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There is one amplifier configuration that is universally accepted as the ideal for audio use: Class A operation. Many early amplifiers operated in Class A, but as output powers rose above 10W the problems of heat dissipation and power supply design caused most manufacturers to turn to the simpler, more efficient Class B arrangements and to put up with the resulting drop in perceived output quality.

Why Class A? Because, when biased to class A, the transistors are always turned on, always ready to respond instantaneously to an input signal. Class B and Class AB output stages require a microsecond or more to turn on. The Class A operation permits cleaner operation under the high-current slewing conditions that occur when transient audio signal are fed difficult loads. His amplifier is basically simple, as can be seen from the block diagram.

To celebrate the hundredth design posted to this website, and to fulfil the requests of many correspondents wanting an amplifier more powerful than the 25W MosFet, a 60 - 90W High Quality power amplifier design is presented here. Circuit topology is about the same of the above mentioned amplifier, but the extremely rugged IRFP240 and IRFP9240 MosFet devices are used as the output pair, and well renowned high voltage Motorola's transistors are employed in the preceding stages. The supply rails voltage was kept prudentially at the rather low value of + and - 40V. For those wishing to experiment, the supply rails voltage could be raised to + and - 50V maximum, allowing the amplifier to approach the 100W into 8 Ohm target.

A medium power amplifier that is characterized by a lot of good sound quality, but simultaneously is very simple in the construction. Him uses, enough time in my active loudspeakers. In his output stage exist the very good FET transistors, technology HEXFET, transistor which are controlled by voltage and no by current as the classically bipolar transistors. The circuit has symmetrical designing, resolving thus the harmonic distortion problem. All the transistors that are used in the circuit are simple and they exist in big clearings in the market. The pairs of differential amplifiers Q1-2 and Q3-4 should be matched between them and near the one in the other. Thus you can buy enough transistors of types BC550C and BC560C, and with a multimeter you match between them creating pairs with same characteristics, ensuring thus uniform behavior in the temperature changes etc.

Presented is 68 watts LM3886 Power Amplifier with the use of popular LM3886 amplifier integrated circuit. Amplifier should be fed by source symmetrical good filtered of + 34 and – 34 volts. R2 and L1 is a resistor of 10 ohms / 2watt coiled with 10 to 12 you exhale of enameled thread AWG 20. The circuit integrated lm3886 is a component easy of being found at the electronics stores, for that he is used in several projects of potency audio, some exist circuits with linked lm3886 in bridges for potencies of up to 150 watts. For most information on the assembly of that circuit, I suggest that sees the datasheet of the lm3886 in the site of the national semiconductors. With the information of the leaf of data you can adapt the circuit with lm3886 your needs.

LM3886 is a high-fidelity audio power amplifier IC capable of delivering 68W of continuous power using 4 Ohm speakers. LM3886 provides excellent S/N ratio of 92dB and above as well as extremely low total harmonic distortion over the audio spectrum. LM3886 comes equipped with Self Peak Instantaneous Temperature Protection Circuitry (SPiKE) that makes it a class above other discrete and hybrid amplifiers. SPiKe Protection makes LM3886 amplifier safe against problems like over voltage, under voltage, overloads, shorts to the supplies, thermal runaway, and temperature peaks.

Here's a Leach Amplifier based on 2SC5200 and 2SA1943 output power transistors that can provide up to 700W of power. The mechanical design is relatively simple, the transistors are placed on the two cooling profiles with a height of 66 mm, width 44mm, overall length 260mm. They are turned against each other Thus, from the cooling tunnel. Coolers are attaching the nylon backing which allows the assembly of transistors without washers, and thus better transfer of heat. DPS amplifier is at the top of the tunnel and the transistors are soldered from the bottom of PCB.

This project considers the development of a 70W Hi-Fi Power Amplifier for use as part of a Hi-Fi separates music system. The design is a fairly simple circuit topology, which is easy to understand and the author believes that the finished result sounds very nice indeed. The web posting is developed from an original design document available in pdf below. The detailed design issues are discussed in the pdf, while this posting discusses the more practical issues involved in producing the amp.

The following is a 70W amplifier based on a popular TDA7294 chip. Main technical characteristics of the amplifier are as follows: input resistance - 22 kOhm input voltage - 750 mV nominal output power at 4 ohms and THD 0.5% - 70 Watts Frequency Range - 20 ... 20000 Hz supply voltage - ± 27 V, quiescent current - 60 mA. The amplifier has a built-in thermal protection, and protection against overload and short circuit in the load. For "soft" switching amplifier is SA1. Switch can be powered from a bipolar unregulated power supply. Power AC Transformer - 250-A, the secondary winding should be designed to current than 5A.

My goal was to design a high-powered wide-bandwidth amplifier with the finest sound and to keep it simple but not too simple. I rejected single-ended (SE) designs because of their low power and limited bandwidth. I wanted to see if I could get similar sound quality perhaps better with an efficient push-pull design. And I wanted to do it my way.

The PGA2310 is a pretty neat chip. It's capable of attenuating a stereo source over a 127dB range (-95.5dB to +31.5dB) with 0.5dB steps. It has a maximum gain error of +/-0.05dB, and THD of 0.0004% at 1KHz. The sweet spot between THD and noise appears to be between 3V RMS and about 8V RMS. I thus put 6dB gain in the input buffer (an OPA2134), so that the full-scale input is around 4V RMS with my CD player (2V RMS full-scale output). I used signal relays to select the inputs. If I was doing it over, I'd probably use some Analog Devices SSM2404 FET switches. However, at the time I laid it out I didn't know about the SSM2404, so the relays will have to suffice.