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CW signal processor – Circuit Schematic
CW signal processor
This circuit provides interferenced rejection for the CW operator. The 567 phase-locked loop is configured to respond to tones from 500 to 1100 Hz. The Schmitt ...
Hear with Ultrasound Using Flanagan Neurophone – Circuit Schematic
Hear with Ultrasound Using Flanagan Neurophone
By mixing an audio signal with ultrasound, you can hear the audio as if it's inside your head... even if the 'headphones' are nowhere near your ears. Patrick Fl...
Passive tone-control circuit – Circuit Schematic
Passive tone-control circuit
A simple circuit using two potentiometers and easily available standard value components provides tone control....
HiFi preamp with tone control – Circuit Schematic
HiFi preamp with tone control
This preamp and tone control uses the JFET to its best advantage; as a low noise high input impedance device. All device parameters are noncritical, yet the cir...
Mike preamp with tone control – Circuit Schematic
Mike preamp with tone control
The LM318 op amp is operated as a standard non-inverting amplifier. Resistor Rl (47 k ohm) provides an input path to ground for the bias current of the non-inve...
Tone control – Circuit Schematic
Tone control
Tone control of audio systems involves altering the flat response in order to attain more low frequencies or more high ones, dependent upon listener preference....
Guitar treble boost – Circuit Schematic
Guitar treble boost
Ql is connected as an emitter follower in order to present a high input impedance to the guitar. C2, being a relatively low capacitance, cuts out most of the ba...
Electronic theremin – Circuit Schematic
Electronic theremin
This circuit has the CMOS IC doing double-duty performance. The first two inverters operate as a digital audio oscillator; the third operates as a low-gain line...
Speakerphone – Circuit Schematic
Speakerphone
The XR-T6425 Speakerphone IC makes it possible to carry on conversation without using the handset, while the user is talking into a microphone and listening fro...
Tone ringer – Circuit Schematic
Tone ringer
The MC34012 tone-ringer chip derives its power by rectifying the ac ringing signal. That signal is normally at 20 Hz and measures between 70 and 130 volts rms. ...
Dual tone decoding – Circuit Schematic
Dual tone decoding
Two integrated tone decoders, XR-567 units, can be connected (as shown in Fig. 1A) to permit decoding of simultaneous or sequential tones. Both units must be on...
Scramble phone – Circuit Schematic
Scramble phone
IC-1 and the associated circuitry form a stable audio tone generator that feeds a buffer amplifier, Ql and Q2. The tone output is taken from the emitters of the...
Tape recorder interface – Circuit Schematic
Tape recorder interface
The interface allows data to be saved on an ordinary tape recorder at a speed of 2400 bit/s. The serial stream of data Fig. 1 (A) is coded with a clock of 2400 ...
Stereo balance meter – Circuit Schematic
Stereo balance meter
To use the indicator, switch the amplifier to mono mode and adjust the balance control until both LEDs are equally illuminated....
Stereo balance tester – Circuit Schematic
Stereo balance tester
The meter will show volume and tone control balance between left and right stereo amplifiers. For maximum convenience the meter is a zero-center type. Resistors...
Funk box – Circuit Schematic
Funk box
Adjusting potentiometer R7 adds extra twang from way down low to way up high. To set the unit, adjust potentiometer R4 until you hear a whistle (oscillation); t...
Twang-twang circuit – Circuit Schematic
Twang-twang circuit
Twang is a guitar sound that more or less approximates a banjo or mandolin. The circuit produces unusual sounds from an ordinary electric guitar by cutting the ...
Autodrum – Circuit Schematic
Autodrum
The beat rate may be determined by operating a foot pedal in much the same manner as for a real drum, or by means of an internal oscillator, the speed of which...
Fuzz circuit – Circuit Schematic
Fuzz circuit
It seems that guitar fuzz boxes have been around since the beginning of rock, and have seen little improvement over the years. This one is somewhat different be...
Waa-waa circuit – Circuit Schematic
Waa-waa circuit
The waa-waa effect is achieved as certain frequencies are amplified more than others. A phase shift RC oscillator makes up the basic circuit. Negative feedback ...