hi,
last night when i turn on my emotiva xpa-2 gen 2 power amp from standby position, i heard a loud popping sound on the right speaker. now the right woofer is dead but the tweeter is still playing music. i switched the woofers from right to left and it's positive that it's no longer working 🙁
it's a big amp rated 300 wpc for my diy 2-way speakers using scanspeak 15w/8530k00.
so what happened ? soft start circuit goes bad on the right channel ?
any idea what should i do next ?
last night when i turn on my emotiva xpa-2 gen 2 power amp from standby position, i heard a loud popping sound on the right speaker. now the right woofer is dead but the tweeter is still playing music. i switched the woofers from right to left and it's positive that it's no longer working 🙁
it's a big amp rated 300 wpc for my diy 2-way speakers using scanspeak 15w/8530k00.
so what happened ? soft start circuit goes bad on the right channel ?
any idea what should i do next ?
Do I read this correctly; you have a 300Watt per channel amplifier and feed 15Watt speakers with it?
Measure DC offset of right amplifier channel and voice coil resistance of dead woofer, also inspect woofer visually.
There are two possibilities for what might have happened:
1. There was a big transient on the output becase for some reason muting did not work as expected, possibly a stuck protection relay or bad electrolytic. This may have been too much for the voice coil wire on the poor woofer. Could be fixable if you find the break and feel confident soldering very thin enamelled wire.
2. The loud pop was an indication of major DC offset on the amplifier channel, indicating a defect in the amplifier. This then proceeded to cook the poor voice coil in the woofer, which in this case would probably be a total loss (though I see it isn't the cheapest part, so having it rewound might still be worth it).
There are two possibilities for what might have happened:
1. There was a big transient on the output becase for some reason muting did not work as expected, possibly a stuck protection relay or bad electrolytic. This may have been too much for the voice coil wire on the poor woofer. Could be fixable if you find the break and feel confident soldering very thin enamelled wire.
2. The loud pop was an indication of major DC offset on the amplifier channel, indicating a defect in the amplifier. This then proceeded to cook the poor voice coil in the woofer, which in this case would probably be a total loss (though I see it isn't the cheapest part, so having it rewound might still be worth it).
Looking at photos on the net, it looks like there is no loudspeaker protection relay so any issues with DC on the speaker line, the bass unit will fry.
thanks for the help. i think it will be a while until i get a reliable DMM. or maybe i can get a pro to my house to fix it. this thing is heavy.
That's the model number of the driver. The "15w" is not a power rating. It's a 15cm (wide) driver, thus the 15w/... nomenclature.
How soon after the turn-on "pop" did you turn off the amplifier?
Was there a burning smell? Can you smell a burned smell if you put your nose up to the driver now? Can you move the cone in if you push on it?
The "W" stands for 'woofer' btw.
The Scanspeak Scanspeak 15W/8530K-00 got a 38mm voice coil wich means they can withstand the power for a short while. It is more likely they got killed by the impact of the VC on the back pole plate. No higher rated woofer of that size would have made a difference there. Even almost none of any protections would have cought that.
That should not be a problem, unless there's a malfuntion in the system, or the listener suffer from alcohol-induced poor hearing.
Most dead speakers have been killed by underpowered amps.
Johan-Kr
i think it's about 1-2 minutes after i notice there's no sound on right woofer. i don't smell any smoke at all. touching the cone i feel there's no different between a healthy and damaged one.
My suspicion (also suggested by others) is that the fault likely put the full DC rail voltage on the output. The will cause the cone to violently smash to one limit of its mechanical travel, and this can rip the voice coil wire right off of its connection. It would be relatively easy to check this using a 9V battery. Disconnect the speaker leads from the amp and touch them to the battery terminals (keep leads connected to speaker on the other end!). You should see the cone move if it still has an electrical connection. If there is no movement of the cone when the battery is connected and disconnected it is likely that one of the leads from the connection terminal to the voice coil is broken. There is a slim chance that you can repair it, but you might just buy a new woofer and replace it, and then get your amp fixed.
you are right. i brought my dead woofer along with my amp to local repairman yesterday. the lead wire of the positive terminal lost its connection to voice coil although not visible visually. he fixed it and now it's singing again using my old mini hifi as an amp.
my amp probably will need some replacement parts but i'm gonna buy some stuff at mouser anyway so it won't be a problem. i can say i'm smiling like a horse today 😀
http://i65.tinypic.com/14e5dev.jpg
my amp probably will need some replacement parts but i'm gonna buy some stuff at mouser anyway so it won't be a problem. i can say i'm smiling like a horse today 😀
http://i65.tinypic.com/14e5dev.jpg
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actually i got it for 799$ on a summer sale couple years ago. still using linear power supply with big toroid unlike new gen.
It might be wise to add a safety protection relay board ( with it's own supply) outside the amp to ensure the next thump will not kill your speaker permanently. Those drivers are far more expensive than a dc protection relay board! Better to be safe than sorry.
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