The ZiRCONiA is an optical compressor using a VTL5C3 vactrol (or similar), that includes a tilt style EQ, external EQ-bypass toggle, and internal Hi Cut switch. This compressor has a very smooth sound that doesn’t significantly color tone, while adding fullness and sustain. It is musical, easy to use, and can be left on all the time when set up for unity. There is also plenty of gain to boost a signal if desired, or if the compression level is raised while the volume is rolled back, it does a good job of sitting down & squashing notes too. Great compressor!
The ZiRCONiA Build Document includes BOM’s for both Guitar & Bass versions.
NEW DRILL TEMPLATE for V.1.1!! Please do not use the template from the older build document.
The older version of the ZiRCONiA had a handful of components in slightly different positions (R27 & R34, Q4, and C20 & C26). For those 5 parts, simply refer to the silkscreen on the pcb itself and you won’t go wrong.
For the older version of the pcb (if it doesn’t say V.1.1) use this drill template.