Mackie Thump 15A Amp problem

did you need to post this twice?


random stab in the dark, but it could be the capacitor bank has died, so is clipping early making said popping noises, or even simpler, you could be clipping the input through either having the input on mic instead of line level, or simply sending far too hot a signal from source and having the speaker level low - albeit unlikely if it is a recently developed fault and it hasn't been an issue in the past on the same setup?

Could be the zobel rc network, capacitor leakage. Most likley on the HF output.

*ignore*


Edited by mk2_ginger_biscuit69 - 30 January 2013 at 5:44pm

I don't like toying with things like this so am sending it off to AbleTronics for repair
thanks for the help though guys :)

hello, just come across this looking for something else.
i just bought a thump 15a cheap as a writeoff, for interest really. having spent a lot of time with it, i can add some experience. i can say that all of the above suggestions are reasonable but given what i have seen, the cause is probably mechanical failure in the circuits or wiring. the spade connectors to the drivers are barely hanging on and will become intermittent as the power rises. the pcb/component soldering is shocking, so expect dry joints. the unit i have mostly repaired had a tricky fault in that a solder pad of a xformer leg was not actually connected to the pcb track leading from it.
i have resoldered all joints possible now.  you might consider converting it to passive and throw the electronics away if that is where the fault is. as suggested above, you can separate the amp from the speakers to check each independently. repeat warning of exposed high voltages inside.

Short circuited LF driver, It shows as 1 ohm and so the amp pulses as it protects itself from the over current. The bass driver is a "close to the bottom of the range" eminence.