Had the surround sound going - a must for this video

There are 2 or 3 shuttle launches with the deep & loud sounds from the rockets.
Towards the end, during one of the launches, there was a click, and the deep bass went. Clearly the sub-woofer was no longer doing its stuff. Checked and found the internal T 4.0A fuse had blown. The mains fuse is fine.
I haven't got a spare so will need to get one.
Question. Why might it have blown?
All the speakers are Bowers & Wilkins, the sub-woofer is a Bowers & Wilkins ASW608. The amplifier is a 14-year old faithful, it's specification shows that in surround mode, only channel driven, front power output is 65W+65W; centre power output is 65W; rear power output is 65W+65W. All at 8 ohms. There's no specific power output given for the sub-woofer - nor would I expect one as it's merely a signal that the sub-woofer takes and amplifies accordingly, though I can set a level on each channel, including the sub-woofer channel. As I don't have a centre speaker that output is disabled.
Could I have overloaded the sub-woofer?

Any thoughts or comments would be appreciated.
[Edit: The old, blown, fuse is ceramic; a Maplin's replacement is glass, is that significant?]
Tony
We have more and more laws, and less and less enforcement
We have more and more laws, and less and less enforcement
Edited by cheshire_man (Tue 31-Dec-13 23:30:02)