Guitar effects from old compact
fluorescent light bulbs. By Andrew Carrell
When compact fluorescent lamps (CFLs) burn
out, don’t throw them out! Carefully pry apart the
base with a flathead screwdriver, and you’ll find
a tiny circuit board stuffed with useful components.
Then you can recycle just the bulb (be careful not to
break it). Removing the bulb is the first thing they
do at the recycler’s anyway.
I’ve opened up a few different brands, and the
contents are all pretty much the same. A typical
inventory includes 2 transistors, four 1N4005 diodes,
assorted ceramic capacitors and resistors, a 10μF
electrolytic capacitor, and a small coil transformer.
I don’t bother salvaging the resistors, but I use
the film caps, transistors, and diodes to make guitar
effects boxes. Fuzzes, boosts, and buffers — oh my!
Here are some CFL-based effects that I’ve concocted and had fun with. You can find the schematic
diagrams at makezine.com/19/diycircuits_cflreuse,
along with links to other CFL component projects
and DIY guitar effects resources.
» Fluorescent Fuzz and Shining Sixties Fuzz
These impart a 60s or 70s rock/psychedelic sound.
» 13 Watt Overdrive This adds some 70s rock
“crunch” to your tone.
» Light Ranger This treble booster is great for
making your guitar solos stand out and cut
through the mix.
» Bulb Booster This makes your signal louder,
pushes your amp harder, and generally makes
everything sound better.
The schematics online show the core circuits. For
a volume control, add a potentiometer between the
circuit’s output and the output jack on the box, with
the third contact going to ground. Using a stereo
jack for input lets you either activate the effect
circuit or bypass it, depending on whether the 3PDT
step switch connects to the right or left channel.
For all of these, you solder the circuits onto a small
piece of perf board, then add leads to connect out to
the battery snap and input/output jacks. To secure
the circuit board inside the box, I use velcro tape.
For inspiration and help with my various DIY
audio projects, I give credit to diystompboxes.com,
120 Make: Volume 19
MATERIALS AND TOOLS
Old CFL bulb
Resistors Values vary for different effects;
see schematics online at makezine.com/19/
Small perf board
¼" audio jacks, 1 stereo and 1 mono
3PDT (triple pole, double throw) step switch available
from Pedal Parts Plus ( pedalpartsplus.com),
Small Bear Electronics ( smallbearelec.com),
or diystompboxes.com. You can also use a DPDT
(double pole, double throw) switch, but that’s
Case available from Pedal Parts Plus or Small Bear
Electronics. Or you can use any small, strong box
(like a circuit junction box), or make your own.
muzique.com, buildyourownclone.com/board, and
geofex.com. They all host great communities with
Andrew Carrell caught the electronics bug from his Dad and
currently makes music (and sometimes noise) in Austin, Texas.
Photograph by Ed Troxell
for schematics, resources, and links to more CFL