Power amplifier electronic circuits-tube audio rf amplifiers

Electronic Amplifier Circuits-Power amplifier, audio amplifier designs and circuits

March 16th, 2008

18 Watt MOSFET Amplifier

About the Circuit.

This audio amplifier is of high efficiency as it produces an output power of 18W , and that too with very less components. A shunt feedback configuration is setup here using two transistors, one MOSFET, and also with a few resistors and capacitors for optimum perfo
rmance and noise free operation .Though a small circuit in appearance, the circuit using an 8 ohm speaker can produce 18 watts, or 30 watts for a 4 ohm speaker. As we are using only a few components a well regulated, highly stable power supply is to be used.Thus an improved performance as well as stability is obtained, which is necessary for obtaining a constant output for varying loads and most importantly for reducing the noise. The DC voltage regulator rating should be sufficient enough to produce more than 3 Amps at 40 volts.

Circuit Diagram & Parts List .

18w-mosfet-amp-amp-ckt.JPG

Tips .

  1. The PCB used for a circuit like this should be of high quality.
  2. In order to obtain better performance always select a good preamplifier board with a tone control prior to this amplifier.
  3. If are unable to set up a preamplifier , no need to worry because the main amplifier has enough capacity to stand on its own. Preamplifier is needed only if you notice substantial clipping in the audio output.
March 13th, 2008

25 W Bridge Amplifier Circuit

About the circuit

A superb power amplifier using TDA 2009 which can deliver a blowing 25 W rms onto a 4 Ohm speaker and 13 W rms onto a 8 Ohm load. ICTDA 2009 is actually a 2 channel amplifier each of 13W rms on 4 Ohm.Here the two are connected in bridge format to double the output power to 25W.This circuit is designed exactly as what is said in the data sheet.

Circuit Diagram

25-w-tda-2009-amp-lab.jpg
Tips

  1. Maximum possible input voltage for TDA 2009 is 24 V.Don’t exceed it.
  2. Make a bridge rectifier using four 5 A diodes if 5 ampere bridge is not available
  3. TDA 2009 must befitted with a proper size heat sink
  4. Thermal risks are very high so don’t try the circuit without heat sink.
  5. A 10K pot can be connected in series with the input as a volume control
  6. All capacitors are rated above 25 V.