Korg Monotribe modifications thread

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nitro2k01
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Post by nitro2k01 » Thu Oct 11, 2018 9:10 pm

It's been such a loooong time since I posted in this thread, or logged into Muff's for that matter. (I'm soon having my 10th anniversary goo under my name, so that's cool.)

Anyway, I've finally started to get into what I wanted to do with the Monotribe from the start, firmware hacking. So, this is just a preliminary interest query. If there was a modded firmware, or one built from scratch, what kind of features would you be interested in?

A few possibilities:
Separate control of VCO/VCF frequency and intensity.
Simultaneous envelope and VCO
More complex LFO shapes or envelopes, such as full ADSR.
Tuned LFO settings.
A sequencer more targeted toward TB-303-like use.
Custom sync input and output formats, for example outputting a gate instead of a sync pulse or faster/slower sync PPM.
Or, even outputting a melodically tuned square wave on the sync output.

Would there be any interest in such developments?
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mckenic
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Post by mckenic » Thu Oct 11, 2018 9:46 pm

Ello!

ANY update to the sequencer would be wildly welcomed here!
Not a fan of the current set-up.

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Post by louis_srsmt » Tue Nov 13, 2018 3:22 pm

nitro2k01 wrote:It's been such a loooong time since I posted in this thread, or logged into Muff's for that matter. (I'm soon having my 10th anniversary goo under my name, so that's cool.)

Anyway, I've finally started to get into what I wanted to do with the Monotribe from the start, firmware hacking. So, this is just a preliminary interest query. If there was a modded firmware, or one built from scratch, what kind of features would you be interested in?

A few possibilities:
Separate control of VCO/VCF frequency and intensity.
Simultaneous envelope and VCO
More complex LFO shapes or envelopes, such as full ADSR.
Tuned LFO settings.
A sequencer more targeted toward TB-303-like use.
Custom sync input and output formats, for example outputting a gate instead of a sync pulse or faster/slower sync PPM.
Or, even outputting a melodically tuned square wave on the sync output.

Would there be any interest in such developments?
Hey ! Yes of course it would be awesome !! If you are looking for someone to test it, I can help, I had a few experiences in testing new synth and looking for limits or bug (with a friend who build synth)

I think the midi mode sold by amazing machine includes some CC's like cutoff, modulation, pitch bend, maybe you could look a it ;

for the features request, I don't think it's possible but if their is a way to store more pattern..that would change everything ;
and a portamento via pitch bend maybe ? That would be also tricky but awesome ; custom trig input is a fantastic idea as well

I deeply support your idea anyway, the monotribe is so awesome and under rated, once modded slighty and sequence externally it's a wonderful synth, the monotribe definitely deserves this :)

Cheers from France !

Louis

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Post by hamildad » Wed Nov 14, 2018 5:53 am

100 times a better ADSR for this thing...

but I dont think its possible to affect filter cut off, that's just not physically possible. its not possible with MIDI implementation certainly.

and I kind of like that you have to grab the knob to alter the filter...
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Post by nitro2k01 » Wed Nov 14, 2018 7:34 am

hamildad wrote:but I dont think its possible to affect filter cut off, that's just not physically possible. its not possible with MIDI implementation certainly.

and I kind of like that you have to grab the knob to alter the filter...
I will have to confirm this during the research, but my theory so far is that the knob and an analog output from the CPU are CV mixed. Ie, the LFO as we know it is 100% digital, at least we can control rate, intensity and target over MIDI. So a rewritten firmware could control filter CV, even if it couldn't disconnect the filter knob.
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Post by louis_srsmt » Wed Nov 14, 2018 8:49 am

I'm sure at 100% that the amazing machine midi kit implement midi CC for cutoff, but I don't know how they manage to do that

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Post by nitro2k01 » Wed Nov 14, 2018 9:19 am

louis_srsmt wrote:I'm sure at 100% that the amazing machine midi kit implement midi CC for cutoff, but I don't know how they manage to do that
The MIDI kit is "dumb". It just forwards the MIDI signal and does nothing else. Whatever effect the MIDI has is in Korg's firmware.
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Post by louis_srsmt » Wed Nov 14, 2018 9:29 am

Sorry I made a mistrake, I checked and hamildad was right, the cutoff can't be midi controlled ; my bad ;

here is the list of the midi instructions that can be read by the monotribe (according to the amazing machine owner manual) :

