Zeitgeist is an open source delay effect/sound source based around heavy abuse of a PT2399 karaoke delay chip devised by Rob Hordijk. The four knob controls are as follows:
- INPUT – sets the input signal amplitude
- MIX – This is a combination Wet/Dry and Feedback control. All the way to the left, you have only dry signal. As you turn this control up, Wet signal is added to the mix, and more signal is fed back through the delay simultaneously.
- TIME – This is the control for the delay time. Turn this knob to the right to increase delay time.
- MOD – This control allows you to inject CV and LDR signal into the TIME parameter. All the way to the left and CV will have no effect on the timebase.
Additionally, this pedal has 2 switch controls
- Above INPUT you have a boost/cut switch. The +3db/-3db boost and cut affects both the input signal and the feedback signal.
- Above MOD you have the LDR control switch. In the middle the LDR is removed from the circuit. In the left and right position you can change whether the LDR has a positive impact on the timebase, or a negative one.
Zeitgeist also features an expression control input and Banana CV input and Banana Ground. Zeitgeist has true bypass and runs on a 9V centre negative supply. Any supply between 7V and 12V will work, and this unit has reverse polarity protection to prevent unhappy accidents. The pedal consumes 20mA at 9V.
Note: Zeitgeist has a 10K input impedance, which makes it unsuitable for direct guitar input (you’ll need a buffer/preamp of some kind). It has a 1K output impedance.