Latest revision as of 13:47, 27 June 2026

A new modular approach, using Cornish granite, CNC cut copper circuit boards and a lot of magnets.

Theory and silly rules:

Trying to give a voice to 370 million year old electronic components - this is 'variscan coast' synthesis.
Changing/adjusting the crystal should have a clear result in most circumstances - they need to be in the centre of the circuit, so e.g. taking them away stops the sound for that signal path.
If possible circuits should highlight the differences between different minerals and source localities - these sounds have a kind of 'terroir'.
Specially made cat's whiskers mounted in Cornish granite to make the minerals the focus of a live performance.
Incorporate 1920s crystal wireless technology.
No tuning.

In practice:

Single sided PCBs glued to neodymium magnets, so they can be rearranged inside a repurposed tool box (protects them during travelling/storage). Modular without (so many) patch cables, structure follows flow.
Coping with components with wildly differing resistances, behaviours and other electrical characteristics means opening up control parameters much wider than when you tune them for a specific circuit or standardised ranges. This also means that for individual crystals a lot of the range of e.g. a potentiometer's range will not be useful.
Extensive use of vactrols (LED/light dependent resistor). This is to make circuits simpler and be able to see what's going on at the same time.
Sequencing via simple building blocks, binary counters and shift registers.
Syncs with analogue synths via pulse train.
Works well with volca modular, which has become a standard addition in live gigs.
Inputs/outputs are signal, +4.5V, 0V, -4.5V. Other voltage ranges also work (the diode ladder filter needs at least this much to work). Signal is replaced by clock on the sequencing modules.
It's designed to replace the log synth because I never wrote down the whole schematic, so I can't really build another one, it's not very portable and it's quite hard to swap out the voices, and e.g. the filters are hardwired to each voice. Many of the circuits are broadly based on what worked with that though.

Modules

(Photo credit Nik Nenov (cc-by-sa))

@@ Line 15: / Line 15: @@
 * Single sided PCBs glued to neodymium magnets, so they can be rearranged inside a repurposed tool box (protects them during travelling/storage). Modular without (so many) patch cables, structure follows flow.
+* Coping with components with wildly differing resistances, behaviours and other electrical characteristics means opening up control parameters much wider than when you tune them for a specific circuit or standardised ranges. This also means that for individual crystals a lot of the range of e.g. a potentiometer's range will not be useful.
 * Extensive use of vactrols (LED/light dependent resistor). This is to make circuits simpler and be able to see what's going on at the same time.
 * Sequencing via simple building blocks, binary counters and shift registers.