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45 Watt Class B Amplifier

45 Watt Class B Amplifier Description 45W into 8 Ohm - 69W into 4 Ohm Easy to build - No setup required45 Watt Class B Amplifier Description


The main design targets for this amplifier were as follows:
Output power in the 40 - 70W rangeSimple circuitryEasy to locate, low cost componentsRugged performanceNo setup
These goals were achieved by using a discrete-components op-amp driving a BJT complementary common-emitter output stage into Class B operation. In this way, for small output currents, the output transistors are turned off, and the op-amp provides all of the output current. At higher output currents, the power transistors conduct, and the contribution of the op-amp is limited to approximately 0.7/R11. The quiescent current of the op-amp biases the external transistors, and hence greatly reduces the range of crossover.

The idea sprang up from a letter published on Wireless World, December 1982, page 65 written by N. M. Allinson, then at the University of Keele, Staffordshire.
In this l…

Power Amplifier 60 Watt supply voltage 30 - 60 Volts

Power Amplifier 60 Watt supply voltage 30 - 60 Volts
This is a simple and low cost 60W power amplifier. The optimal supply voltage is around 50V, but this amp can work from 30 to 60V. The maximum input voltage is around 0.8 - 1V. As you can see, in this design the components have a big tolerance, so you can build it with almost any components that you can find at home. The output power transistors can be any NPN types, but do not use Darlington types.
Capacitor C1 regulates the low frequencies (bass), as the capacitance grows, the low frequencies are getting louder. Capacitor C2 regulates the higher frequencies (treble), as the capacitance grows, the higher frequencies are getting quieter. 
This is a class B amplifier, this means, that a current must flow through the end transistors, even if there is no signal on the input. This current can be regulated with the 500 Ohm trimmer resistor. As this current increases, the sound of the amplifier is better, but output transistors are dispat…

Guitar Amps

General Description


This design adopts a well established circuit topology for the power amplifier, using a single-rail supply of about 60V and capacitor-coupling for the speaker(s). The advantages for a guitar amplifier are the very simple circuitry, even for comparatively high power outputs, and a certain built-in degree of loudspeaker protection, due to capacitor C8, preventing the voltage supply to be conveyed into loudspeakers in case of output transistors' failure. The preamp is powered by the same 60V rails as the power amplifier, allowing to implement a two-transistors gain-block capable of delivering about 20V RMS output. This provides a very high input overload capability.
Features:

Sensitivity: 35mV input for 40W 8 Ohm output42mV input for 60W 4 Ohm output Frequency response: 50Hz to 20KHz -0.5dB; -1.5dB @ 40Hz; -3.5dB @ 30Hz Total harmonic distortion @ 1KHz and 8 Ohm load:Below 0.1% up to 10W; 0.2% @ 30W Total harmonic distortion @ 10KHz and 8 Ohm load: Below 0.15% up to 10W;…

18W+18W Stereo Amplifier

General Description:
The TDA7265SA is class AB Dual Audio Power amplifier assembled in the @ Clipwatt 11 package, specially designed for high quality sound application as Hi-Fi music centers and stereo TV sets. The TDA7265SA is pin to pin compatible with TDA7269, TDA7269A, TDA7269SA, TDA7265,TDA7499, TDA7499SA. 
Circiut Diagram:

1W Per Channel Stereo Class-D Audio Power Amplifier

Features
1 watt per channel with 8-ohm loadMax. efficiency » 80% with 8-ohm load at 5 voltsFilterlessDigital gain controlBuild-in depop circuitryError protection for short circuit and over-temperatureMute (shutdown) current < 1µA typicalLow operating current (4mA at 5 volts without load)TSSOP 24L package available 
General Description The AP130 is an oversampling class-D power amplifier for  stereo audio applications. It provides high power-efficiency for filterless 8-ohm load. Build-in depop, mute and gain control features simplify the applications. BTL (Bridge-Tied-Load) configuration delivers up to 1 watt into 8-ohm load per channel at 5-V supply voltage. It allows direct coupling of the power signal. Reliability is improved through over-temperature and short circuit protections. The class-D power amplifier enables high efficiency applications for portable devices.
Circuit Diagram