Troubleshooting my Fried Nautilus NHTM1 Center Channel

[digitalman]

I have a NHTM1 center channel, it was hooked to a B&K reference 7250 Series II amp which has now shorted out and fried for the 3rd time.

the first time the amp fried and shit down it was connected to this NHTM1, I have always felt the the center never really sounded that good afterwards and think that something was damaged in it.
After getting the amp repaired I had it connected to my NSCM1 surround speaker testing and the amp blew again and sent electricity into the speaker and smoke came out of it. I had the amp repaired again, and the guy also took the kevlar mid driver and "repaired" it, I dont know what he did, the cone was seized up and couldn't move and now it moves, but pink noise doesnt sound the same now as it does in my other identical speakers. So i have this amp connected to my NHTM1 which doesnt sound that great to me anymore, slightly higher pitched and tinty sounding. then it seemed like all the bass went away from the center. So i turned off the amp and grabbed my old polk center to test with. About a minute later when i pulled the banana plugs from the speaker i felt that tingling sensation like i was being electrocuted and then when they came out and touched each other i got a big electric spark and pop sound. there was voltage going into the speaker even though the amp had been off for a minute.

I pulled the bass drivers out, they smell burnt and although the cones can physically move they produce no sound whatsoever, i tried the AA battery test as well as connected each to a power receiver and they both produce no sound. I plugged the top half connectors into a receiver and played some music and disconnected the bottom half of my 802 mains and played the same thing out of both and they sounded very similar so i think the tweeter and mid are not fried ( i was bi-amping)

these 2 woofers at $260 each to order from B&W. is it possible for them to be repaired? will they sound like they are supposed to if so? I also need to make sure the crossover is not damaged from the voltage somehow.

Thanks for any help

[TomScrut]

For that amount of money it may be worth researching if the HTM3S drivers will fit as they will be better and I presume a similar price. Other than that I can't really help though

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[Kevin P]

DC into the speakers will mostly harm the woofers, as the crossover blocks low frequencies and DC to the other drivers. The crossover choke in series with the woofer could be damaged as well. The coils overheat and could deform the assembly. The drivers would need to be reconed or replaced.

If the mid driver was damaged and "fixed," the coil could still be deformed if it wasn't replaced/reconed. That would affect the performance of the mid driver.

At this point it might be cheaper/easier to pick up a used NHTM1 instead of trying to repair your existing one.

Definitely get that amp fixed before connecting any speaker up to it again.

[dan87951]

Trash that amplifier! The htm3s drivers will not work in the htm1 -- different bolt pattern.