TDA2030A 14 W Speaker Amplifier
Turn a line-level audio signal into 14 watts of bookshelf-speaker output with one heat-sinked chip and a handful of resistors.
Difficulty: Through-hole. Estimated build time: about 60 minutes. Estimated parts cost: about US$7.00. 6-line bill of materials. Compare supplier offers when available. A discrete class-AB power amplifier built around the ST TDA2030A in its iconic Pentawatt-5 (TO-220-5) package.
Build the dual supply
The cleanest setup is a ±15 V split supply from a 30 VAC centre-tapped transformer through a bridge rectifier and two 4700 µF filter caps — but for a first build, two 9 V batteries in series with the midpoint as ground works. Pin 5 of the TDA2030A is GND, pin 3 is V_S− (∕9 V), pin 5 is V_S+ (+9 V). Decouple with 100 nF ceramic and 100 µF electrolytic close to the chip.
Set the gain network
Pin 1 is the inverting input. Wire a 22 kΩ from pin 1 to ground in series with a 470 nF (DC blocking), and a 680 kΩ from pin 1 to pin 4 (output). Gain is 1 + 680/22 ≈ 32, which is the standard recommendation. Pin 2 is the non-inverting input — connect it through a 22 kΩ to ground and a 470 nF series cap to the input RCA jack.
Add the output Boucherot network
From pin 4 (output) to GND, wire a 1 Ω resistor in series with a 220 nF ceramic cap. This snubber kills any high-frequency oscillation if you connect a long speaker cable. Skip it and the amp may sing at 100 kHz when you wave the cable around.
Wire the speaker and test
Connect a 4–8 Ω speaker between pin 4 and GND through a 470 µF output coupling capacitor (so DC offset doesn’t fry the voice coil). Power up. Touch the input — you should hear hum. Plug in a phone and play music at low volume first. The chip itself MUST have a heatsink for any sustained volume; bare it will thermally shut down within seconds at full power.