Originally Posted by indigoimac
I wouldn't bother replacing the satellites on the z5500 -- I have the older z680 set and while the klipsch are marginally better the z5500 was a significant step up. Both z680 and z5500 are quality units for their time, but htib systems are seriously starting to endanger the rather costly z5500.
The z5500 is using a cheap full range Tang Band driver for the satellites and then they tuned the sub high to give it a one-note-wonder loud sounding bass.
The klipsch sats are 2-way with a horn tweeter that offers much lower levels of distortion. The sub is arguably a bit dry sounding (slow early roll-off), but at least you get to hear the individual notes...
I would have to agree with the recommendation to pick up an old used receiver for powering the sats.
As far as the subwoofer amp, keep in mind that all commercial subs have EQ built into the amps to allow for smaller enclosures that maintain higher efficiency at the higher frequencies. In other words, you're going to lose out on a lot of low frequency extension unless you tweak your amplifier correctly.
With that in mind, most of the plate amps will have a section where you can modify the "rumble" (highpass) filter to be a peaking highpass and provide the bass boost and protection below tuning that Klipsch originally did in the design. When I purchased several amps from Rythmik Audio a few years ago, they did the mod for me...not sure if they'd do it on a one-off or not, but it might be worth asking. If nothing else, they might be willing to tell you how to do it:http://www.rythmikaudio.com/amplifiers.html
I know at one point in the past there were datasheets with pre-calculated resistor values...maybe someone else knows where to find them again as I didn't find them after a quick search.