Here are three of the musical instrument effects projects from Craig
Anderton's "Electronics Projects for Musicians" book.
The Bass Fuzz,
Compressor / Limiter,
and the Phase Shifter.
My plan was to build most of the projects in the book. Basically for fun and to learn from building the circuits. I made the circuit boards for the effects on this page, populated them with components and just left the boards sit unfinished for quite sometime because of the cost of enclosures and stomp box switches.
To make the circuits functional and not have a mess of wires with components hanging on them I decided to mount the components on cardboard. I tested the effects with my electric bass, work bench power supply, headphone amp and headphones.
The BASS FUZZ uses leds to clip the audio signal creating the fuzz effect and a filter to equalize the bass and treble frequencies.
This effect uses the 8 pin NE5532 op-amp in place of the original RC4739 14 pin op-amp.
The Compressor/ Limiter uses an opto-isolator and op-amps to compress and limit the audio gain. This unit has a Silonex NSL-32 opto-isolator substituted in place of the original Clairex CLM6000 part. The CLM6000 opto-isolators have been out of production for a long time.
The Compressor /Limiter seems to work fine with the Silonex opto-isolator as is.
I did change one of the resistors on the Bass Fuzz (No opto-isolators in this circuit) to increase the distortion but that may not be necessary if you have an instrument with a higher output than my Guild bass or if your happy with the sound.
I plan on doing more testing of the effects boards and adding audio clips to this web page when I get a chance.
The effects on this page use updated circuit board layouts to accommodate the use of the NE5532 op-amps used in place of the original RC4739.
The updated board layouts can be downloaded at the General Guitar Gadgets website.
Phase Shifter: This effect uses opto-isolators and op-amps to create a phase shifter or vibrato sound effect.
This effect uses four Silonex NSL-32 opto-isolators and a RC4136 quad op-amp for the phase shift stages. The other op-amp functions are handled by two NE5532 dual op-amps.