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Possible impedance matching issue with subwoofer?

Ok, many of us know about the importance of impedance matching with gear. I guess I have not thought enough about this with my sub. My sub is a powered sub like many are. It has it's own built in plate amp. The input impedance of these plate amps/powered subs is often quite low. Mine and many are 20k ohms or so. My preamp has an output impedance of 5k ohms, making for a possible poor match with the sub if I use the 2nd outputs on my pre into the sub's RCA inputs. This is the way I now use the sub.

I suppose I could hook the sub up by going from my amp to the high level inputs on my sub? I could simply run a second set of speaker cables out from my amp to my 2 subs this way right? This would avoid the impedance issue with my pre. Am I thinking correctly?

I think my subs may be rolling off the deep bass because of the impedance issue?

The system sounds very good as is, just wondering if perhaps I am onto something I have missed with possible bass performance improvement.
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Showing 1 response by davehrab

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davehrab
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"My preamp has an output impedance of 5k ohms, making for a possible poor match with the sub (20K input Imp.) if I use the 2nd outputs on my pre into the sub's RCA inputs."

You can add a SS Buffer ... 1 to 1 gain amp ... to 2nd output on preamp to lower the preamp's output impedance to better match your sub's 20K input

The Buffer should not add any gain but lower the impedance of the preamp from 5k to less than 600 ohms

With a 5K output I would guess the pre is Tube .. how is match to main amp ??

"I suppose I could hook the sub up by going from my amp to the high level inputs on my sub?"

I wouldn't daisy chain if I didn't have to ... keep the main amp and speakers seperate

"I could simply run a second set of speaker cables out from my amp to my 2 subs this way right?"

Then the main amp would have to drive both the main speakers and two subs ... may be to much of a load to ask your amp to drive ...
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