It's kinda a Sunday morning these are my thoughts on Pro Amplifier's as I'm pretty sure I've made it to my Happy place as one chapter is closing and another is beginning and that would be the joy of Music. I think it's worthy and may help the newbies that discover the Infinity Brand. I know when I did my first search on the RSII's Audiokarma was the first website that came up. So Wednesday I bought an Crown XLS Drivecore Series II 1502 from a major chain because I wanted peace of mind the amp would be new, unused in any way. Specifically to handle the woofers on my new to me QLS-1 speakers. I moved everything around a bit and lost the MC-2105 and put the Emotiva XPA-2 Gen 2 on the top. The Crown is a 8-4-2 Ohm stable amp. So basically I have about a total of 1,275 watts of power to throw at the big boys. I'll just say it sounds like nothing I've ever heard and suits me perfectly, I'm loving everything. For the price the Crown spanks the Watkins woofers, I really pushed it hard and could barely get the second set of lights to go, the fan doesn't come on until it's needed and it's a great feature of this amp. I don't know how it works but at 7 pounds it's light as a feather. Another great feature if your getting older and the back is as well. It's not my first pro amp, I destroyed just about all the regular type amps I had trying to get my Kappa 8's to sing being somewhat budget minded, Eagle, Adcom, Carver, Emotiva, Onkyo and a few I'm forgetting. It wasn't until I brought in a QSC-GX5 that could finally drive the 8's with ease. As a matter of fact it was the first time I had to get off the gas peddle so to speak. I was using an MC C-26 with this setup and it sounded very good. So in a nutshell, don't be afraid to try a Pro amp, I'd take the Crown over QSC simply because of the fan feature. I think your choice of Pre- Amplifier has a lot to do with the shape / sound of your music. If your Infinity's are biampable let the pro amp do the heavy hitting. If you have deep pockets the sky's the limit, but for the budget minded like myself the pro amp is a great option !