Jacob Brotman-Krass
Creating New Sound
Analog electronic components, acrylic, maple plywood
Artist Background
Jacob Brotman-Krass is a third-year Physics student at William & Mary. Combining his love for playing the electric guitar and woodworking with his studies in electronics, Jacob has been designing and constructing guitar effect pedals for the past year, tuning and refining each pedal to his desired sound. He is currently working on an album, which will feature many of the new pedals he has been making.
About the Work
Like much of modern technology, many effect pedals nowadays are digital; however, these digital pedals are just attempts at replicating the rich and unpredictable sounds of their analog counterparts. The two effect pedals featured here, square wave (clear acrylic) and tremolo (maple plywood), were made with only analog components, designed and fine-tuned through a combination of electrical theory and good-old fashioned experimentation. The end result is a pair of pedals that range from pleasant and woozy to wild and glitchy.
The square wave pedal operates like the name suggests, turning a standard smooth audio wave into one with sharp edges, giving the effect a harsh, distorted sound--great for guitar solos and harder rock. The tremolo, on the other hand, is a time-based effect that adjusts the signal volume back and forth between loud and soft. With the effect frequency set faster, this pedal makes rhythm guitar shimmer; on slower settings, tremolo gives synths and keyboards a hypnotic drone.
Details
Using the capacitors and resistors labeled C0 and R0, the 9V power is split into a +4.5V and -4.5V so guitar signal can be processed without clipping.
U1, a 741 operational amplifier, is essentially pushed to maximum gain, such that the wave would be far larger than V+ and V-, which power the amplifier. However, this is impossible--the wave is instead clipped anytime the signal is amplified to be larger than the limits of the power supply. Instead of a normal, rounded audio wave, this becomes a blocky square wave.
At the end of the circuit, C1 and the potentiometer (POT1) combine to form an adjustable high-pass filter. This was added as a personal touch--when the knob is cranked and most lower frequency sounds are filtered out, the distorted guitar signal has a tinny, glitchy sound.