Tag Archive: Power amplifier

 Among the final amplifier we called. Regional Power Amp, will it work on several well-known as Class A, Class B, Class AB etc. Each class of the above, to honor the Class A was superior to the sound quality. best. However, class A power output to a low of 20 percent compared with a loss of power or the power consumption of about 5 times the power output. Therefore, the problem of heat Although it has not paid any audio. But anyway, despite the low-watt power, it also provides crystal clear sound quality than Class B and Class AB.

      Principles of integrated amplifier class A is IC1 – NE5532 to extend signal input through the C1 to increase 15-fold. The signal output from the pin 1, signal hemisphere positive through C2 to access Q1-BD139 and Q3-2N3055. is powered by Darling ton, amplifiers and signal the intensification of the negative side of C3 through the amplifier with the Q2-BD140 and Q4-MJ2955. This is the Darling ton, too.

Then the output signal from the positive side of the pin E of the Q3 and the negative side of the pin out of the E in Q4 through R10 and R11, to prevent short circuits and then output to the speakers. This will power up to 5 watts. The D1-D4 acts as a rectifier in the DC bias for Q1 and Q2. And VR1 is adjusted to a constant current bias is at work. The Q1-Q4 will be attached sheet cooled, Q3 and Q4, especially the thermal plate must be large. Because the circuit has high energy loss.

The TDA7293 has a bewildering number of options, even allowing you to add a second power stage (in another IC) in parallel with the main one. This improves power into low impedance loads, but is a rather expensive way to get a relatively small power increase. It also features muting and standby functions, although I’ve elected not to use these.

The schematic is shown in Figure 1, and is based on the PCB version. All unnecessary functions have been disabled, so it functions as a perfectly normal power amplifier. While the board is designed to take two TDA7293 ICs, it can naturally be operated with only one, and the PCB is small enough so that this is not an inconvenience. A LED is included to indicate that power is available, and because of the low current this will typically be a high brightness type.

The IC has been shown in the same format that’s shown in the data sheet, but has been cleaned up for publication here. Since there are two amps on the board, there are two of most of the things shown, other than the power supply bypass caps and LED “Power Good” indicator. These ICs are extremely reliable (as are most power amp ICs), and to reduce the PCB size as much as possible, fuse clips and fuses have not been included. Instead, there are fusible tracks on the board that will fail if there is a catastrophic fault. While this is not an extremely reliable fuse, the purpose is to prevent power transformer failure, not to protect the amplifiers or PCB.

I normally use a gain of 23 (27dB) for all amplifiers, and the TDA7293 is specified for a minimum gain of 26dB, below which it may oscillate. Although this is only a small margin, tests so far indicate that the amp is completely stable. If you wish, you may increase the gain to 28 (29dB) to give a bit more safety margin. To do this, just change the input and feedback resistors (R3A/B and R4A/B) from 22k to 27k.

The circuit is conventional, and is very simple because all additional internal functions are unused. The LED is optional, and if you don’t think you’ll need it, it may be omitted, along with series resistor R3. All connections can be made with plugs and sockets, or hard wired. In most cases, I expect that hard wiring will be the most common, as the connectors are a pain to wire, and add unnecessary cost as well as reduce reliability.

The TDA7293 specifications might lead you to believe that it can use supply voltages of up to ±50V. With zero input signal (and therefore no output) it might, but I don’t recommend anything greater than ±35V if 4 ohm loads are expected, although ±42V will be fine if you can provide good heatsinking. In general, the lower supply voltage is more than acceptable for 99% of all applications, and higher voltages should not be used unless there is no choice. Naturally, if you can afford to lose a few ICs to experiments, then go for the 42V supplies (obtained from a 30+30V transformer).

This amp can also be bridged, using the Project 87 balanced transmitter board. You can expect about 150W into 8 ohms from a +/-35V supply. It cannot be bridged into 4 ohms, as the effective impedance on each amplifier is too low.

Typically audio amplifier stereo amplifier to a two amplifier. And if a mono amplifier is a single speaker. However this circuit command be present extended to the mono two loudspeaker.But not a equivalence or else serialization access.This makes it needless impedance of the speaker has altered.But will remain to utilize the spokeswoman as a replacement for of the resistance – Collection Peter (RC) of the transistor.The circuit can be alive prolonged to 2 loudspeaker itself. A1015

What time raising the power supply circuit and the audio to input. the audio sign coupling to through the C1 and R1 to increase with the Q1.Which Q1 serves like the Regional Pre amp amplifier to power up to a one point.already conveyance it to Q2.Which Q2 is connected to emitter follower circuit.be active as a driver amplifier intimate section from the pre amp section provides added power to drive the Q3 perform. and Q3 motivation provide while a Regional Power amp amplifier output to the spokeswoman.The opinion of the audio intimate through the VR1 and R2 to enter the pin B of Q2.To control the stability of working instead of well brought-up.This circuit is an output of 40 milliwatts watts of distortion of the gesture rate is by the side of 0.1 percent.And frequency response from 15 Hz – 200 kHz.


Circuit of power amplifiers with power output of 450 watts mono , amplifiers are also frequently used in the amplifier a high-power amplifier, which used in an event, in the field and the placed closed. Because this amplifier suitable for the woofer, fullrange speaker, and can also be fixed for the subwoofer speaker. To further strengthen and maximize the amplifier ,its power supply circuit also must be accurate, for electrolytic capacitors in power supply ,voltage capacitors use 80V or more, and a capcity 20000uF upwards, so when the bass amplifier is high , the voltage is not lot of experience dropping. Diode bridge use a minimum of 35A, or adjust the current input voltage. If the power supply has fulfilled the desire, the supply to the power amplifier.


In the buffer circuit uses PNP transistor A1266 / A564 / A733 /A1015 / A798 and NPN with MJE340.To the driver circuit using PNP transistor MJE350 and MJE350. For the final amplifier circuit use two set 2SC2922 and 2SA1216. Use a quality sanken transistor to maximize quality sound output.