Bass amp head trips power at switch on

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Hi all,

My bass amp head sometimes trips the power when I first switch it on. This only happens at one venue in particular, and it really gets on the sound engineers nerves!

Just wondering if there's anyway I can modify the amp to stop it doing this. The amp in question is a Behringer BX4500H. I've read in other places on the net that other users of this amp have experienced the same problem.

Any info or suggestions would be most welcome.

Cheers,
Gaz.
 
Presumably these venues are using MCB's instead of fuses? - MCB's are really too sensitive, we had to take them out at work and refit fuse holders.

But that's obviously not a help for your problem :D

What you could do is fit a slow start circuit in the amp, these used to be fairly common in big amplifiers, particularly with toroidal transformers - if your is toroidal?.

Essentially you wire a high wattage wirewound resistor in series with the mains transformer primary - this then limits the input surge to the transformer - after a couple of seconds a timer circuit shorts the resistor out, using either a relay or a triac. This drastically reduces the surge when you plug it in - and should cure your problem.

Have a look here for a more detailed explaination, and suitable circuits.

http://sound.westhost.com/project39.htm
 
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