Several questions. late as usual.
James Wendell said:
<font color='#000000'>I inherited an unpowered subwoofer from my son. It is for home use. I have a dolby audio system with a subwoofer preamp output. Without spending a lot of money I would like to power the subwoofer. Any suggestions? Can I obtain an amplifer (new or used) for about $100?</font>
First off, NAD makes great power amps. Powerful, stable and built like a brick outhouse. You bought a good one.
But, it might not have been the best solution for this application.
Unless you can control the output to match it to the rest ofthe system from the receiver, you might have been better off had you picked up an amp with level controls. As you are finding out, powered subs all have the ability to "match" their gain to the rest of the system.
Also, when bridging an amp, it will "See" the speaker impedance as one half of what it is. That is to say that if tou hook it up to one side of the subwoofer, it will see that 6 ohm impedance and 3 ohms.
Now, I'm sure the temptation will be strong to run that bridged output to both channels of tha sub which, in essense, is connecting both sides of the speaker in parallel. This wil lresult in a spealer impedance of 3 ohms.
Now, connecting a three ohm speaker load to a bridged amp, which will see the load as half that, will have it working into a 1.5 ohm load. That's really pushing you're luck.
IMNSHO, the perfect solution for you would have been one of those plate amps from parts express. They have all the flexibility needed to match any speaker/enclosure to any system. Level, crossover, phase, etc...
FWIW, I have one of these subs. I bought from DAK in 1990 or so for $150. ITwas OK in it's day but, on the whole, modern subs will blow it out of the water. Check out the Dayton subwoofers at parts express before investing too much money.
(I know this is an old thread. Since it was revived, I figured I should add a little perspective.)
