Hello, got this amp. Its a Fullrange class d. It uses a lot of tl074. Two channels are blown. I checked gate resistors and drivers, all are ok. Each channel use two p-Fets and two n-fets.
If i install new one, directly some of them short. No explosion, just short.
Any suggestions?
If i install new one, directly some of them short. No explosion, just short.
Any suggestions?
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So, i tried trough a limiter, and bias full down. Seems to be ok...but why they had been damaged???
Also what i dont understood, normaly all class a/b amps use transistors and no mosfets..
Limiter is 4 Ohm, the voltage drops from 12.5V to 6,4V. So a lot off curent
Also what i dont understood, normaly all class a/b amps use transistors and no mosfets..
Limiter is 4 Ohm, the voltage drops from 12.5V to 6,4V. So a lot off curent
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Sometimes the bias drifts and causes overheating.
Any time you replace the output transistors, start with the bias fully down (not always fully CCW).
FETs have been used in the output stages singe the 1980s.
You can generally tell switching amplifiers (class D, etc) from non-switching/linear amplifiers (class A, class AB, etc) by the components at the output transistors.
Linear amplifiers typically have a 0.1-0.3 ohm on each output transistor. Most switching amplifiers do not.
Switching amplifiers typically have a relatively large filter inductor and capacitor (shunting to ground) between the output transistors and the speaker terminals. Linear amplifiers do not. If there is an inductor in series with a linear type amplifier, it's small and very low in value. Any capacitor across the output of a linear amplifier will be in series with a resistor.
Any time you replace the output transistors, start with the bias fully down (not always fully CCW).
FETs have been used in the output stages singe the 1980s.
You can generally tell switching amplifiers (class D, etc) from non-switching/linear amplifiers (class A, class AB, etc) by the components at the output transistors.
Linear amplifiers typically have a 0.1-0.3 ohm on each output transistor. Most switching amplifiers do not.
Switching amplifiers typically have a relatively large filter inductor and capacitor (shunting to ground) between the output transistors and the speaker terminals. Linear amplifiers do not. If there is an inductor in series with a linear type amplifier, it's small and very low in value. Any capacitor across the output of a linear amplifier will be in series with a resistor.
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