Originally Posted by eljr
Just confirm that I need an amp with a sub out in order to really make a difference. Correct?
No. Not IMO and IME even remotely true in your situation.
It looks like this document has escaped many people's attention:http://nadelectronics.com/download.p...guage%20Manual
"...the preamplifer section can be separated from the power amplifi er for easy upgrades or adding ancillary equipment."
First off, the worst
way to implement a sub is to just add a powered sub to your system, but even just doing this can provide a major sound quality advantage. The sub extends the bass range of your system but does not take a load off of your existing speakers. Still potentially a strong audible benefit.
This call depends on what your upper range speakers are. Quick scan of the thread does not seem to reveal that important fact.
Secondly, since you seem to have a separateable preamp and power amp, in your integrated amp you are free to implement your sub the best possible way, which involves having a separate power amp for your sub *and* electrically splitting the signal so that your upper range speakers don't see the deep bass that your sub is there to handle.
Your functionally separate preamp and power amp section allow you to take the signal wires that come out of your preamp section and plug them into the inputs of an electronic crossover, and then plug the signal wires going to your existing power amp section, and plug them into the outputs of the electronic crossover.
Right now those preamp-to-power-amp wires are short little jumpers, per pictures of your integrated amp.
The electronic crossover may be part of the sub which would then have its own power amp, or it may be a separate component that you buy.
You've got options, IME good options!