiss than the re-amped signal - the question is, will the high frequencies of the actual signal be reduced as well?

To test this, I recorded the output of the CAPS White Noise plugin using the reverse DI and re-amp methods, and also using a TRS jack cable direct to the interface but this time with the input in line mode (and therefore balanced). Again, the gain was set for each recording so that the 440Hz test tone measured -6.0 dB on the input meter, to ensure the recordings are comparable:

  • 0 - 3 secs : TRS jack lead, line level, balanced
  • 3 - 6 secs : Re-amp box, ground lifted
  • 6 - 9 secs : Reverse DI box, ground lifted

MOD Dwarf output noise tests - white noise - TRS line, ReAmp, Reverse DI.wav

This sounds a lot like the previous recordings of hiss but remember that now we’re listening to the output of the White Noise plugin, i.e. this is the signal, not the noise. The re-amping box sounds indistinguishable from the balanced line level recording (to my well-worn ears, at least), whereas the high frequencies of the signal are noticeable attenuated for the reverse DI box method. This isn’t really surprising, since the re-amping box was designed to be used exactly like this and will have had its transformer selected accordingly. Meanwhile, the DI box is getting the signal pushed through in the opposite direction to what it was designed for, so who knows what impedance mismatches are going on.

This high-frequency attenuation explains the apparently better noise figure for the reverse DI box - since it’s attenuating all high frequencies, signal and noise alike, the overall recorded noise will be lower in volume. However, the high frequencies of the signal will also be similarly attenuated, so the re-amping box is actually giving the better performance. Most importantly, the digital noise is gone.



Thanks SO MUCH for your careful testing and apologies for the late response. I was finally able to go through all the files and agree with you assessment of each one.

I only need to point to a couple of things:

The reverse DI option is not wrong per se and is often used in the absence of a balanced to unbalanced conversion device. To assess whether or not high-frequency signals are also being filtered, one must use a spectrum analyser to tell for sure, though your ears can probably tell you something.


in this particular case there is no impedance mismatch happening: the unbalanced side is connected to the amp and the balanced to the Dwarf.

The main issue with using a reverse DI is that it tends to weaken the signal quite a lot. Other than this, there is no evil in doing so.

There are some boxes in the market that are “full duplex” so to speak – either balanced or unbalanced inputs and outputs, but those cost a lot of money.

With Focusrite units specifically, using the INST mode increases the gain range from -10 to +36dB to +13 to +60dB (!!). Also, the noise floor raises from -90dB to -87dB. This will certainly produce more noise and hiss from effects.

INST should only be used with the instrument directly connected to the input of an interface.

You were very careful to keep input signals at the same level for comparison’s sake.


Thanks for your reply @QuestionMarc, great to have your input on this!

The reverse DI option is not wrong per se…

I absolutely agree - it’s worth noting that my DI box is a pretty basic model (around GBP£40 new) and I’m sure there are high end ones that would perform much better on high frequencies.

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I’ve been having noise issues with my Dwarf as well. I’m using it on the master insert of my Allen and Heath Xone 96. The output of the device does not change the amount of noise. Seems to me like the digital electronics internally aren’t being filtered out of the signal properly. Unfortunately for me I don’t have the room or want to start using DI boxes and other adapters to have the Dwarf sit on my master insert.

I’ll see if I can do some more testing to find out what frequency my noise is at. I’ve already tried various different power scenarios with no avail.

Are you using the supplied psu?

Yes I am and just for testing purposes I used another supply with same polarity, voltage, and current rating and heard the same noise.

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Have you tried the ground loop compensation feature?
Also the noise gate coming with 1.11 seems to be working really well on that

I’ve been having noise issues with my Dwarf as well. I’m using it on the master insert of my Allen and Heath Xone 96. The output of the device does not change the amount of noise.

Hi there,

I hope I’m not breaking any rules by reviving this thread but I am currently using the MOD Dwarf in a similar way, as an insert on my audio interface, and am experiencing the same issue.

The reason for using the device in this way is because as part of our live setup we’re using a Shure Beta 87 (which needs phantom power) and so we’re using a a mic channel on the interface to power the mic and send the signal out to the Dwarf (with the input gain on the Dwarf at -12db, as the signal already has ample level and I’m sure preamps on our Clarett+ are quieter than those of the Dwarf), for the processed sound to return in stereo to the interface.

We’re using balanced cables and the supplied PSU plugged into a Furman P-1400 AR E (as is the rest of our setup).

We’ve tried the ground loop compensation feature and it has no impact on the noise. I’ve recorded the sound and uploaded here: Stream 01 - MOD Dwarf Noise - 220405 1059 by Kevin Reginald Cooke | Listen online for free on SoundCloud. We used the noise gate in order to get through our first gig with the device but would much prefer to eliminate the problem altogether.

Did you find a solution to your problem @Kennymester?


Not at all :slight_smile:

Have you tried to use passive DI or balanced cables?
Take a look at this troubleshooting guide and let us know if anything helps.

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Hi Jon,

Thanks for the reply! I’m already using balanced cables both for the input and the L/R outputs. I haven’t tried groundless power, actually. I’ve ordered a new power supply and hopefully that will do the trick…


You’re welcome @kevplaysbass :slight_smile:

Please keep us posted on your results

I had similar issues in my studio going into audio card. Changed power supply which helped somewhat. Ran through audio ioslators and DI boxes, balanced cables etc but if I have the Dwarf plugged into the USB so I can use the editor its mighty noisy again!

The work around is I program it to do what I need it to and then unplug the USB to the PC and the noise drops off again.

Just think its a crazy earth design fault but YMMV on this one, Its the only device I have that has this issue thankfully. Might invest in a USB filter next but for a box that is meant to be replacing stuff it sure gets busy with stuff required to keep it quiet.