MIDI Note - ON / OFF
MIDI Velocity to VCA LEVEL (Needs MONOTRIBE OS 2.0)
Pitch Bend - Pitch Bend Wheel (-7 / +12 semitones)
LFO INT. - Modulation Wheel - CC 1
VCA LEVEL - Volume or Expression - CC 7 or CC 11 (Needs MONOTRIBE OS 2.0)
LFO RATE - General Purpose Controller 1 - CC 16
EG SHAPE - General Purpose Controller 5 - CC 80
LFO TARGET - General Purpose Controller 6 - CC 81
LFO MODE - General Purpose Controller 7 - CC 82
LFO WAVE - General Purpose Controller 8 - CC 83


Sorry again, hope that helps

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Post by hamildad » Wed Nov 14, 2018 11:57 am

nitro2k01 wrote:my theory so far is that the knob and an analog output from the CPU are CV mixed. Ie, the LFO as we know it is 100% digital, at least we can control rate, intensity and target over MIDI. So a rewritten firmware could control filter CV, even if it couldn't disconnect the filter knob.
Good thinking!!

you might lose the LFO though as you would reprogramme the digital LFO to act as a DC offset controlled by CC.

no problems as I never use LFO for OSC so making it a dedicated filter controller is fine for me... I do love the LFO though... you can use it to bring the OSC up past hearing frequency, then use the filter on external source only and LP out the high bandwidth OSC...

I would say if the firmware was stock BUT coujld decouple the OSC from the filter allowing you to use filter only, i'd snap that up. you can Mod it, but the guy who makes the nice Mods doesnt sell them anymore.
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Post by darenager » Sat Nov 17, 2018 4:18 pm

nitro2k01 wrote:It's been such a loooong time since I posted in this thread, or logged into Muff's for that matter. (I'm soon having my 10th anniversary goo under my name, so that's cool.)

Anyway, I've finally started to get into what I wanted to do with the Monotribe from the start, firmware hacking. So, this is just a preliminary interest query. If there was a modded firmware, or one built from scratch, what kind of features would you be interested in?

A few possibilities:
Separate control of VCO/VCF frequency and intensity.
Simultaneous envelope and VCO
More complex LFO shapes or envelopes, such as full ADSR.
Tuned LFO settings.
A sequencer more targeted toward TB-303-like use.
Custom sync input and output formats, for example outputting a gate instead of a sync pulse or faster/slower sync PPM.
Or, even outputting a melodically tuned square wave on the sync output.

Would there be any interest in such developments?
I’d be interested for sure, envelope and LFO hacks would be great, slides/accents, enhanced step lengths (currently for example you can’t have a say 15 step synth pattern, as it only allows 1-8 if 8 step mode, or 2,4,6,8,10,12,14 16 in 16 step mode) a realtime global step repeat which resumes where the pattern would be when released, step iterations only like play x out of x passes, etc. I’d be willing to pay/donate or whatever you have in mind, I believe there are around 20,000 or so Monotribe’s ‘in the wild’ based on the range of serial numbers I have in my collection of them, FWIW.

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Post by grenert » Sun Nov 18, 2018 3:29 pm

Hi, nitro2k01. My bias is toward enhancing the synthesizer. With MIDI IN, I don't bother trying to use the sequencer on board.

I would definitely be interested in a more complex or flexible envelope. LFO delay before kicking in would be cool. A second LFO and/or envelope would be awesome. Can you tell how much could be changed and still be handled by the hardware?

Best wishes on the project!

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Post by zaphod betamax » Tue Nov 27, 2018 3:37 pm

I have direct control over the cutoff frequency via a 1/8" jack wired to the cutoff pot.
So, CV is an option for controlling the cutoff of the Monotribe.

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Post by grenert » Tue Dec 25, 2018 10:23 am

I think the biggest limitation of the Monotribe is the lack of any envelope release stage. I was investigating disconnecting the software envelopes and adding in an analog envelope. However, I have learned that the oscillator tuning routines run when the gate is not on, so a hardware ADSR envelope is not an option. All the more reason for a firmware tinkerer to upgrade the software envelope! :party:

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Post by zaphod betamax » Tue Dec 25, 2018 7:45 pm

How about you run the Monotribe on perma gate closed mode in the setup,
So you send it V/octave CV for pitch and use an external ADSR (such as a Microbrute as the ADSR towards the filter using the external control of VCF mod.

