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:
