Posted: Sun Aug 24, 2025 3:05 am Post subject:
8 CV to MIDI converters Subject description: CV Option / expander module
Hello everyone,
I developed a module to expand my 8 channel CV2MIDI - Converter in direction towards a kind of real fun "Modular Sequencer":
It consists of 8 independent channels controlled by 8 "control cells" on the right side.
The module is pure analog with 4 PCBs hosting 2 channels each:
(Above: Please note my "sustainable" (to abuse the bad word of this decade) PCB approach by using very old and used vintage resistors with clear-text resistor values coming from the pre-color-code and pre-pcb times (in fact they propably served in Adolf's table-top radios during the "Third Reich" 😂😂😂) and found their way to me when I bought an electronic convolute from the heritage of a dead electronic nerd on ebay...)
Anyway, this module offers a variety of new sequencer modes when used in conjunction with my 8 channel CV2MIDI Converter:
The module provides 8 CV sources and 8 clock sources (CLK), which are adjusted by corresponding control pots.
The clock behavior is controlled by cells on the right module side.
Witch each controller cell you set the clock operation for the corresponding channel / step.
Switching it to "ON" means a permanent 5V output at the clock output jack.
Switching to "CLK" means a normal clock operation.
Both are indicated with corresponding LEDs.
For working with the CVOption module a new program was developed for the CV2MIDI converter (Program 5).
This program interprets a 5V input at a clock jack as "lock", where the sequence executed by the CV2MIDI converter changes the sequence direction, so you can define a new sequence length.
But if you define the lock as CLOCK based the sequence cursor sometimes returns at the lock position, and sometimes not. The sequence gets a randomized length.
The situation becomes really weird if you define 2 CLK locks at different positions in the sequence with different speed rates.
Then the sequence cursor is caught in different parts of the sequence at different times like a lost ping-pong ball jumping to random segments.
Above: PCBurger and Pasta 🍔🍝
Above: As purely analog, channel CV adjustments on the back side
The Circuit
Above: Schema of a single channel
Each PCB (2 channels) has its own PSU adaptor, as the LEDs consume a lot of current.
Both front panel pots are 1k.
The CV unit (U2) operates from exactly 0V to 5V adjusted with the OFFSET and AMPLITUDE trims.
The LFO (A5) operates from 1Hz to the lower audio range.
The clock operation selection logic (Q1, Q4) is controlled by the front panel switch (J5). The clock output modes are set to 0V and 5V and provided at the output via the discrete "OR" logic of Q2 and Q3.
That's a very impressive (& professional) build you've done there.
I also like the use of the old resistors with the value printed on them rather than those modern five-band ones with indecipherable colours !
That's a very impressive (& professional) build you've done there.
I also like the use of the old resistors with the value printed on them rather than those modern five-band ones with indecipherable colours !
Andy
Thanks 😊
I must admit that I've never seen such resistors before 😮🤔
Here the next level: I added ratcheting as new program to the CV2MIDI converter:
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You can download files in this forum
Forum index » DIY Hardware and Software
FAQ
Calendar
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
Chat Room
