I would do what footman suggests and, if you have another amp, try the speakers on that amp. That will help you to find out whether the problem is in the amp, speakers or both. You might try the reverse if you're a risk-taker (PL amp and other speakers) but if fuses keep blowing, that isn't good and if the amp is shorted, it might hurt the other speakers. I would try replacing both fuses at the same time (the one not blown might be almost gone) and check to be sure that there are no single wire strands from the speaker wires that are shorting out. If everything looks good though and the amp still blows fuses without apparent cause, then it looks bad. I lost a wonderful vintage Carver 400 WPC amp last summer to a lightning strike and the symptoms were similar. The outcome wasn't good....fried. Fortunately, however, the Vandersteen speakers came out OK.