Brenn - Quad slow LFO

Having been in the community for a few weeks now, lurking for a while before that, and developing a few Kosmo format modules I have decided now is the time for me to start sharing.

I have a few modules on my github that I shall announce over the coming days and should be on Kosmo modular grid soon.

My first module is a Quad Slow LFO, in a 100mm module.

  • 4 Lfo’s
  • Each has a cycle duration between a few seconds and a few minutes, approx 6 sec 12 minutes
  • Each LFO has its own speed control
  • A single global speed control
  • CV control for the global speed (not 1V/Oct)
  • Each LFO has both unipolar and bipolar outputs

I have been using the lfo for slow evolving movement of sounds, it is not a replacement for a standard lfo, normal tremolo and vibrato can not be realized with this module.

It is based on the Single-cell VCO on the LM13700 datasheet, this is a triangle wave with a big step so I added an LPF to each oscillator.

Contained are schematics & Gerber files for pcb fabrication of both electrical and front panel. This is suitable for entry-level however a basic level of electronics, soldering, fault finding, and some basic tools are required.

You will see the 6 + 1 logo in places, however, I am moving away from this imaginary brand name as I used it on a previous opensource project that I have currently put up for adoption, I have decided I’m too old to use a pseudonym and an now just going to use my name. I due course I shall be removing the old logo and not replacing it, however as I wont publish anything I have not built and tested you will see my old logo until I need to get more panels fabricated.

As with all my projects constructive criticism is welcome, all I ask is it is kept public so all the community can benefit.



Nice! I too used one of the lm13700 datasheet triangle oscillator in my LFO, but not this version with the back to back diodes.

Personal preference, but I consider an unused op-amp a sin. Maybe there is something interesting to be done with it? Maybe summing a quarter of all separate LFOs to make a funky waveform? Or a Schmitt trigger to provide a square wave LFO from one of the others. Or maybe something else as yet unthought of…



Or just add some buffered LEDs…