Univibing the Electro-Harmonix Small-Stone (’97)

Sometime in the late 70’s Rick Onslow – Frank Marino’s tech at the time – said to me that you could modify pretty much any four stage phase-shifter to make it sound somewhat like a Univibe … the key word here is “somewhat” for I haven’t set them to lie exactly where a Vibe has them set, rather I’m playing with the 10:1 decade ratio in two parts … I decided to first try this idea out that concept on the Small-Stone OTA-based circuitry though I’ve more recently done it on Op-amp based circuits, and those are matched to the Vibe response … recall that well-behaved “studio” phase shifters have their all-pass filter stages set to an identical shift frequency by using the same shifter cap value throughout …

via Univibing the Electro-Harmonix Small-Stone (’97).