The famous SGS-THOMSON ST Microelectronics has introduced a Hi-Fi DMOS high-power amplifier circuit TDA7294, its sound great taste bile, which due to its internal circuit from input to output are field-effect devices, rounded sound Mild, delicate Rounuan.
However, with its assembly amplifier, only TDA7294 single-output power is only 70 W, BTL access law is 100 W from top to bottom, do not feel that power cushion. The author several tests, used to promote TDA7294-level, direct-drive one to four pairs of high-power transistor parallel, the output of strong currents, the power output of 400 W (mono), and the circuit is simple and no need to debug that can reliably work Basically, the IC has maintained a sound and performance.
Ruzuo The figure below shows, R6 for the feedback resistor, the author of the value in debugging 22 k Ω more appropriate, R6 also decided this circuit gain, the gain value will increase.
Quiescent current depends on the power of R7, R8, when its value in the following 10 k Ω, the circuit will be in a Group A state of quiescent current adjustable to 100 mA ~ 2A, the author from 30 k Ω, the circuit works in Group B and fairly stable, power of With no radiator, in 2 / 3 the volume, to promote 10-inch speaker and 10 minutes later, the power does not feel that hot, thick sound quite strong.The author of the trial of the power of T1, T2, had used A1943/C5200, K1530/J201, A1302/C3281, which K1530/J201 the best sound quality, particularly soft Naiting. A map of the parameters, the output power of 200 W, in Group B work, with a small heat sink (I use 14 cm × 5cm × 3cm) to meet their cooling needs. Commissioning of the circuit without a ring box.