#249 TDA2050 Guitar Practice Amp
Single-channel 10W guitar practice amplifier based on the TDA2050
Here’s a quick demo, clean tone from a Spanish guitar with built-in pickup:
Notes
This is a 10W guitar practice amplifier circuit and was designed for the Fundamentals of Audio and Music Engineering: Part 1 Musical Sound & Electronics course offered by University of Rochester on Coursera.
The amplifier itself is designed to teach simple tone and distortion circuitry.
Parts
| ID | Qty | Value | |
|---|---|---|---|
| R1 R3 R4 | 3 | 1 MΩ | |
| R2 | 1 | 5.6 kΩ | |
| R5 | 1 | 1 kΩ | |
| R7 R14 R16 | 1 | 22 kΩ | |
| R6 | 1 | 4.7 kΩ | |
| R15 | 1 | 2.2 kΩ | |
| R9 | 1 | 100 kΩ | |
| R8 | 1 | 10 kΩ | |
| R13 | 1 | 1 Ω | |
| R10 | 1 | B50KΩ pot | |
| R11 | 1 | B10KΩ pot | |
| R12 | 1 | A10KΩ pot | |
| C2 | 1 | 47nF 473 | |
| C10 | 1 | 100nF 104 | |
| C3 | 1 | 10nF 103 | |
| C7 | 1 | 220nF 224 | |
| C9 | 1 | 100µF electrolytic | |
| C8 | 1 | 1000µF electrolytic | |
| C1 C4 C5 C11 | 4 | 1µF electrolytic | |
| C6 | 1 | 10µF electrolytic | |
| U1 | 1 | TL072 DIP8 |  |
| U2 | 1 | TDA2030 |  |
| D1 D2 | 2 | 1N4001 | |
| LED1 | 1 | 3mm Red LED | |
| SPKR1 | 1 | 4Ω 10W | |
| S1 | 1 | SPDT switch | |
| J1 | 1 | 12V power connector | |
| J2 | 1 | 6.35mm mono socket |
Hardware and other parts:
- DIP8 IC socket (for the TL072)
- SPDT power switch
- 2.1mm power jack
- 12V DC power supply
- 1⁄4” Phono plug
- speaker
- perfboard/PCB
Cabinet Design - TODO
Some reasonable dimensions:
- A well rounded frequency response translates to a cabinet volume of roughly 5832 cm^3, or interior dimensions of 18 cm x 18 cm x 18 cm.
- For a bass heavy amplifier, a cabinet volume of roughly 2754 cm^3 will work better. This corresponds to interior dimensions of 18cm x 18cm x 8.5cm.
Styrofoam board can be used for a quick build, but a wooden case will sound slightly better.
I’ve mounted mine in a wooden box of about 2700 cm^3 volume, with a removable rear panel so I can experiment with tone.
Performance
Sample oscilloscope trace:
- 12V power
- CH1: input (1kHz, 20mV sine)
- CH2: output, minimum gain & tone
Construction
