Hardware Hacking - Nicolas Collins

Hardware Hacking 91

Chapter 23: Amplification & Distortion

You will need:

• Something to amplify: a guitar, a cassette or CD player, etc.


• A breadboard.


• 4049 CMOS Hex Inverter.


• Assorted resistors, capacitors & pots.


• Some solid hookup wire.


• Assorted jacks and plugs.


• A 9 volt battery and connector.


• An amplifier.


• Hand tools.

In addition to turning sounds on and off, there are many occasions on which we
just want to make something louder (see Rule #3 of the Avant Garde.) Loudness
comes in different flavors, and a little experimenting with the 4049 Hex Inverter
demonstrates several of them. This is another example of a digital logic chip
being “mis-used” for analog purposes. Its internal configuration and pinout are
shown below. Note that the 4049 is a rare exception to the general rule of corner
pins for power hookup in CMOS chips (as in the Hex Schmitt Trigger, the NAND
Gate and the Divider circuit we used in previous chapters) If you are a
practicing dyslexic, now is the time to hold onto your hat: +9 volts connects to
pin 1 (marked “Vdd” on the schematic,) while the ground connects to pin 8 as
expected (“Vss”.) The “NC” by pins 13 and 16 indicates “no connection.”
IMPORTANT: do not substitute the 74C14 Hex Schmitt Trigger for the 4049 -- it
is an inverter, but has a different internal circuit design that won’t work properly
in these configurations.

+ 9 volts ground

4049

Preamplifier

Hook up the circuit shown below. This general purpose amplifier circuit has six
basic components: