Amp models compared?


Hi everyone

I have been looking at the mod-duo for a while. I am a happy user of a Zoom G3. I am disappointed by the G3n’s direction so I am looking what will be my next toy.

I find very attractive the flexibility of the signal chain. I have seen some examples where the foot-switch can be used to go one path or the other, and that would allow me to do things I can’t do right now with the G3. Not to mention MIDI.

About amps

  • Does anyone have an opinion on how the Guitarrix and other included Amp simulations compare to other Amp modelers, both low end (G3, Mustang, etc) and high-end (Axe, Bias, etc). Are there any comparison videos you know about?
  • I have read that amp modelers use quite a lot of cpu. Is this something that would affect a practical setup?
  • With the G3, I can’t do things like having a clean Marshall and a driven Marshall in the same patch. I would need to put two amp sims and quickly turn one on and one off. Can the duo do something like this? eg. by using a Switch (associated to the foot switch) that would send the signal through two different paths, each one with an Amp sim with different parameters? Would having the Amp sims even if not used at the same time affect the cpu usage?

About MIDI

  • I use a FluidSynth plugin in Ardour that allows me to take my SR-16 and use it with a SoundFont. Is this possible in the Duo? Can I use drum SoundFonts and have the SR-16 inject the drums sounds into the signal?
  • Is there a plugin that can be used as a looper?
  • Are there any other nice features around this eg. syncing with looper with the drums?

About the project
I have seen the projects for mod-ui, mod-host and others. I managed to run them on my desktop.

  • Is the buildsystem and process used to build the firmware image available?
  • Is it possible to rebuild your own firmware image?

About the hardware

  • I read a post about problems with background noise. Is there any progress fixing this?

Thanks, and sorry if those were too many questions.


I am a bass player and so I can’t say too much about guitar sounds and how the Mod is working for guitar.

I’ve bought the Mod Duo because I am using Linux as a DAW since many years and was thrilled with the potentials of using my “DAW plugins” live on my bass. Another aspect would have been to use the Mod Duo to explore some new sounds and some new effects I’ve never really used on the bass.

As a multi effect the Mod Duo works fine. You are EXTREMELY flexibel and there are hardly any limits. There are many plugins with variable quality (some are great, others have bugs or are not what you’ve like to have in a great effect processor). Then there are the unstable plugins - in my experience the rough ones in there are really rough, but there are some diamonds in there and some of the stable pluings are equally bad to me. It’s great for people who like to tinker around and try create new ways of using effects.

I am using a preamp / power amp combo and tried to use the Mod Duo as an alternative to my pedalboard and my preamp. The signal path would be bass guitar -> Mod Duo -> Power amp -> Bass speakers. This is working fine, but my preamp (Aguilar Tone Hammer) sounds better. I’ve tried some different amp models, but I haven’t found a way for me that to sound as great as my pedalboard together with the Aguilar Tone Hammer.

If you are a person who wants something that works plug and play, then I’d say that the Mod Duo will not work for you right now. There are some pedalboards you can try out but there are not presets like in most guitar modeling amps. There are no presets for a Marshall Sound or a Mesa Boogie Rectifier sound. There is the guitarix amp and other modeling amps - but at least for me they were not as quite Plug and Play as with “classic” amp modeling pedals.

Some answers to your questions:

  • the background noise is no problem for me. Maybe my bass sound is not as HiFi as the people who have problems with it. Connected with a computer there may be background noises, but standalone the Mod Duo works great for me
  • There is a looper plugin but I think it’s not good at all. I get constant clicks and pops with it. It seems to work for some people (there is a bass guy in this forum with great videos) but for me it doesn’t work at all compared to my Boss RC-1
  • The new solution for different states of a pedalboard are pedalboard presets - but in my test I had pops and clicks when I was changing between pedalboards. So this isn’t working for me either right now. The older solution would’ve been to use switches on the pedalboard (then you would need to Marshall instances) - but then the CPU power can become a problem (and the pedalboards tend to get messy).

for me the Mod Duo is a project with an enourmous potential, but it comes down what you’re searching for if it works for you.


The Fluid* plugins on the MOD use the same base code that ardour does (ie, fluidsynth).
So we know it works.
What we need is a file uploader to put random files on the MOD.

No, pretty much all software is opensource (host, webserver, plugins), but the OS build system is not.
We make available the mod-plugin-builder, which is very similar and builds a base toolchain + libraries the same way the main OS does.
So you can use that to make binaries optimized for the Duo.