Expert: Cleggsan - 8/31/2009

Question
Good Day...Just came home with the amp of my dreams and when I turned it on it nearly fried the speakers of my dreams...As soon as I power it up...the woofers come way out of the enclosure accompanied by a loud pop...then they retreat slowly back to home posituion...Any ideas...Thank you

Answer
Not uncommon.  This is caused by dc coupling.  When the amp is turned on it gets a dc jolt from the power supplies that causes a dc rush of current through the voice coils of the speakers.  It should not be harmful to the speakers unless the power rating of the amp is much greater than the power handling of the speaker systems.  The greatest danger is to your ears and your ego.

It can also be caused by a leaky coupling capacitor in the preamp output or input on the Luxman.

It is possible this phenomenon will go away after a few ON/OFF cycles - which will get all the caps charged up and diminish the leakage factor.

In the worst case you may have to replace a capacitor or two.  

Check and see if there is a DC switch on the amp; some of the older models had such a switch which allows for direct coupling vs cap at the input.  Try it in either position; one may be better than the other.

Let me know if there is more you need.
C