The Double D is a guitar pedal that offers two channels of distortion. It utilizes all six inverters on the 4049 IC chip to avoid wasting unused inverters. The design goals were to have 1M or better input impedance, a buffered output to avoid loading the inverters, and to create two independent overdrive channels with gain and volume controls for each.

The first channel, called “Jiggle,” provides classic amp-like sounds at various settings of the gain knob. The second channel, called “Bounce,” uses three inverters to crank the gain up higher. Caps are used over the inverters to mellow the clipping out, and rolling back the treble in earlier clipping stages helps bring out amp-like sounds and remove harsh high-end frequencies.

One downside of this design is its high current consumption, measuring 22.8mA on one of the prototypes. It is recommended to use a 9V adapter due to the high current draw. Various methods of controlling the power supplied to the 4049 have been suggested to reduce current consumption.

Summary created by AI from the original source.