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Ian Mackenzie
10-18-2004, 05:24 PM
I regret to inform the passing of on of my 2245 woofers last night.

The story.

For the past two days I had noticed a faint buzz and rattle when I turned off one of my power amps following the jig up of a make shift power supply to enable comparions with another amp.

At the time I figured thats odd, must be a dry solder joint, so I opened up the amp last night and checked everything after re soldering some joints.

I was confident enough that i did not check for any Dc offset and threw the on switch.

A loud hum of the full load current on the 12amp power supply came through the left woofer as it drew in a deep breathe then slowly let it out, then finally a small wimpering fart.

The woofer cone, quite warm to touch now and the cone locked tight. The negative wire to the driver board had finally broken off a copper buss bar, allowing the full positive swing of the supply rail via 6 80 amp mosfets followers into the 5.6 ohms DCR of the woofer.

Alas no speaker line fuse, but the 2245 took it all and then some.

Oh well, it was the shabby refoamed woofer I did previously so don't feel too badly.

Ian





:eek: :o

Robh3606
10-18-2004, 05:28 PM
That sucks!! Want us to keep an eye out for one?? Can you get a recone kit at home??

Rob:)

speakerdave
10-18-2004, 09:23 PM
Reminds me of the time I watched the smoke curl up from my AR3 woofers while trying out an ebay DC300A. I will never do that again!

David

Ian Mackenzie
10-19-2004, 03:48 AM
Thanks guys,

I think I can recone locally, about $600 if they have any stock..ooch.

I might think about some options when I recover from the shock

Ian:eek:

Chas
10-19-2004, 07:42 AM
Ian, you have my sincere condolences. Same thing happened to me this summer when one of my "utility" stereo power amps went full rail and I smoked a pair of Celestion SL-6s. At least they weren't JBL's:D

Dynacoman
10-19-2004, 09:17 AM
I smoked a pair of Celestion SL-6s. At least they weren't JBL's

Unfortunatly you never hear about Bose speakers getting full rail.
They would sound better then.;)

Jim

Ken Pachkowsky
10-19-2004, 10:15 AM
Since yesterday, I have developed anxiety when turning on all my amps!

Ian in all seriousness that is a bummer. Touch wood, its never happened to me and hope it never will.

Bose......haha...were bad.

Alex Lancaster
10-19-2004, 01:17 PM
Is that $600 US or AU?

johnaec
10-19-2004, 01:21 PM
I have a 2245H that was reconed at the JBL factory and has had one re-foam since by a JBL shop - $125 plus shipping if anyone's interested. In excellent shape, (always in a cabinet).

John

Ian Mackenzie
10-19-2004, 01:59 PM
Thankyou all for your feedback.

Yeah, its a bit weird, I had that short of preminition for a day or two before it happened that something was going to happen.

The day before I had a bird fly in around the house, it swooped on me while I was reading the forums:eek: . That was a sign.

These things come in three's so I am going to take a breather for a week or two.

I have'nt told my brother yet, he's had plenty of experience with a 700B going ape into his 2235's. I am sure he will be understanding.

I will drown my sorrows on the weekend and wait for Bo's timely Chime in (i'm on his ignore list at the moment I reackon).

regards

Ian:)

Ps there are little feathers all around my JBL Lab, The birdy is no more!!

doodlebug
10-27-2004, 01:58 PM
[QUOTE]Originally posted by Dynacoman
[B]Unfortunatly you never hear about Bose speakers getting full rail.
They would sound better then.;)

This happened to me when I worked in an audio store in the 70s to a pair of 901s. The then-new Bose 1801 power amp had just come out and we set one up and left it on all night. Came back the following morning to find the amp with blown line fuse and both 901s with *completely* immobilized cones. Discovered that both of the input opamps Bose used for 1st stage voltage amplifiers had a bad habit of latching on in one polarity or another occasionally. Bose thought they had caught up with most of the amps with that run of chips, too.

It was fun cutting all the cones out of 18 drivers to confirm for them what had happened.

Cheers,

David

Steve Gonzales
11-08-2004, 10:46 AM
I was just kind of surfing the forums and read your story, that's a drag!. On the other hand I have got to tell you I haven't laughed that hard in a LONG time!!!!!!, I am refering to your description, my god, that is FUNNY!!!

Ian Mackenzie
11-08-2004, 12:57 PM
I was just kind of surfing the forums and read your story, that's a drag!. On the other hand I have got to tell you I haven't laughed that hard in a LONG time!!!!!!, I am refering to your description, my god, that is FUNNY!!!
I seek therapy in doing this for the moment.

Ian

jarrods
11-09-2004, 01:10 AM
Hey Ian,

wow bad news on the burn out. i was worried about that with the ProSeries 3 amps I had, and the exra one i built up, so i retro-fitted some speaker protector circuits to offer some insurance. is a small card and two HD relays.

http://sound.westhost.com/project33.htm

i actually have 3 spare blank PCBs from this guy as i got half a dozen.

jarrod