Congrats @falkTX on getting CV done!
I’m going to try ASAP seeing @unbracketed comment on noise. I’ve stopped using mine as the processing noise was so bad. Fingers crossed this fixes it!!
Steve
Sadly CV is one of the most variable ‘standards’. While you’re waiting the official response you might like to read this - https://en.wikipedia.org/wiki/CV/gate
There is some info on https://wiki.moddevices.com/wiki/CV_Tutorial
On the current units, you can send 5v to the inputs. The headphone jack can act as cv out, but it is set as headphone mode by default (it is a switch on the device menus)
Expression pedal mode is a switch on the inputs.
It makes one of the CV inputs actually output 5v.
This is to that it can drive, well, expression pedals.
The “CV meter” plugin is very useful to ensure things are working correctly.
1 Like
What’s a NAND unit?
Steve, have you got the K-Mix and the Duo plugged into the same computer? If I do that, to edit patches, I get hella noise. But if I either unplug the Duo (or X) from the laptop, or plug into a different laptop, I’m fine - there’s a ground loop thing happening between the USB sockets…
1 Like
Hey thanks Steve. No it’s just the Duo X into my PJB bass amp and noise is same with or without USB pluged to computer.
Thanks for the suggestion tho’. I’ll watch out for that.
NAND refers to the type of flash memory used, like for those in a usb stick.
On newer Duo models we changed from NAND to MMC, as the latter is much more reliable.
We have a way now to make the older units flash memory much more stable, leveraging some tricks that a new linux kernel allows (it was simply not possible/available back when we first started development on the Duo).
So going forward, we want to have the older units using the new kernel and drivers. As file handling is coming in a later update in the year, it is crucial that access to files is as stable as possible (even more than before)
We will have a lengthy forum post about this closer to release.
7 Likes
how do I know if my unit is NAND or MMC? (I can do ssh if needed)
I started getting some issues after restarting after the upgrade.
Did $SOUNDCARD changed?
I saw that systemd startud hanged on mixserver.service and after digging a bit into it I realized that it was failing to access the soundcard,
/usr/share/mixserver/mixserver.py:30 printed “Can’t open ALSA control device.” (It’s pretty cool to be able to look at this 
)
The env variable was not set on my shell, but on the script it defaulted to MODDUOX, which won’t work
as aplay -l only lists DUOX. After setting it on the systemd unit I was able to get past it,
[Service]
…
Environment=“SOUNDCARD=DUOX”
mount -o remount,rw /dev/mmcblk0p2 /
cp /etc/systemd/system/mixserver.service{,.bak}
vi /etc/systemd/system/mixserver.service # Add that Environment line
systemctl daemon-reload
systemctl stop mixserver
systemctl start mixserver
mount -o remount,ro /dev/mmcblk0p2 /
I think that this name just changed unintendedly as many other
things just refer to MODDUOX, like the webserver which I figured after finding a bug in the
UI as some request to set up some knobs was failing.
My screens are also not working 
. I guess I can try and add that environment variable
everywhere just in case (or figure out how to rename the soundcard?).
I haven’t tried re-imaging again yet, but I’ll guess I’ll just go that route tomorrow.
The mixserver service is not supposed to be started unless you specifically enabled it in the web gui advanced settings.
The top of the service file has this:
ConditionPathExists=/data/enable-mixserver
In any case, this is a legacy service we do not use anymore, we just keep forgetting to remove it.
So we will do that now.
It is not that things got renamed, we just never bothered to fix that service because it is off by default and simply unused at the moment.
Oh, I didn’t meant that the service got renamed, but the sound card
I know, I understood that. The bad name comes probably from initial testing of ours trying to make that service work for Duo X, and then just leaving it behind.
1 Like
I just flashed the new modduox-v1.9.0.1220.tar into my ModDuoX and the screens are still stuck with the [MOD DUO | X] logos and I can’t assign knobs on the web UI.
The restore was successful as I recovered the broken behaviour of the mixserver unit (the service doesn’t matter, but it confirms I’m running the new image). I’ll give it another try, but not for too long as I really wanted to practice some songs, so I’ll revert to v1.8 if I don’t get any leads.
How do I know if my unit is NAND or MMC? What do I need to check?
1 Like
Is the dedicated telease for the Duo coming soon?
I’d like to have the midi number indication and other interface enhancements.
1 Like
That is really unexpected.
What pedalboard do you have it booting by default?
Can you try booting with nothing connected to the autio inputs please? Thanks, and sorry for the trouble
The outer case of the unit is a bit different, new units have MOD DUO label on the top right.
Basically:
Left one is NAND, right one is MMC
We hope to have a public RC out in a few weeks.
3 Likes
Great, thanks for the info. We appreciate what you have done for the Mod Device community.
2 Likes