Mini Audio Amplifier with LM380

This is the very simple circuit of mini audio amplifier single channel / mono using low cost IC LM380. For stereo application, just build the identical circuit.

The circuit shown in Figure 1 is a very simple audio power amplifier. The main component of this circuit is the LM380 audio amplifier. The simplicity of this circuit is made possible by the LM380's minimal requirements for external components, since it is already internally equipped with the necessary biasing, compensation, and gain circuits for audio amplification.

250 milliwatts Amplifier with TDA2822

This is 250 milliwatts amplifier scheme design with TDA2822. This low power amplifier generates 250 mW on each channel, can be used for general purposed application such as walkman, mp3 player, radio etc. This may well configured to operate in stereo or bridge, which is obtained more power in mono channel.

Stereo OTL Audio Amplifier

The following diagram is the circuit of Stereo OTL Audio Amplifier. It based on IC circuit, so the circuit looks simple. You can use IC LM379,LM377,LM378 for this amplifier project.

Mini Micropone Amplifier Circuit

This is the schematic diagram of mini microphone amplifier circuit, which all of the active components are based on transistor. This circuit project is called "mini" since its size is small and the output is small too. It uses surface mount technology.

Circuit works

120W Power Amplifier Circuit - Leach Amp

Here the 120W power amplifier claimed to be a very good sounding design.

The circuit is complex, so it will hard enough to build manually by yourself. The design of PCB layout is already presented, but it still hard enough to construct. I do not recommend that you create the circuit boards unless you have experience in doing it.

High Gain Stereo Tube Preamplifier

This is the circuit diagram of stereo tube preamplifier, give you high gain with high performance output. This circuit should work fine with a 6J5, 12SX7, 6CG7, or 12AU7 as the lower tube, and a 6BX7, 12B4, or triode-connected 6BQ5 as the upper tube. Any of the miniature TV dual triodes such as 6DE7 or 6EW7 can serve as both top and bottom triodes since they contain a medium-mu and a low-mu section. (This wouldn't be my choice, since the octals seem to sound better, but you may choose the tubes you like.)

2x6W Stereo Audio Amplifier based LA4440 Power IC

This is the diagram of 2x6W stereo audio amplifier based LA4440 power IC. Actually, the LA4440 can be used in both stereo mode and mono (bridge) mode, but the circuit presented in this post is LA4440 in stereo mode. The recommended power supply is 13.2V, while the maximum voltage rated at 18V.

50W Power Amplifier Circuit using STK084

This is the circuit diagram of 50W power amplifier circuit which built based on single power amplifier chip of STK084. It's an well-known old IC for audio frequency (AF) amplifier.

50W Audio Amplifier Circuit

Here the 50W audio amplifier circuit diagram. The amplifier is based ICL8063. This a good amplifier circuit which is easy enough to built.. This circuit can be connected by radio, TV, stereo or other devices.

22W Audio Amplifier with TDA1554

Here the 22W audio amplifier which is low cost and very easy to build. You can use this circuit as a booster in a car audio system, an amplifier for satellite speakers in a surround sound or home theater system, or as an amplifier for computer speakers

Circuit Notes

2 Way Active Speaker with STK4042

Active speakers have many advantages over the simple speakers using passive materials for implementing the components separation of frequencies. In the case of active speakers have proportionally higher manufacturing costs, since each loudspeaker is driven by its own amplifier. In a properly designed active speaker, the sound quality is much better and very low distortion, because it uses inductors and capacitors in the signal path,. Those capacitors are on the path of the signal have a very small price and very good quality. This does not mean that a well designed passive speaker is good, maybe better than an active. Unlike an active speaker is much more difficult to manufacture.

TDA2030 : 15W OTL Audio Amplifier Circuit

This is the circuit diagram of 15W OTL audio amplifier based single power IC TDA2030.

The TDA2030 is a popular power chip for low power amplifier circuit. The circuit will deliver about 15W audio power when use 8ohm loudspeakers. For maximum power output, you need 24VDC power supply with 1A current, for single/mono channel. Use power supply with 2A minimum output current for stereo channel. Do not forget to mount a heatsink on the IC.

Class-AB Headphone Amplifier Circuit

This is the circuit diagram of Class-AB headphone amplifier which built using 3 transistors of BC549 and BC559. The circuit is very simple and will give you good audio performance.

The power consumption of this headphone amplifier circuit is claimed to be very low. Two pieces of AA battery will supply the circuit for long time.

Components List:

R1 - 100K R2 - 330 R3 - 100 R4 - 22 (2 - 4.5V) R4 - 100 (5 - 12V) C1 - 4.7uF

C2 - 4.7uFC3 - 100 - 1000uF C4 - 220uF P1 - 100K D1, D2 - 1N4148 Q1, Q2 - BC549 Q3 - BC559

60W Class AB Audio Amplifier with TDA7294

Here is the circuit diagram of 60W class AB audio amplifier which is built based power IC TDA7294. The TDA7294 amplifier module is a monolithic integrated circuit. It's meant for use as an audio class AB amplifier in hi-fi applications. It has a wide voltage range and output current capability, enabling it to supply the highest power into both 4 ohm and 8n ohm loads. Using the addition of a handful of components and also a appropriate power source, this module will achieve 50W RMS into 8-ohm with 0.1% THD.

