Beautiful Pieces of Outdated Technology
265fs Source of Uncertainty
In a frenzy of Buchla-DIY-kit collecting at some point in the mid-2010s, I had managed to acquire the front panel for a Buchla 265
but no circuit board or electronics to sit behind it. Therefore, after the nCoV-lockdown of 2020 allowing me to build the Buchla system
I had planned years before, I decided to layout my own PCB for the 265 panel I had. Upon searching for schematics and/or documentation, I
immediately found Non-Linear Circuits' "Sauce of Unce" design, which, whilst
function-identical, bypasses the need for expensive components and a +24V rail in a Buchla system just to produce some random voltages.
In laying out the NLC design against the Buchla panel, I realised I could add and adjust various things:
Like the majority of Buchla designs, there are also some caveats to all of this:
- 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.
Audio demos can be found here
- 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.
I am pleased to be able to offer both bare and semi-assembled, fully-tested circuit boards for this 265 revision! The semi-assembled boards 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. Boards will begin shipping by the end of
October 2020, with BoM and build information to follow in this time. Prices listed below are exclusive of VAT (added at checkout) and shipping costs can be selected via the drop-down menus.
Bare 265 PCB - £30 each
Semi-assembled 265 PCB - £200 each