Reverb - Analog* Reverb Pedal
REVERB is an all-analog circuit implementing four separate PT2399 delay lines, each spaced 1.5x apart in time, insuring minimal overlap. This design targets a generic, natural resonant echo-chamber effect, as opposed to aiming to mimic a specific spring or plate reverb type. Tonality is clean with minimal distortion, very low noise, and none of that metallic after-taste.
Specifications
- True bypass
- Swell (decay) control
- 0dB gain
- 82k ohm input impedance
- 0.05% distortion @ 1V
- 20Hz to 4kHz bandwidth
- 9V @ 66mA power
Downloads
Videos
Analog* Discussion
Some folk believe the PT2399 delay chip should be classified as digital. I say no! There are no digital words representing the signal, nor any such arithmetic or computing done. The input signal passes through an analog opamp for filtering, which then drives a low pass filter and comparator input. The analog comparator makes a decision to go higher or lower, and this is the information passed into the 1-bit digital memory. As I said, it is not a digital representation of a signal, but merely a decision to go higher or lower, and even then the amount of high or low depends on analog supplies, so they need to be clean. The reverse process occurs at the output of the memory, where an analog charge is pumped into or pulled out of a capacitor for each clock cycle, depending on the decision bit. This is then fed into another analog opamp configured as a low pass filter, thus removing high frequencies and sampling artifacts. That's it, a very analog process. No algorithms, no software.