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John Bowers Active 1 loudspeakers

I have owned and enjoyed a pair of John Bowers Active 1 loudspeakers since 1990. Recently, and for the first time, a fuse blew on power up. The fuse is a Belling-Lee 10A, and it is apparently the original fuse. (Same fuse in the other speaker.) In looking for a replacement, I have been asked "fast blow or slow blow?". There is no such designation on the fuse, and the original Service and Parts Manual does not specify. Can anyone help with this question?

Re: John Bowers Active 1 loudspeakers

The fuses for mains are generally time lag ("slow blow"). Note that 10A
is used for 110 volts and 5A are required for 220 volts ac.

You should check that the amp is fine. The fuse may have blown because
of age but you may also have a short inside.

The old trick af connecting a mains light bulb IN SERIES with one of the
mains leads may help if you don't have access to an electronic repair

If the bulb lights up strongly after switch on (new fuse already inserted)
you have a short inside, but current is limited. Now is the point to visit an

If the bulb remains dark, the amp and supply are fine or safe at least.

The amps must be overhauled after long term use, because most small
electrolytics suffer from internal heating. The same is true for solder joints
especially on the crossover board.

Re: John Bowers Active 1 loudspeakers

Many thanks for your comments. I had also been in contact with B&W Support, who had recommended a fast-blow fuse. The replacement fuse arrived yesterday and last night I gave it a try. As I feared, it appears that I have a larger problem than just a blown fuse. The new fuse blew immediately on power up. I guess I could try a slow-blow fuse, but I don't imagine that would make the difference. It's probably a short or other such problem, so now I'm on the hunt for a qualified repair shop. Any recommendations are welcome. I'm located in South Carolina.

Thanks again!

Re: John Bowers Active 1 loudspeakers

It is essential to use a slow fuse, especially with this toroidal transformer.
The "Support" did not read the manual and gave wrong advice. A fast
fuse is only adequate if you want to turn on slowly with a variac. My
advice is still valid in every respect.

PS I receive no notification for any additions, so perhaps PM me.