New Mod Duo user having difficulties


I have had my Mod Duo for around two weeks. Having tested it, i found few problems when connected directly to an amp. In the last few days, I have updated some elements (new audio interface and monitor speakers) in order to move form using a physical amp to using Amp simulation. I have added

Focusrite 4i4 Gen 3
Pair of M-Audio BX8 monitors.

If I connect directly to the monitors, all is well. However if i connect via the 4i4, i get substantial interference/noise.

I have ensured my supply is as clean as possible and tried to avoid earth loops. I have tried a laptop as well as my desktop and tried my old audio interface (Line 6 UX2). I am unable to get rid of the noise.

I am also having difficulty setting acceptable gain levels, especially on output. Even at what I consider to be low(ish) settings, I am getting red flashing LEDs on the output stage. At the moment, lowering the input and output gains to get the Mod Duo to ‘behave’ means turning up the input gain on the 4i4 to the point where the interference is intrusive.

I have spent 3 days checking and changing my room layout to try to minimise the impact of this, but it’s still there!

Also, does the Mod Duo go into ‘bypass’ mode when switched off? I touched the end of my guitar cable with the Mod Duo powered off, and still got a buzz throught the 4i4.

Apologies for the long post!



Hello @johnbury,

I will try best to answer the few questions you have, but someone with more knowledge might chime in as well.
Please see this Adjusting volumes post in the wiki and this forum post for a little diagram how gain is handled inside the duo.
It is common to set a gain or compressor plugin with adjustable volume as the last plugin in your pedalboard to avoid too much digital gain before digital to analog conversion.
As stated in the wiki the mod duo has a true bypass

Feel free to use the search function within this forum and to ask upcoming questions.

Hope that helps and God bless

1 Like

Hi @mj_prod

Thanks you for your very prompt response.

I have read the Wiki in relation to setting gain levels, however, I have a very recent Mod Duo, and the UI appears to have changed and no longer reflects the Wiki content. From the main menu, the ‘system’ entry now shows an ‘Input’ and ‘Output’ Menu. Entering these, I only see the ability to change the gain for one or both channels, this being shown as a percentage. I have not found a ‘Stage’ nor ‘Fine’ menu option. (Headphone volume appears under ‘Output’ menu).

Your post also included

It is common to set a gain or compressor plugin with adjustable volume as the last plugin in your pedalboard to avoid too much digital gain before digital to analog conversion.

I’m not sure I understand this, but I will experiment to see if I can make it work for me!

As for ‘True Bypass’, I admit I did miss that! My old pedal board had a mix of pedals with and without ‘True Bypass’, and I am used to getting no signal if the power was off! Thank you, I have learnt something.

I have learnt my lessons in the past and do look for answers before I post. The results of my searches showed others experiencing similar issues but not many concrete solutions.

Many thanks for taking the time to reply.

Best regards





I have an update.

I have tinkered with gain/volume settings and the use of a gain plugin on my pedalboard(s) and have achieved some success. I am now able to get a decent volume through the mod duo and have been able to keep audio noise to a lower level. The noise is still too high, but I can get by for now until I find or am advised of a better solution.

It would appear that, in the past, creating a new pedalboard started a board with a gain plugin already selected and connected, this is not what I see on my device. Shame as automatically adding the gain plugin would be helpful to newbies like myself.

Thanks again for the information you provided in your response… I have moved forward!




I just took delivery on a new Mod Duo, and am finding the differences you name as well. I’m not very encouraged by that. Already I’m finding the device difficult to use.

Currently I am trying to find out how to make sound come out of both earphones. Accessing SYSTEM>OUTPUTS>HEADPHONES VOLUME - does no good. Checking out the Inputs doesn’t help either.

When I attempt to create a new pedalboard with devices on both channels, I still only get sound from one earphone.

I notice, also, trying out the preloaded pedalboards, some only transmit sound through one earphone.

is there any case where you get sound of both earphones?

I am wondering if it is only headphone, or perhaps output levels being muted or low on a specific channel.
if you connect the regular outputs to some audio equipment or speakers, do they get sound on both channels?

there have been a lot of changes in the wiki recently, we are in the progress of writing the documentation there.
feedback welcome, of course

Did you also check the Output levels for channels 1 & 2 in settings? This happened to me once when one of the channel Output gains was turned way down. Also IIRC there is a setting in the Web UI to copy mono output to both channels.


Original poster here!

I have (I think) resolved my issues. I haven’t done this in a scientific way and so cannot identify a specific action that fixed things for me.

Things I did were across several areas and included:


I turned off dynamic CPU speed settings in BIOS. This removed a lot of interference especially when connected by USB.

Rebuilt my PC removing hard drives, moving content to the cloud and installing SSD as my main system drive. Also rebuilt Windows 10 to remove accumulated dross. My PC is so much quieter and boots very quickly

Relocated PC to one end end of my desk area.


Moved it as far away from the PC as possible.

In settings I adjusted input gain to remove/reduce clipping. Adjusted output gain to 100%, adjusted headphone volume to 90%
Made sure I always use a gain control as the last item on pedal boards.

I can now get good volume from my set up with minimal noise

I am now much happier and feel the Mod Duo is living up to my expectations.

Hope this helps!