Possibly damaged subwoofer

[1aespinoza 10+ year member]

For some reason, I thought both coils read ~.6ohms, but reviewing the pics, one is at 1.3 and the other at .6 - not a good sign.

Yeah, bad reading. On another note, I too have a P7000s. I have it powering a set of Magnepan MGIIIa. Do you believe the ratings on that Yamaha? It states 750x2 @8 Ohms and 1100x2 @4 Ohms. I put a pair of 12s @8 Ohms each and it did not sound like 1500 watts.

 

[Dubizzle]

Hi again all
Thank you all guys for your inputs and suggestions I really appreciate it.
I was so depressed yesterday as I have already purchased it and I can't go back.
So I decided as I've nothing to lose to take it apart to end up my misery.

The surround thin gasket, magnet rubber cover and screws that you'll see where it goes in the next picture

Here you can see where the screws that holds the spiders ring, its very fine philips head and I had to use impact driver to unscrew them, but once they got removed I felt relief

I forgot to mention the the HAMR Surround removal was pretty easy, just maneuver your fingers from underneath and push gently, one small portion is unglued the rest of the surround comes out pretty easly.

After removing the screws I pried the spiders ring with flat head screw driver as the ring was glued

Then I desolder the double voice coils from the jumper block

 

[Dubizzle]

Then, The moment of truth:

 

[Dubizzle]

Thoughts and lessons learned

Although it was a bad experience, I've learned from it:

*Never buy second hand speaker without checking the voice coils impedance with digital multi meeter.

*if a speaker impedance reads 1 ohm difference lower or higher than the specs its bad and you should walk away no matter how tempting the offer is.

*The acceptable used speaker voice coil impedance differences from the factory values should not exceed 0.2 ohm ( check my monitor audio driver picture)

* Dual voice coils speakers individual coils EACH MUST Read the factory value for each one of them.

* Regardless of whats in between a speakers voice coils and the final connection terminals ( jumper, fuse etc.. ) the readings at the terminals must read the factory spec or by margin of 0.2 ohm close to it, Because this is how the speaker is intended to be used, ( you won't go and connect your amplifier cables on the spiders and let them bounce when the bass hit would you?

Correct me if I'm wrong guys.

 

[Dubizzle]

I hope this helps someone out there so they won't have to deal with what I've been through.

Wil hunt for new driver or pair of them next time for my project to pair it with the yamaha p7000s.

I'll post it when I finish my build.

 

[Dubizzle]

Yeah, bad reading. On another note, I too have a P7000s. I have it powering a set of Magnepan MGIIIa. Do you believe the ratings on that Yamaha? It states 750x2 @8 Ohms and 1100x2 @4 Ohms. I put a pair of 12s @8 Ohms each and it did not sound like 1500 watts.

Do you recommend using this amplifier as a subwoofer amplifier to drive a car subwoofer for home theater purposes ?

I've read many positive reviews of it.

 

[1aespinoza 10+ year member]

Do you recommend using this amplifier as a subwoofer amplifier to drive a car subwoofer for home theater purposes ?

I've read many positive reviews of it.

It should do just fine as long as impedance is observed.