Mini Guitar/Bass Amplifier
Circuit diagram:
Parts:
- P1______________1M Linear Potentiometer
- P2____________100K Log Potentiometer
- R1_____________68K 1/4W Resistor
- R2____________470K 1/4W Resistor
- R3______________2K7 1/4W Resistor
- R4______________8K2 1/4W Resistor
- R5____________680R 1/4W Resistor
- R6____________220K 1/4W Resistor
- R7_____________39R 1/4W Resistor
- R8______________2R2 1/4W Resistor
- R9____________220R 1/4W Resistor
- R10_____________1R 1/4W Resistor
- R11___________100R 1/2W Resistor
- R12_____________1K5 1/4W Resistor
- C1____________100pF 63V Polystyrene or Ceramic Capacitor
- C2,C5,C9,C14__100nF 63V Polyester Capacitors
- C3____________100µF 25V Electrolytic Capacitor
- C4_____________47µF 25V Electrolytic Capacitor
- C6______________4n7 63V Polyester Capacitor
- C7____________470pF 63V Polystyrene or Ceramic Capacitor
- C8______________2µ2 25V Electrolytic Capacitor
- C10___________470µF 25V Electrolytic Capacitor
- C11____________22nF 63V Polyester Capacitor
- C12__________2200µF 25V Electrolytic Capacitor
- C13__________1000µF 25V Electrolytic Capacitor
- D1______________3mm red LED
- Q1____________BF245 or 2N3819 General-purpose N-Channel FET
- IC1_________TDA2003 10W Car Radio Audio Amplifier IC
- SW1,SW2________SPST toggle or slide Switches
- J1____________6.3mm Mono Jack socket
- J2____________6.3mm Stereo Jack socket (switched)
- J3_____________Mini DC Power Socket
- SPKR__________4 Ohm Car Loudspeaker 100 or 130mm diameter
Comments:
Tiny, portable Guitar Amplifiers are useful for practice on the go and in bedroom/living room environment. Usually, they can be battery powered and feature a headphone output. This project is formed by an FET input circuitry, featuring a High/Low sensitivity switch, followed by a passive Tone Control circuit suitable to Guitar or Bass. After the Volume control, a 6W IC power amplifier follows, powered by a 12-14V dc external supply Adaptor or from batteries, and driving a 4 Ohm 10 or 13cm (4"/5") diameter car loudspeaker. Private listening by means of headphones is also possible.
Notes:
- Connect the output Plug of a 12 - 14V dc 500mA Power Supply Adaptor to J3
- Please note that if the voltage supply will exceed 18V dc the IC will shut down automatically
Technical data:
- Output power (1KHz sinewave): 6W RMS into 4 Ohm at 14.4V supply
- Sensitivity: 50mV RMS input for full output
- Frequency response: 25Hz to 20kHz -3dB with the cursor of P1 in center position
- Total harmonic distortion: 0.05 - 4.5W RMS: 0.15% 6W RMS: 10%
Tone Control Frequency Response:
