Many hobby electronics enthusiast and electronics amplifier designers are looking to build fast moving amplifier boards. The LM1875 IC based stereo amplifier board is one of them. So I decided to give the circuit and PCB layout with downloadable files of LM1875 IC based amplifier circuit.
If the cost of LM1875 is very high, when you are enquired? don’t worry you can use low cost TDA2030A IC as an alternative but the voltage handling and output power is different. You need to know the working voltage and output RMS of the TDA2030 IC before replacing with LM1875.
LM1875 Stereo Amplifier Board Circuit
This stereo board is designed very neat and easy to understand its connections and wirings. Because the IC has only 5 pins, no complex connections. inverting and non inverting inputs with positive and negative supply pins along with an output pin.
Recommended to use 104 capacitor as the box type for better audio performance. because I noted that the box type capacitors has the good quality compared with the tiny disc shape capacitors. You can also check with my statement. ” Experiences makes you perfect”.
Components Required
| Sl. No | Component Type | Value / Part | Quantity |
|---|---|---|---|
| 1 | IC | LM1875 | 2 |
| 2 | Resistor | 20K | 2 |
| 3 | Resistor | 22K | 2 |
| 4 | Resistor | 1K | 2 |
| 5 | Resistor | 1Ω (marked “1”) | 2 |
| 6 | Capacitor (Electrolytic) | 100µF | 4 |
| 7 | Capacitor (Electrolytic) | 22µF | 2 |
| 8 | Capacitor (Electrolytic) | 2.2µF (marked 2u2) | 2 |
| 9 | Capacitor (Ceramic/Film) | 224 (0.22µF) | 2 |
| 10 | Terminal Block | Input (L, G, R) | 1 |
| 11 | Terminal Block | Power (+V, 0, -V) | 1 |
| 12 | Speaker Output Terminals | L & R outputs | 2 |
As per the original datasheet of LM1875, it can give the output watts of 20 at 8ohms speaker. The working voltage must be +/- 25V DC needed.
I recommended to use +/- 20V DC supply for this circuit for better performance and heat management. You can select the value of the capacitors according to the DC supply voltage.
