I've built the power amp shown at http://europa.spaceports.com/~fishbake/amp/ca100.htm
I keep blowing the TIP 142 transistor meaning it explodes. I've replaced it 3 times. It also has a heatsink attached as well as the other power transistors. Any ideas why? I double checked the pinout with the company and my wiring seems to be correct.
blowing transistors
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Egads, I would never contemplate an amp with that sort of power built like that.
OK, have you checked that the transistors are all isolated from the heatsink? The collector is usually also connected to the metal tab of the case. If the case of the TIP41 is connected to the case of the TIP142 (via a short through the heatsink typically) you will connect the base of the TIP142 to the positive rail. It will die in milliseconds.
OK, have you checked that the transistors are all isolated from the heatsink? The collector is usually also connected to the metal tab of the case. If the case of the TIP41 is connected to the case of the TIP142 (via a short through the heatsink typically) you will connect the base of the TIP142 to the positive rail. It will die in milliseconds.
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Under very limited occasions it can be acceptable to mount the transistor directly to the heatsink with no insulating washer, usually when there are huge amounts of power involved and the extra thermal resistance is a real problem. But then you need to ensure that the heat-sinks are all on insulated mountings, and it all gets really bad. This is the sort of thing you see in high power RF systems.
It sounds as if you have mounted the transistors without an insulating kit and now have a short through the heat-sinks. If all three transistors had their cases shorted they would simply short out the power supply, so it does sound as if there is a subset of possible shorts.
The TIP41 has a maximum collector to emitter voltage of 40 volts. This suggests that if the TIP142 has died big time that it may well take the TIP41 with it - perhaps not with an explosion, but enough to fry it internally.
This is a 150 watt amp - although it would appear to be a class B design, and thus will idle pretty cool, when run hard it will dissipate a lot of power. It will need a big heatsink.
My comment about the power and construction was all about the way it would appear to have been built on the cited web-site. That looked like an accident waiting to happen.
It sounds as if you have mounted the transistors without an insulating kit and now have a short through the heat-sinks. If all three transistors had their cases shorted they would simply short out the power supply, so it does sound as if there is a subset of possible shorts.
The TIP41 has a maximum collector to emitter voltage of 40 volts. This suggests that if the TIP142 has died big time that it may well take the TIP41 with it - perhaps not with an explosion, but enough to fry it internally.
This is a 150 watt amp - although it would appear to be a class B design, and thus will idle pretty cool, when run hard it will dissipate a lot of power. It will need a big heatsink.
My comment about the power and construction was all about the way it would appear to have been built on the cited web-site. That looked like an accident waiting to happen.
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