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Converting Active Sub to passive ?

Audiolab 6000A Amplifier

bigron

Active Member
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May 19, 2013
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Hey Folks

Looking to learn something here.

Have an old JBL E250 Active SUB WOOFER that just went kaput on me. On opening it was revealed that the caps and the MOSFET have given away.
Being a 10 year old sub I am finding it extremely hard to find the exact or similar components. Hence I am thinking of bypassing the internal amplification and run it through external amp.
How exactly will this work ?
I run a sub out from my receiver/integrated into an external power/sub amp and then run line level inputs into the sub or connect the L/R speaker out from the power/sub amp directly to the left and right channels on the sub driver ?
Feed back would be appreciated.
 

hydrovac

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As you already diagnosed the amp is blown, can you check if the preamp section is functional?

Assuming it is, all you have to do is to get the signal out and connect it to an external amp of same power rating, and connect the output directly to the woofer terminals.

If you need to keep all the inputs intact, you may have to fix a pair of binding posts on the plate...

hope this helps.
 

ShaQ.Blogs

Active Member
Joined
Mar 4, 2011
Messages
615
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43
Location
Bangalore
Hey Folks

Looking to learn something here.

Have an old JBL E250 Active SUB WOOFER that just went kaput on me. On opening it was revealed that the caps and the MOSFET have given away.
Being a 10 year old sub I am finding it extremely hard to find the exact or similar components. Hence I am thinking of bypassing the internal amplification and run it through external amp.
How exactly will this work ?
I run a sub out from my receiver/integrated into an external power/sub amp and then run line level inputs into the sub or connect the L/R speaker out from the power/sub amp directly to the left and right channels on the sub driver ?
Feed back would be appreciated.
Yup, you will need to Connect the pre-amp sub out from the receiver to the external sub amplifier's input. Then, Connect the external amp speaker outputs to the subwoofer driver.
The sub driver *does not* have a L/R channel. It has one driver with +/- terminals. So you will require just one output from the external amp.

The sub looks like it dosent require too much power.
Crown XLS series is a pretty good one to go with. You can also check Behringer. These amps start probably with 1000W, which might be too much.
But, if you are buying a new one, you might as well keep it future proof. Tomorrow, you could easily build yourself 2 kickass subwoofers yourself and cost you around 30K.

Ensure you power it correctly. You may not find an amp that's a perfect fit. So you will need to be a little careful with the gain.
Check out what the driver is and its specs.
 
Last edited:

bigron

Active Member
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May 19, 2013
Messages
181
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Location
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Thank you Shaq.Blogs.
You made it easy to understand.
I do have the xls 2000 on my list however I came across the DAYTON AUDIO SA1000 sub amp rack mountable.
Do you think it shall get the job done ? The gain, crossover and filter settings have to be done at the power amp level ?
 

ShaQ.Blogs

Active Member
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Messages
615
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Location
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While the dayton might be good, I am sceptical that it can beat the build quality of Crown XLS or even some of Behringer amps.
 
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