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.
