The Ceres Preamp Drive is an adaptation of the Catalinbread Sabbra Cadabra, their take on Tony Iommi’s signature tone achieved by putting a Rangemaster-style treble booster in front of a Laney Supergroup amplifier. It was originally released in late 2014.
The Sabbra Cadabra’s control set is simple, with controls for pregain (attenuation going into the Rangemaster stage), gain (attentuation after the first amplifier stage), presence (hi-cut near the end of the circuit), and master volume.
Like several other Catalinbread pedals, this circuit blurs the line between a preamp and an overdrive. Like a true preamplifier, it’s very reactive to what comes before it, so it’s best placed after other drive pedals but before modulation. However, it also generates more than enough drive on its own and can be used as a standalone overdrive pedal just like any other.
The original Sabbra Cadabra used MPF4393 JFETs, which are no longer produced. Aion FX sells the original MPF4393 in sets of 5. The PCB also has an extra pad so that surface-mount JFETs can be used (part number MMBF4393), which are still in production and perform identically to those used in Catalinbread pedals. See build notes for more details.
The Ceres is compatible with the 18V Voltage Doubler / Bypass module if you want to run the circuit at 18V without an external adapter. The higher voltage provides increased volume and clarity.