It’s a single transistor boost, not unlike an Electra. This pedal is somewhat infamous in the DIY community for exaggerated claims about what it sounds like – although no one in their right mind would question the quality of the point-to-point work in the enclosure that Rift did.
The Boost switch is normally a foot switch. Note that the gain control does nothing without the boost switch engaged.
RIFT AMPLIFICATION EL34 – VERO LAYOUT
SCHEMATIC & SPICE RESPONSE
It’s not much to look at – a bit of boost and dirt at higher settings, low-end is filtered off by the input cap and some highs are taken out with the tone control.
Schematic redrawn from the Gray Bench trace – check out the youtube channel if you have not already – a lot of good tear-down videos.
