Re: Need Nexo PS-10 mains / LS600 subs advice.
Bob,
The output of the amplifier in a NEXO system goes two places, to the loudspeaker loads AND to the processor. This is how the processor is able to monitor the loudspeakers, it has nothing at all to do with the amplifiers. Normally, the processor and amplifier live in the same rack together and remain wired up together all the time.
You should note, if you are using the analog processors, you MUST use amplifiers with 26dB gain. However, if you are using the NX242 or NX241, you can use pretty much any amplifier and dial in the settings for that amp.
If you are looking to just get the PS-10's only for now, I would look into finding an Analog controller, then add whatever amp you like that has 26dB gain. However, if you are thinking about adding the subwoofer in the future, I know NEXO used to make an integrated analog controller and amplifier for the PS-10's with mono sub specifically (they also had one for the PS-8's with mono sub). But, with the advent of the NEXO 4x4 and 4x1 amplifiers, they may have canned those amps and you may have a tough time finding something like that used.
If I were doing what you are doing, I would probably try to find a used NX241 or NX242 and buy a new Crest Audio Pro 9200 power amplifier. Then, when you want to add NEXO subs later, you can just add another Pro 9200 for sub duty. In the mean time, you can run your L & R into your inputs on your rack for the NEXO processor, and use a Y cable on the main L & R for your powered sub. Or, of course, if you are doing Sub on Aux, you can just connect your powered subs to that.
Whatever you do, you absolutely NEED to set up your processors correctly. Too many people think they can "out-smart" the system by setting the processors differently than the recommended settings. This is a great way to break things and make the rig not sound as good as it possibly can. Those french guys are kind of weird but if you follow the directions, the NEXO stuff sounds totally amazing. I think they are the best sounding passive pro loudspeakers I've ever heard.