Fuse keeps blowing in B&W speakers

[soundNERD]

Hi,

I have a pair of B&W DM580 speakers, and just got a new amp for them. The amp is a Yamaha RX-V1300, which is a 6 channel surround amp. It puts out 600W, 100 per channel. My speakers can handle 150W.

For some reason, when the volume is at about -27 db or so, and a deep bass note hits, one speaker's fuse will blow. I replaced it with a new 2A 250V, just like the old one, and it blew again. The other speaker, which I checked also has a 2A 250V fuse, didn't blow either time. Thinking the amp was bad, I switched the speakers, and the same one that blew before did it again, yet the other speaker is still on the original fuse. This makes me think there is something wrong with the speaker, but I have no idea what, except for possibly a loose wire or a short somewhere?

Any ideas on how to fix what is happening would be greatly appreciated.

Thanks, Mike

[MadMax]

As you say it happens during bass notes I suspect that you may be clipping your amp, a 100 W amp will blow 150W speckers if over driven. check wiring around fuse as a hot connection will cause fuse to blow early, 2A x 250 volt = 500 w, lower voltage of use will reduce wattage of fuse but I wouldn't trust im to save my B&W's, also check with ohm meter and ear. hope this helps good luck Mark

[Jan Dupont]

Hello Mike

You say that you only got the problems with one of the speakers, and that you have tried switching the channels from your amp...
Your problem must is absolutely be in the speaker, where the fuse keeps blowing.
Did you have these speakers from new???
Are you using slow or fast fuses???

If you have purchaced the speakers used, then the problem could be, that the former owner had replaced a slow fuse with a fast fuse in the speaker thats fails...
Or that the fuse in the speaker that works has a benn replaced (from fast to slow, and that it is your amp that clips...

Do as Mark says. Check with a ohm meter.....

[JOE DIRT®]

I would also inspect the crossover board on that speaker and look for any signs of over heating or poor solder joints

[SkinnyBoy]

Originally posted by MadMax
2A x 250 volt = 500 w,

yes.... but no one is using 250 volts... lol

[soundNERD]

I bought them used, and I looked at both speakers fuses. They both have a fast blow fuse, since they both have just a strand of wire in the fuse.

I will check them with my multimeter and report back. What am I looking at when measuring ohms? Too high or too low of a value?

Yes, I did switch the speakers to make sure it isn't a bad amp, and the same speaker as before blew.

I couldn't hear any clipping when they blew, and I would think these speakers could go to louder volumes than they were to when the fuse blew.

How can I get to the crossover? There aren't any screws on it's metal plate. Do I have to remove the drivers?

Thanks, Mike

[5th element]

Originally posted by soundNERD
I bought them used, and I looked at both speakers fuses. They both have a fast blow fuse, since they both have just a strand of wire in the fuse.

This isnt so I have bought quite a lot of slow blow fuses and they all just have a strand of wire in the fuse. Unless you are refering to a strand as a cylinder of wire and not a piece of foil with a cross sec of a coupla mm. I have got some slow blow which look like litebulb fillaments buts thats completely differnt.

I just did a search for the speakers in question and I see what tou mean about cabinet access. WOuld it be possible to remove those white bands around the drivers, I bet if you can the screws would be hidden beneath. Alternatevly try gainin access from the input terminals.

How much are the drivers actually having to work to produce this "note" when the fuse blows? It does sound like there is a problem with one of the speakers. But is it possible that they are working around thier power limits anyway? Or can you advance the volume quite a bit more and the other speaker plays without any problem?

[SkinnyBoy]

swap the fuses....

[battradio]

The pair of B&W speakersI had would blow the GMA 2 fuse about once a week . Have you set the bass roll off of your receiver or the low end EQ If not raise the roll off and lower the bass bost EQ .Check to make sure the vioce coil is not rubbing on the offending speaker .The crossovers may have zenner diodes to protect the speakers , the one that blows the fuse my be operating normaly and the other may have an open zenner or the one that blows the fuse may be over heated .Do you have any test Equiptment ? .

[battradio]

The gma 2 fuse will blow at 32 watts of sustained music on an 8 ohm speaker .
A 3amp will bllow at 72 watts .
Mark