Duo X channel 1 bleeds to channel 2

I was playing together with my girlfriend, she on guitar (1) and me on bass (2), each on our own input channel.

Then I added a big-muff to the bass chain and lo and behold -> it appears that the guitar is coming in on the input. Quite loud even :o

It is not as loud as on input 1, but I can clearly see from the LED next to the input that it’s receiving a signal. Bypass still works, so it must be after the relay.

Is this something faulty with my unit? is it the ADC? a software issue?
This kind of cross-bleed should not happen, right?

Initially I was testing a v1.10 build, but it also occurs on v1.9


Of course had to test the other way around, exactly the same result (softer and muffled compared to direct input, but very present signal bleed)

Hey @dreamer, that may be an annoying issue especially for the use case that you were trying top get done.
I would suggest you to get in touch on support@moddevices.com

Well this breaks the whole “2 separate processing chains” entirely, so it’s more than annoying imo.
Will write up an email to support on this.

Still wondering if I’m the only one experiencing this or if it’s a limitation of the design.


Only today found Mod Duo X input Bleed which describes the same issue I believe.
No reply from support yet :slight_smile:


You will get one, I assure you :wink:

Need to know if this is gonna be an issue on similar (same?) hardware in terms of inputs on the Dwarf. Nobody here has had to get answers on it previously?

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The Dwarf is an entirely new/different hardware design from the DuoX. Even a big part of the software has huge differences between both devices.
Besides that, as you probably know, we are running a beta test with the Dwarf what will help us pinpointing and fixing these types of issues at an early stage and hopefully not have them when the Dwarf production is in full steam.
Until now, I can tell you that there were no reports of this issue on the Dwarfs that we shipped.

I can confirm this on my Dwarf. I have tested this with my synthesizers today (on line level) and it works with no bleeding at all between the two seperate processing chains. :upside_down_face:

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Did anything ever happen with is? I see exactly the same thing using my Chapman Stick (a stereo stringed instrument).

An odd thing I notice is that the ‘bleed’ seems to be quite short lived, i.e. if I play a note on that should only be channel 1 it appears in both, however while the note sustains as it should in channel 1, the channel 2 bleed fades quite quickly.

N.B. I’m not complaining about the ‘fade’ (I don’t want it on Ch2 at all!), just adding an observation in case it might be useful.

MOD DUO-X fully patched for latest update.

Some sort of response would be appreciated, even if it’s just “We can’t reproduce the issue”. :slight_smile:

Correction. I see see bleed from Ch2 to Ch1, so reverse my comments above.

Extra info. On my pedalboard (on which ‘1’ & ‘2’ are entirely separate) I have a the ‘C* Click - Metronome’. That’s outputs to Ch2, but there is no bleed of the ‘click’ even when it’s at a similar volume to played notes. Perhaps that indicates that the issue is on the input side, i.e. before the signal enters the pedalboard section of the signal chain?

I hope that helps.

Can’t this be related with your gain setting for both inputs?
Please send an email to support@moddevices.com with the issue. Add the device serial number and if you can a video showing the issue.

I thought it was already confirmed this was an issue with the design of the DuoX, have now read several confirmations about the signal bleed between input channels. This certainly is not a software problem.

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In System both inputs were set to -4.00 dB. I’ve changed that to 0.00dB. The effect still exists, but maybe a little less? The inputs are from single coil passive string pickups; what would you suggest as suitable levels?

I notice that https://wiki.moddevices.com/wiki/Device_Settings#MOD_DUO_X describes the default Profile settings in terms of % rather than dB. That discrepancy in terminology does not seem helpful (or am I looking in the wrong place and comparing different things?).

Studying further I noticed that the effect seems to be more significant at some frequencies; most noticeable at very high (high guitar string) or very low (low bass string). Some crosstalk on the instrument pickups is not unimaginable. The low bass string is substantial and is the one that is closest to the melody (guitar) pickups. It seems less likely that the very insubstantial high guitar string, the one that’s furthest from the bass pickups, would register significantly on bass pickups and yet it’s the string that gives the greatest effect. Muting the opposite set of string slightly reduces the effect, but only slightly, so I don’t think that sympathetic vibration is significant.

However, having gone through those thoughts I tried plugging direct into my mixer. Result, I see an effect there too! That’s strange as I’m sure I tried that a few days ago & didn’t see any bleed! However, given what I’ve just seen I have to assume that based on current evidence the MOD Duo-X may be the innocent victim of an external effect?

I’ll ask around in the Stick community to see if anyone can cast further light on this. If that ends up revealing something that looks to be MOD Duo-X specific I’ll report again.

Thanks for your time.

PS. Your view(s) on my question about suitable input dB values in System would still be appreciated.

This is some outdated information. We changed the way that it shows with the 1.11 and that went missing. We will fix it asap.

Sorry to intrude, but I have to mention that in the case of chapman stick - there is always some bleed between pickups on the Stick itself, pickups are mounted on the same device after all. Usually it is refered as a pickup cross-talk, I recall even Greg (Howard) to mention it in one of his videos. It is usually subtile, but it always exists. I even see people discussing using pass filters to deal with crosstalk - Stickist.com - View topic - Distortion

I was able to hear this cross talk on my Railboard in setups that do not include mod device or even a stereo connection - for example by connecting only melody output to my audio card and tapping lowest bass string quite hard. In this case I hear some kind of a weak echo of the bass string harmonics.

Not trying to say that you do not have input bleed, however, I will try to test it on my ModDuoX.

After some testing. Luckily I have not noticed any signs of the input bleed on my MDX.


Not an intrusion. Insight into the experience of others is always useful. Thank you. As you may have seen in posts later than the one you quoted, I’d already come to the conclusion that the MOD DuoX is innocent here. I see crosstalk even if plugging directly into my mixer. This is an old (1985) Stick with Stickups. There’s a topic on Stickist about my efforts to set it up, including solving the issue that when I first got it was giving mono output (It turned out to have been rewired inside the pickup block as mono by some former owner!).