Discrete Guitar Transistor Amplifier

470

07:14:34

Class AB BJT amplifier designed for a guitar input.
From left to right:
=> Source and 10kOhm load represent 
     guitar input signal
=> Preamplifier. High input impedance. 
     Gain  approximately 10V/V. Can be 
     adjusted by replacing the 1kOhm 
     collector resistor with a potentiometer. 
     Set higher for soft- to hard-clipping 
     (distortion)
=> Common emitter gain stage. Emitter 
      bypass capacitor sets AC gain by 
      creating a smaller parallel resistance at 
     the emitter for AC signals. DC stability 
     is maintained.
=> High input impedance buffer stage with 
      small output impedance, used for 
      improved loading factor and stage 
      isolation.
=> Class AB complementary push-pull 
    power output stage, with cascode 
    common collector inputs used to bias 
    the output  stage, mitigating cross-over 
    distortion. 

Specs (Maximum):

Maximum peak input: 70mV
Max output swing: -8.04V to 7.93V
Voltage Gain: 120 V/V
RMS Power To Load: 8W
Power Draw: 36.645W
Power Added Efficiency: 21.834%

published 6 years ago

zorgrian

6 years ago

Electric guitars peak @ >1volt!!!

calvin21

6 years ago

@zorgrian Not quite. This might be true for most modern pick-ups, but I specifically designed this for my guitar which outputs at the very most 100mv peak. I built the physical circuit and it works perfectly with my guitar with almost no distortion.

calvin21

6 years ago

If, however, you do wish to use it for a 1V peak input, you can simply replace the 1kOhm preamp collector resistor with a 65 Ohm resistor. That's why I suggest using a potentiometer here, because you can easily adjust the gain this way.

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.