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Fuzz box 4 – Circuit Schematic
Fuzz box 4
None of the components are particularly critical in value or quality, as distortion is the sole object...
Fuzz box 3 – Circuit Schematic
Fuzz box 3
Q1 and Q2 form a voltage amplifier which has sufficient gain to be overdriven by a rela-tively low input, such as an electric guitar. The result is that the out...
Fuzz box 2 – Circuit Schematic
Fuzz box 2
Potentiometer R3 sets the degree of fuzz, and R8 sets the output level...
Fuzz box 1 – Circuit Schematic
Fuzz box 1
The input signal is amplified by the transistors. The distorted output is then clipped by the two diodes and the high frequency noise is filtered from the circu...
Tunable notch filter to suppress hum – Circuit Schematic
Tunable notch filter to suppress hum
This narrow-stop-band filter can be tuned by the pot to place the notch at any frequency from 45 to 90 Hz. It attenuates power-line hum or other unwanted signal...
LED bar peak program meter display for audio – Circuit Schematic
LED bar peak program meter display for audio
A bar column of LEDs is arranged so that as the audio signal level increases, more LEDs in the column light up. The LEDs are arranged vertically in 6 dB steps. ...
Sca background music decoder – Circuit Schematic
Sca background music decoder
A resistive voltage divider is used to establish a bias voltage for the input (pins 2 and 3). The demodulated (multiplex) FM signal is fed to the input through ...
Magnetic pickup phono preamplifier – Circuit Schematic
Magnetic pickup phono preamplifier
This preamplifier provides proper loading ratio of better than - 70 dB (referenced to 10 to a reluctance phono cartridge. It provides mV input at 1 kHz) and has...
Novel loudspeaker coupling circuit – Circuit Schematic
Novel loudspeaker coupling circuit
The ground side of the speaker is connected to the junction of two equal high value capacitors (1000 µf is typical) across the supply. The amplifier output v...
Tone encoder – Circuit Schematic
Tone encoder
A basic twin-T circuit uses resistors for accurately setting the frequency of the output tones, selected by pushbutton...
Four channel mixer – Circuit Schematic
Four channel mixer
High gain op amp combines up to four individually controlled input signals...
Hybrid mixer – Circuit Schematic
Hybrid mixer
ICla and b are biased into the linear regions by R3 and R4. (ICI must be 4011A)...
Silent audio switching-mixing – Circuit Schematic
Silent audio switching-mixing
Two or more signals can be switched and/or mixed without annoyingclicks by using FETs...
One transistor audio mixer – Circuit Schematic
One transistor audio mixer
Three or more inputs with individual level controls feed into the base of Q1...
Passive mixer – Circuit Schematic
Passive mixer
This simple circuit can be used to combine stereo signals to produce a monaural output...
Two channel panning circuit – Circuit Schematic
Two channel panning circuit
This panning circuit (short for panoramic control circuit) provides the ability to move the apparent position of one microphone"s input between two output chann...
High-level four-channel mixer – Circuit Schematic
High-level four-channel mixer
To provide good signal-to-noise ratio, this four channel mixer amplifier controls the signal levels after the amplifiers, and then mixes them to offer a combine...
Four-input stereo mixer – Circuit Schematic
Four-input stereo mixer
Four (or more) inputs can be mixed and produce stereo output. Gain of each stage can be boosted by adding RX, but it should be kept below 50 (RX above 2 K) to a...
Audio mixer – Circuit Schematic
Audio mixer
The 741 op amp is used as a summing amplifier to combine several audio inputs...
Automatic tape recording – Circuit Schematic
Automatic tape recording
Amateurs don"t have to miss the action while away from the rig. This circuit turns on a tape recorder whenever the receiver"s squelch is broken...