Again I've blown this amp twice now. (hand to forehead) This time not due to low ohm load but I switched an inductor in the passive xo, music was stopped amp on, and a strange thing happened.
The circuit in question was a split to two drivers a 15" SBa and a 12" B&C pro. each having an LR2 XO and a LCR filter. When I disconnected the inductor from the 15" circ. there was a static build up sound and then a low end 'hwomh' then white noise out of the 12". I've since tested it on commercial speakers and I get white noise out of both channels.
For fun anybody have a guess as to what happened? Since I don't know amps very well and before I blindly send it in for repairs is there any chance this could be a cheap fix?
The circuit in question was a split to two drivers a 15" SBa and a 12" B&C pro. each having an LR2 XO and a LCR filter. When I disconnected the inductor from the 15" circ. there was a static build up sound and then a low end 'hwomh' then white noise out of the 12". I've since tested it on commercial speakers and I get white noise out of both channels.
For fun anybody have a guess as to what happened? Since I don't know amps very well and before I blindly send it in for repairs is there any chance this could be a cheap fix?
Playing around with disconnecting a powered up inductor = high voltage transients. Its a very good way to destroy a motor drive circuit for instance. This inductor must have been a big metal-cored one, not air-cored I suggest - able to store a lot of energy and turn it into inductive kick-back and arcing.
If you're lucky you only blew the output devices, but the presence of noise suggests a more complex failure.
BTW you could easily have electrocuted yourself, lethal voltages can be generated by big inductors, and big amps have high enough voltages to shock anyway - power down before reconnecting.
If you're lucky you only blew the output devices, but the presence of noise suggests a more complex failure.
BTW you could easily have electrocuted yourself, lethal voltages can be generated by big inductors, and big amps have high enough voltages to shock anyway - power down before reconnecting.
Mark good guess it was a 12 mH iron core. I guess I wasn’t aware that much was going on at idle. I’ve seen other speaker builders (Wilson) test inductors on the fly, music playing even... hot swapping them to hear the difference. Sounds like white noise is bad news. Well thanks for the insights
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