Deluxe Tremolo

 Earlier this summer I learned about the existence of a thing called 'Harmonic Tremolo'.
Apparently the effect has been around for ages, but somehow I totally missed it. You can find the effect on Fender amps from the early sixties.

I chose my standard Tremolo as a platform to experiment with, so I hooked it up to my breadboard and started adding various components in different places of the circuit and compared it to examples found on YouTube. My breadboard experiments didn't really nail the harmonic tremolo sound I heard on the video's, but instead of trying to get closer to existing circuits I decided to shut myself off from outside information, and just tune and adjust my breadboard pedal by ear until I found sounds I liked, and then write down the values I used.
I initially wanted to use a potentiometer that allowed you to select different effects and everything in between, but I settled on four preset sounds using a 4-way rotary switch.
The settings are;
1- Tremolo
2- Tremolo with frequency modulation
3- Frequency modulation
4- Pitch vibrato

The Deluxe Tremolo with added components in place.

To my surprise I only needed 2 additional components for each setting to get these sounds and realized it might be possible to fit all this within the existing enclosure with the addition of just one extra knob.

The 'standard' Tremolo that served as a platform for these experiments.

The production model will have a chicken-head knob in the middle for easier switching. It got in the way of the other knobs on this prototype as I miscalculated the distance needed between knobs.

Here is the demo video;