Demonstration of Monotribe VCO2 mods

Demonstration of the following Monotribe modifications:
2nd VCO in LFO mode controlling VCA
2nd VCO tracking ~4 octaves of VCO1 CV
2nd VCO soft/hard syncing with VCO1

[@Cloroqx]

Beautiful work, mate. Can't wait to see this thing finished.

[@mCKENIC]

Amp mod and soft sync really sound like they will make the 'Tribe a whole new synth! Cant wait to see where this goes but I really did like the bloopy sound with the breadboard 'mistake' :-)

[@mark_madel]

Thanks! I'll post schematics once I get the boards designed!

[@HenkFueltank]

Great stuff, this is a great addition to the monotribe. I hope you'll be able to sell the SMD boards premounted, since my soldering skills are non existent

[@jazzzAiman]

Amazing, I still find monotribe being a very fun synth. though 5 years since you touched it, wonder if you could share a schematic for ins/outs for the vco2

[@mark_madel]

Hey Andrej - Believe it or not, this Monotribe project (which was a paid project from a client) got delayed. So right now, 5 years later, I'm actually finally assembling & testing the first boards for the Monotribe MadMods - a modular system for the Monotribe which adds VCO2/PWM/RHYTHM/CV OUT/GATE OUT and much more (all of it inside the case). Within a month or so, I'll post a video demonstration, and the boards will be available for people to purchase cheaply - and you can add all of it or just pieces (modularly) to your Monotribe over time. Here's a photo of the 5 boards that fit inside the case: markmadel.com/da/share/monoboards.jpg

[@jazzzAiman]

​@@mark_madelnokiddin, boards look beautiful, sign me up the waiting list. you know what, forget the waiting list, I want this right now :D

[@locussst]

@@mark_madel any word on this?

[@mark_madel]

@@locussst Hey Jimmy - I've already built the boards, drilled the case, and assembled everything (and shot video of the assembly) - just working out one last bug in the VCO2 tracking, and then I'll make the new labels for the case and shoot video of the Mad Monotribe in operation. So I'm close to posting video - hopefully within the next 10 days.

[@mark_madel]

​@@locussst - Posting a bunch of videos about the finished mad.monotribe today. I'll be having some Rev. 1.1 boards made in August (w/a couple of added features, such as VCF Cutoff CV IN / 0-5V), so if you have any interest in any/all of the boards - and if you'd prefer to get them populated or bare - leave a comment or DM me. No obligation, of course; I have to build two more for a client, but I'm trying to gauge people's interest before ordering boards.

[@Drageslukeren]

Just to add CV to the amp, where would that be connected, resistor to base where you added the click capacitor? Was thinking just to add the stock LFO to amp with a switch for instance, or patch over LFO from monotron as I assume CV levels would match. And how about taking that envelope to amp to the filter, will splitting it be to much drain?

[@mark_madel]

Sorry I'm slow responding, but I'm travelling at the moment so I'm not around my schematics (or mods). But I'll try to answer your questions the best I can without the data in front of me. 1) No, you shouldn't try to inject CV to the VCA near the differential amp. It's much better to sum it with the EG CV near the integrator op amp (IC17). I think in my mod I used another op amp for summing, but I don't remember at the moment. 2) CV levels are different between the Monotron and Monotribe because CVs are generated via PWM by the Monotribe's CPU and then low pass filtered with integrators. They need to be up or downscaled when going/coming from elsewhere. 3) Yes, you can use the EG CV elsewhere, but you may have to scale the levels (the EG CV is 0 - 3.3V). You should tap the voltage off at IC17 pin 8 (the output of the PWM integrator).

[@steadthomas4552]

So, say I want to have a 0-10v env drive the monotribe VCA (and maybe VCF). Would I want to make a circuit to scale the incoming envelope down to 0-3.3v then tap in before r202, right after the PWM eg filter? Would it mess anything up if I used a switching jack to cut off the internal eg? Thank you so much for doing this work and for sharing!

[@mark_madel]

Stead Thomas Hey Thomas - I missed your comment when you first posted it, so you might have figured this stuff out already, but if not, I'll answer your questions. In my mod, yes, I put a SPDT switch before R202 that selects between PWM eg and the 2nd VCO as control for the VCA (although a switching jack would work fine). The voltage level is lower than I wrote above since the integrator levels out the PWM voltage (when I answered Drageslukeren I was in the USA away from my studio, so was just looking at the Korg schematic input figure and not the measured output). The output of IC17 pin 8 is 0 - 2V, so that is what you should scale your 0 - 10V to.

[@alien_brain]

are there any more of these available? i want one!

[@mark_madel]

@alien brain - I realize your posted comment is from >4 years ago, but perhaps this is still of interest to you. The Monotribe modding job I was breadboarding/designing for a client 6 years ago got shelved for 5.5 years - but was restarted this January and is now finished. So I'm posting a bunch of videos about the finished "mad.monotribe" today. I'll be having some Rev. 1.1 boards made in August (w/a couple of added features, such as VCF Cutoff CV IN / 0-5V), so if you have any interest in any/all of the boards - and if you'd prefer to get them populated or bare - leave a comment or DM me. No obligation, of course; I have to build two more for a client, but I'm trying to gauge if there is interest before ordering boards.

[@alien_brain]

@@mark_madel its long gone but thanks

[@jounihelminen6025]

any news on the board? would love to buy one

[@mark_madel]

Sorry, I've been swamped with other work which paused the Monotribe mods. But I hope to get back to it within a couple of weeks and will send you a PM when they're done.

[@austinbru]

HI Mark, I know this is a very stale video. But I would be very interested in any Monotribe mods that you offer - given your experience in music electronics.

[@mark_madel]

+Austin Brubaker - Hi Austin - Sorry for the slow response; it's been hectic. I'm hoping to get a new batch of Monotribe Mod boards made within the next 6 or 7 weeks, and I should have a few to spare. I don't currently know what I can offer them at (assembled or un-assembled) but it shouldn't be too much, since the batch has partially been paid for already. I'll get back to you when they're done.

[@austinbru]

Many thanks to you, Mark! I appreciate you getting back to me when you are so busy - I can empathize with you on that one no doubt (this message just caught me on an alert and semi-relaxing day, hah). I am neutral on the assembled vs un-assembled bit (assuming they aren't terribly difficult to solder). I am not sure how to PM you on KZbin, but let me know if you would like my contact info to continue the discussion! Thanks again.

[@mark_madel]

@ jouni helminen - I realize your posted comment is from >5 years ago, but perhaps this is still of interest to you. The Monotribe modding job I was breadboarding/designing for a client 6 years ago got shelved for 5.5 years - but was restarted this January and is now complete. So I'm posting a bunch of videos about the finished "mad.monotribe" today. I'll be having some Rev. 1.1 boards made in August (w/a couple of added features, such as VCF Cutoff CV IN / 0-5V), so if you have any interest in any/all of the boards - and if you'd prefer to get them populated or bare - leave a comment or DM me. No obligation, of course; I have to build two more for a client, but I'm trying to gauge if there is interest before ordering boards.