You have to provide a heavy duty heatsink rated at 1.4°C/W. Pin 10 will be the MUTE input and pin 9 provides you with a STANDBY mode. Muting ought to always take place just before standby mode is used. Connecting these pins permanently to the power supply rail (insert links) makes sure that the amplifier comes on instantly on power up. Extending the time constants R3-C6 and R4-C5 may possibly eliminate any switch-on clicks. The IC has internal thermal protection that causes the mute to cut in at 145°C and switches the amplifier into standby at 150°C. Don't operate the module without having a heatsink. The heatsink tab on the TDA7294 IC is internally connected towards the negative supply rail. When the module is mounted inside an earthed metal enclosure then the IC has to be insulated from the heatsink. If not, the negative supply rail is going to be shorted to ground.


Power Supply for 60W Class AB Audio Amplifier:

30W Class AB Power Amplifier Circuit

30W Class AB power amplifier circuit diagram using power transistor. Set the above amplifier up by adjust the variable resistor R1 to maximum and R12 to zero. After this set up is done, the activate / turn on the amplifier. Adjust the R1 so that the measured output offset is between 30 and 100mV. Once set, adjust the R12 slowly to achieve a quiescent current of around 120mA. Keep checking the quiescent current as the amplifier heats up as it might change due to voltage drop changes in the output devices because of the heat. The heatsinks should be 0.6K/W or less for two amplifiers.

Power supply circuit for 30W class AB power amplifier:

45W Power Audio Amplifier Circuit with HEXFET

This is 45W power audio amplifier circuit which built using HEXFET IRF9540 and IRF540. This is a ideal solution for the make a good, low cost power amplifier circuit.

Components List:

R1 = 47K ohm	C1-2-6-7 = 100nF 100V MKT	Q5-6 = IRF9540
R2-12 = 1K ohm	C3-4 = 22uF 25V	Q7-8 = IRF540
R3-4 = 3.3K ohm	C5 = 220pF styroflex	TR1 = 5K ohm trimmer multiturn
R5 = 1.2K ohm	C8-9 = 4700uF 63V	TR2 = 1K ohm trimmer multiturn
R6 = [1.2K ohm] 820 ohm *See text	C10 = 1uF 100V MKT	F1-2 = fuse 3A
R7 = 270 ohm	D1-2 = 15V 0.5W zener	J1 = 2pin connector 2.54mm step
R8 = 220 ohm	IC1 = LF411orAD711or LF351	J2 = 5pin connector 5mm step
R9 = 27K ohm	Q1 = BC550C
R10-11 = 22K ohm	Q2 = BC560C	All Resistors 1/4W 1% metal film
R13-14-15-16 = 150 ohm	Q3-4 = BC547B

The preamplifier and the driver support in a operational amplifier [IC1]. The voltage fall in resistors R5 and TR2/R6, drive the output FET's gates and is proportional with the input signal level. Transistors Q1-2 function as voltage stabilizers in the supply lines, but ensure also the essential voltage fall, because the IC1 it should not they are supplied with voltage bigger ± 18V. The consumption of all types that can be used in the place of IC1, are 2 mA, this it means voltage fall in terminal the R5 and TR2/R6 equal with the 2.4 until 2.6Volts. The current regulation it become from transistors Q3-4 in Wilson connection and the current adjustment of bias it becomes from the multiturn TR1 trimmer.

Detailed information about this 45W power audio amplifier circuit with HEXFET:
http://users.otenet.gr/~athsam/power_amplifier_45w_hexfet_eng.htm

30W Transistored Amplifier Circuit with Low Distortion Feature

This is the 30W transistored amplifier circuit diagram featuring ultra low distortion. The circuit use MJE2011 and MJE2021 power transistor as the final amplification. Although this is an old circuit, but it doesn't lose the modern amplifier with power ICs and power MOSFETs.

30W transistored amplifier circuit page source: http://www.4qdtec.com/pwramp.html

Simple 2 Transistor Headphone Amplifier

This is the schematic diagram of very simple headphone amplifier circuit. The circuit built using two NPN transistors. You can use transistor BC549C or other NPN transistors such as European equivalent: BC548C, BC547C, BC239, 2N5818 or 2N2222

TDA1521 - 12W Stereo Amplifier Circuit

This is the circuit diagram of 12W stereo audio power amplifier. The amplifier powered by a single power chip TDA1521. The TDA1521 contains two amplifier module. The TDA1521 has two input channel and two output channel, so, you'll only need a TDA1521 for a stereo amplifier circuit.

Source: 12W stereo amplifier

20W Power Amplifier Circuit based TDA2040

The following diagram is the circuit diagram of power amplifier based power IC TDA2040. The circuit capable to deliver power audio output up to 20W with single power supply. The TDA2040 is intended for use as a class AB audio amplifier.

The TDA2040 delivers great output current and has quite low harmonic and cross-over distortion. Further the device incorporates a patented short circuit protection program comprising an arrangement for automatically limiting the dissipated power so as to keep the working point on the output transistors within their secure operating area. A thermal shut-down method is also included.

You can download the TDA2040 datasheet here

20W Power Amplifier Circuit based TDA2040