1007 MIDIMUSO MIDI - CV
This is July’s Offering of the Kosmo Module a month project.
Its a multi function MIDI - CV module that is based around the CV12 chip made by midimuso
This module all in all has 12 CV outputs and 6 Trigger outputs. 2 MIDI THRU’s and also a MIDI SIGNAL LED
There has been some changes to the Midimuso code, for instance the action at which is works is return to bass, Also 0v is C
The CV12 has a massive amount of flexibility, you can have it as an extencive 1 channel midi to cv device, a 4 voice polyphonic midi-cv even a 6 channel midi to cv device
Not to mention the fact it can be chained together to expand even more!
CHECK THIS FORUM PAGE ON PEOPLE BUILDING IT LOOK MUM NO COMPUTER FORUM
most of the functions of this module are the same as the CV12 and information can be found HERE
THE MIDIMUSO MANUAL CAN BE FOUND HERE
I definitely recommend becoming acquainted with the information on the above linked page
As this module is basically a modular friendly version.
The front panel of the modular version labels the functions of the module in the 4 Channel MONO Mode, which the chip that comes with the module comes with that mode as default. HOWEVER, i will be also offering in a few weeks blank unlabelled panels to get hold of if you want to label your module panel for another one of the modes which you prefer (all you’d need is a silver sharpie).
CHANGES TO THE FUNCTION OF THE STANDARD MIDIMUSO/EXTRA PROGRAM CHANGE MODES
In order to change the modes on the midimuso it involves midi program changes, you send in program change 99 then the designated program change for the function you want to change, it is documented in the midimuso manual here. however to make things easy! Midimuso has included a folder of files that you play through any midi interface which does the changes for you the file can be found here. Either drag the file onto something like logic and play it through a midi interface or even a usb midi keyboard that has a midi out into the midi - cv module and you will have succesfully changed modes!!
Below are extra modes and changes added to the KOSMO version of midimuso, as it runs on return to bass mode aswell as retrigger mode from default.
Modes to enable / disable RTB or Retrig
Program change 99 followed by:
100 = Retrigger off
101 = Retrigger on
102 = Return To Bass (RTB) off
103 = Return To Bass (RTB) on
127 = PANIC! (Gives 3 short pulses on all pins on Port D and resets)
join the conversation over on the forum! there will no doubt be alternative BOM’s coinciding to where you live! FORUM PAGE HERE
Image of everything going into the Circuit board
Image of everything going into the Jack Board
BATCH 1, Just a quick one regarding batch one, there are no mistakes however the IC designation of MC14504 correlates to the TI4504’s which are included with the PCB/PANEL/CHIPSET in theory the MC14504’s will work in place however after speaking to Robert over at MIDIMUSO, It would seem they are not as good as TI4504’s, I have some MI14504’s on the way to see how they act. But yes! hopefully that clears that slight confusion up.
ALSO ON BATCH 1, the front panel has a small number code on it on the first batch which will not be there on subsequent batches, on the next batch i will also be offering a more Blank board so you can label the outputs for the mode you like the most! however if you got a panel from batch one and want one without the code, fire me an email in a few weeks and we can figure something out!
The Circuit
The circuit is largely the same as the CV12 one that can be found on the midimuso site here, with a handful of differences that suit it more for modular use.
A MAssive shoutout to fredrik and antoine alary who helped us figure a few things, most namely the power reference. The midimuso uses an LM317 LDO however its voltage drop made it nearly impossible to reach the 10.6v with any reliability on modular power supplies, this opted for a change of tact to using a TL431, THE CONVERSTATION ON THIS POINT CAN BE FOUND HERE. This solution results in a nice stable supply. The optimum voltage is 10.67 however anything between 10.6 and 10.7 does the job on the voltage reference. As it correlates to 10 full octaves of 1v/oct. Needless to say!!! you can actually adjust this voltage reference to run on other CV references. 1v/oct being the most common, especially in the KOSMO format.
The power input is just your common powering situation on all kosmo modules. keeping it nice and simple. there are options of adding more power protection! i will touch on that very soon.
The pitch bend has its own reference offset, this means you can set its centre point to 0v. How to achieve this is by either using a multimeter and measiruing the voltage coming out of the pitch bend jack, and getting it to 0! ORRR you could just plug it into a oscillator and keep twisting the trimpot till you cant notice a difference between the jack plugged into pitch bend or not plugged into pitch bend, this means that its calibrated to 0v!
to make the most of the pitch bend plug this into a cv input of an oscillator and you can adjust the pitch bend range with the cv input attenuator on the oscillator.