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Can be directly connected to CD players, tuners and tape recorders. Do not exceed 23 + 23V supply. Q3 and Q4 must be mounted on heatsink. D1 must be in thermal contact with Q1. Quiescent current (best measured with an Avo-meter in series with Q3 Emitter) is not critical. Adjust R3 to read a current between 20 to 30 mA with no input signal.

This circuit is a 1 watt mono amplifier using the TDA 7052 from Philips. It is designed to be used as a building block in other projects where a battery powered audio amplifier is required to drive a small speaker. It will operate best from 6 – 12 V DC and requires no heatsink for normal use.

20W TDA2005 stereo amplifier for all suitable applications like amplifying medium power speakers. It is suitable for car use but before, the power supply must be choked with at least 150mH and it must give up to approximately 6 to 7 amps during the upstream performance.

The Circuit present here is a 20Watts Car Stereo Amplifier. The main features of this powerful MULTIWATT® package (a trademark of SGS-THOMSON Microelectronics), a power amplifier IC chips designed specifically for car radio application, are the high current capability (3.5A) and the capability to drive a very low impedance (down to 1.6R). Here is the schematic diagram of the standard circuit as shown in its data sheet.

This article describes how to build 200W Leach Amplifier from Mr. Marshall Leach known like “The Leach Amp”. Article about building of this amplifier I found later in journal A_Radio Praktická elektronika 11/2002. For many years I looked for construction of HiFi amplifier wit a good parameters, enough power reserve and simple construction. I built a couple of amplifiers with integrated circuits MBA810, TDA2005, LM3886, but I was disappointed by their output quality and noise. I decide to built a classic construction with discrete components and bipolar transistors. Construction from Mr. Dudek was interesting, but I didn’t like used components and complexity. All of my requirements satisfied construction of the Leach Amp. Circuit author publicates in a February 1976 in american journal. From these days circuit was not practically changed. Little changes are described on authors page. I succeeded to find almost all original components on our local market, which was a miracle. Only a bigger problem was a power transformer and filter capacitors. Recommended toroid transformer for power 200W to 4 ohms is 230V/2x 42V.

Article about building Marshall 200W Leach Amplifier. For many years I looked for construction of HiFi amplifier wit a good parameters, enough power reserve and simple construction. I built a couple of amplifiers with integrated circuits MBA810, TDA2005, LM3886, but I was disappointed by their output quality and noise. I decide to built a classic construction with discrete components and bipolar transistors. Construction from Mr. Dudek was interesting, but I didn't like used components and complexity. All of my requirements satisfied construction of the Leach Amp. Circuit author publicates in a February 1976 in american journal. From these days circuit was not practically changed. Little changes are descripted on authors page.

A compact audio powerhouse ideal for guitar or PA work or for use as a general-purpose subwoofer or hifi amplifier. Many people prefer Mosfets because of their legendary ruggedness. Altronics had a Mosfet amplifier module which produced 200W into a 4 Ohm load and so we decided to take a look it. It turned out to be based on the "Pro Series One" as mentioned above, although this version by Altronics has been derated and adapted to different Mosfets. It has a rated power output of 140W into 8W and 200W into 4 Ohm. Frequency response is within 1dB from 20Hz to 80kHz. Total harmonic distortion is rated at less than 0.1% up to full power and signal-to-noise ratio with respect to 200W is better than 100dB unweighted.

This amplifier is a standard datasheet aplication of Tripath TA-2020-020 T-class IC. It offers 20W on 4ohm load with efficienty of up to 88%. The whole amplifier was bought as a AMP6 kit from 41hz.com. The PCB board looks really good and the copper on both sides is quite thick. The kit contains only high quality components such as 1% metal film resistors or Panasonic FC input capacitors. Because of such high efficienty the chip doesn't really require a heatsink. I used such a big one only because I had it. Before starting soldering please read the Assemble Manual so that even beginers will cope with building this amplifier. For more information you can visit the AMP 6 forum.

This is an instrument amplifier for monitoring music when on stage. It provides 21W output power of this little design. Previously I had a decent 10W amplifier (RED Free Circuits), but we blew that one somehow. Now I will put this into the old box. I haven't built it yet, but the simulations say it works as I designed. In this design, wiring is important due to no differential amplifier. I might need to add ripple rejection with a zener as in the above design.

The supply voltage can be between 34V and 46V and the quiescent current should be set to 1.7A measured through R25 (a voltage of 0.75V must be measured over R25 for a quiescent current of just under 1.7A). R23 is a trimmer and must be set to maximum resistance (10kOhm) when powering up. Then the resistance of R23 must be decreased until the the quiescent current is achieved. If the amplifier is mounted on a big enough heatsink ( 0.6K/W at most) then the amplifier is very safe from thermal runaway. Intelligence must be used when choosing power and voltage ratings of resistors and capacitors.