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View Full Version : Replace a built-in sub amp with a stand-alone?


Alan Hoyle
April 3rd 08, 09:57 PM
I have an old JBL 12" subwoofer that the amp/PSU have blown out on. A
friend reports that it would be around $100 for parts to fix, but he's
concerned about the repairs just blowing out again. He suggested it
might make sense to just rewire it to and bypass the built-in
electronics and just plug in an external amp.

I'd be driving it with the "subwoofer out" feed from my 5.1 receiver.

Is there any reason why this would be a bad idea?

-alan


--
Alan Hoyle - - http://www.alanhoyle.com/

Kalman Rubinson
April 4th 08, 01:23 AM
On 3 Apr 2008 20:57:24 GMT, Alan Hoyle > wrote:

>I have an old JBL 12" subwoofer that the amp/PSU have blown out on. A
>friend reports that it would be around $100 for parts to fix, but he's
>concerned about the repairs just blowing out again. He suggested it
>might make sense to just rewire it to and bypass the built-in
>electronics and just plug in an external amp.
>
>I'd be driving it with the "subwoofer out" feed from my 5.1 receiver.
>
>Is there any reason why this would be a bad idea?

Very possibly. The original amp may contain a custom EQ for the
woofer. Losing that will definitely have an impact on performance.

Kal

Mark D. Zacharias[_2_]
April 4th 08, 12:32 PM
"Alan Hoyle" > wrote in message
...
>I have an old JBL 12" subwoofer that the amp/PSU have blown out on. A
> friend reports that it would be around $100 for parts to fix, but he's
> concerned about the repairs just blowing out again. He suggested it
> might make sense to just rewire it to and bypass the built-in
> electronics and just plug in an external amp.
>
> I'd be driving it with the "subwoofer out" feed from my 5.1 receiver.
>
> Is there any reason why this would be a bad idea?
>
> -alan
>
>
> --
> Alan Hoyle - - http://www.alanhoyle.com/

Really ought to work just fine. You might lose a bit of flexibility in that
the amp or receiver (which you use to power the sub out from the 5.1
receiver) won't have a bass rolloff control, but you should be able to
compensate for this using the 5.1 units' turnover frequency menu and level
settings, or even using the bass control of the amp actually powering the
sub.

Practically any amp or receiver of 40 watts or greater per channel ought to
be suitable. Use only one amp channel unless the unit is bridgeable or a
monoblock. Won't hurt to let the other channel idle.

Mark Z.

GregS[_3_]
April 4th 08, 02:31 PM
In article >, Alan Hoyle > wrote:
>I have an old JBL 12" subwoofer that the amp/PSU have blown out on. A
>friend reports that it would be around $100 for parts to fix, but he's
>concerned about the repairs just blowing out again. He suggested it
>might make sense to just rewire it to and bypass the built-in
>electronics and just plug in an external amp.
>
>I'd be driving it with the "subwoofer out" feed from my 5.1 receiver.
>
>Is there any reason why this would be a bad idea?

Seems like $100 is too much. You can by modules from MCM or Parts Express
for a whole new amp.

greg