The Synthrotek Verb is a lo-fi reverb module based on a trio of PT2399 delay chips set up as a resonator to simulate vintage reverb effects. One of its more unusual features is a voltage-controlled Mod parameter, which alters the tuning of the three delay lines. When tuned by hand, you can use it to dial in different resonant peaks and valleys to complement the sound being fed through it. When modulated, you get an interesting cross between chorus and reverb effects. In the following movie, I explore the Mod function, including using a spectrograph display to better understand its resonant behavior:

This is the second of two movies on the Synthrotek Verb from my course Learning Modular Synthesis: European Expansion. The first movie is a general overview of the module, including using an envelope and VCA to patch a noise gate for it to tame its more unruly behavior (which was baked in on purpose, following the classic Synthrotek ethos seen in their Dirt filter et al).