I will fab this up and let you know if this works!

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Post by zaphod betamax » Tue Dec 25, 2018 8:25 pm

Yes the proof of concept works.

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Post by grenert » Sat Jan 05, 2019 12:55 pm

zaphod betamax wrote:Yes the proof of concept works.
Thank you for investigating, zaphod betamax! I have to admit I never even thought about controlling with CV/gate, since I don't have a modular setup. I've been using MIDI only so far, which doesn't give me the option of just leaving the gate open. I think I'll investigate putting a tiny ADSR board in there and locking the gate open.
Thanks again for the idea!

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Post by zaphod betamax » Sat Jan 05, 2019 2:17 pm

Funny, yesterday I watched this video:




Now I run OTB, however the concept in his video is
to disable the NOTE OFF.

I did the same OTB with Midi Solutions Event Processor
and it mitigates the click via Midi.

However, this turns it into a drone, and you will need some
way to attenuate when you do not want the note.


F0 00 00 50 29 01 00 00 02 00 7F 01 03 00 7F F7
80 00 00
{ Setting #1: Filter all Note-Off events on MIDI channel 1. Continue to process settings (right-click to edit) }

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Post by zaphod betamax » Fri Jan 18, 2019 11:40 am

With a simple mod of a 1/8" jack, 10k resistor wired to middle position of
Fc pot, you can run +5V CV control of the Fc.
Already have this mod of 5 out of the 6 Monotribes I have.

hamildad wrote:100 times a better ADSR for this thing...

but I dont think its possible to affect filter cut off, that's just not physically possible. its not possible with MIDI implementation certainly.

and I kind of like that you have to grab the knob to alter the filter...

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Post by XA101 » Sun Jan 20, 2019 7:29 pm

Man that polytribe sounds glorious! I forgot how much I like their sound, and it really works as a polysynth.

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Post by h4ndcrafted » Sun Mar 31, 2019 4:19 pm

Does the SyncKontrol app still work. Worked fine with my original unit, but can’t seem to get it to work with a new one.
Using iPad gen 5 , haven’t tried my iPhone Xr yet, need adapter.

Tried different volumes, polarities. If I turn the signal up super loud it just bleeds through, but lower volumes don’t do anything.
Any ideas :hmm:

Also what is the default state for polarity on the unit, step four light off ?

Sorry if this has been addressed, it’s a long thread now.
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MONOTRIBE ISSUES

Post by marcokava » Wed May 15, 2019 5:57 am

Hi All,
this is my first post, and i would like to share with you my mods on monotribe.
I would like to add:
add a CV control with arduino and capacitive shield [ done ]




ASend - Return for Wave only [ to do ]
Reduce clicks and pops

i follow this tutorial



But after reassembling all, i've a power on issues, to get on the unit i must keep pressed the power on switch, if i release it the unit go off..
Any one have some suggestions?
Thanx
M.

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Post by darmklacht@gmail.com » Wed May 15, 2019 8:45 am

I wish I could mod my Monotribe to be a self cloning device...

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Post by quartzite » Thu May 30, 2019 10:44 am

I'm about to be a proud owner of a monotribe! Does anyone know how to mod the BD/SD for tuning? The only evidence I've found so far is this video demoing it briefly .

EDIT: found some info from remork on page 38, also the video creator added some info to his vid

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monotribe

Post by midirobot » Tue Jul 09, 2019 4:39 am

great thread ! thanks guys : )

just get a monotribe already made cv/gate input mod to get rid of the trrs cable,and add cv input to filter cutoff that little box is really great already !!

now i 'd add trigger input on the drum part somebody manage it can't find info ?? really would like to use mutable grids with those modded drums !

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Post by zaphod betamax » Sun Aug 04, 2019 11:30 am

I have modded 5 out of my 6 Monotribes for cuttoff control via CV.
It is an analog control of a pot that is intercepted and jacked out
at the wiper of the cutoff pot.


nitro2k01 wrote:
hamildad wrote:but I dont think its possible to affect filter cut off, that's just not physically possible. its not possible with MIDI implementation certainly.

and I kind of like that you have to grab the knob to alter the filter...
I will have to confirm this during the research, but my theory so far is that the knob and an analog output from the CPU are CV mixed. Ie, the LFO as we know it is 100% digital, at least we can control rate, intensity and target over MIDI. So a rewritten firmware could control filter CV, even if it couldn't disconnect the filter knob.

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