This is a PCB for the Buchla 265fs Source of Uncertainty module.

The electronic design is based upon the Non-Linear Circuits Sauce of Unce module. 

The bare boards require soldering of 0805 passive components, SOT-23 discretes and SOIC ICs. The semi-assembled boards (which are available direct from Finlay) come with all surface-mount electronics fitted and fully tested. These boards only require jacks + LEDs + a power connector + a panel + knobs + mounting hardware in order to be turned into a fully working module.

£5 of each sale is sent to Andrew at NLC as a royalty. The Bill of Materials can be found here.

In laying out the NLC design against the Buchla panel, Finlay realised that he could add and adjust various things:

  • There are two separate noise cores, giving uncorrelated low / flat / high noise pairs at the TinyJax outputs. This allows for true stereo noise.
  • Each Smooth and Stored section features a trigger output, which fires when the random voltage goes above 5V (theoretically 50% of range, though the gain is somewhat difficult to set precisely due to it being a random module). These trigger outputs are proper Buchla triggers, with the gate portion of the trigger going low when the voltage has descended below 5V.
  • The LEDs show both the continuous CV output as well as the trigger state via the use of bipolar LEDs. This results in a pretty psychedelic look (woah man radical).
  • The noise cores can be jumpered to refer to either Q or N grounds. The LEDs all refer to N ground, as per the Buchla “standard”.
  • Signal levels have been set for line level audio and 0-10V CV ranges from the Buchla +/-15V supply. However, the noise level is trim-able so can boost levels down the chain.

Like the majority of Buchla designs, there are also some caveats to all of this:

  • The noise cores are pretty susceptible to clock noise. Examples of this are provided in the audio demos below, in what I believe to be the worst-case scenarios. From reading Dave Brown’s info on the 265, this seems to have been a “problem” with the original module, and from speaking to Andrew at NLC, it’s also present in the Sauce of Unce design. However, if clean noise is desired, the clocks can be slowed all the way down to near-off – this is also present in the demos. Also, the clock bleed becomes far less noticeable once the noise sources are filtered and/or gated.
  • Due to the nature of the Smooth section, it is possible for the outputs of these sections to go ever so slightly negative. This isn’t a problem for my system, which is fully analogue, but digital users beware.

Audio demos can be found here

Bill of materials is provided here

Boards can be purchased here, and front panels can be purchased here.  PCBs or part assembled units can also be purchased direct from Finaly here.

Front side of PCB –


Rear side of PCB –


Example of populated PCB –


Example of completed build –


Example of compatible panels –


Notes –

  • PCBs are supplied bare (components must be sourced)
  • No warranty is given nor implied