Hooking everything up for the first time

It looks like to me your receiver (the Onkyo) doesn't have pre-outs for most of the channels. If your intent was to add more or better power to your various speakers, you probably can't do that with that receiver. In order to run to a power amplifier, the pre-amp or receiver needs to have "pre-outs" associated with the channels that you're trying to run to the power amp. Once you have the "pre-outs" on the receiver/pre-amp, you use RCA cables like has been previously mentioned.

Sorry the news is probably not in line with what you were hoping, but I think you might have a bit of a case of "You can't get there from here."

This is such miserable news! I've waited months to have this stuff shipped down to Mexico via friends because other shipping methods aren't reliable.

It's going to be months to ship it back again and get the right thing. Maybe Amazon will still take it back...

Jlind325is Paraneer Lindstad - despite the grim news, you guys saved me from making a(nother) dumb move here - thanks a lot!
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The first thing I couldn't understand when researching this was why no one seems to make a reasonably priced pre-amp ONLY. Manufacturers would be saving by not including amplification and customers could then afford to step to decent sound.

People on this forum said, 'Get any receiver and forget about the amplification included' but I guess they forgot to mention what a novice might not know.

Does anyone have a suggestion for the right thing to get, does anyone want this Onkyo - you know I haven't plugged it in!

Your welcome Rev. Yes, you are right about no reasonably priced pre-pros. When you think it about it, they are basically AVR's without internal amps. They should be cheaper, right. NOT! Kind of makes you wonder how much it actually costs the manufacturer to throw in built-in amps???

The talk on internet forums about any AVR will do is correct except for one key feature - any AVR with PRE-OUTS! About the cheapest current model I can think of is the Yamaha RXV 773. They go about $800 usd. You might want to try the used market. Just make sure it is a newer model that has HDMI and will decode the new lossless audio formats. Prior to these lossless formats, it seemed most AVR's, even the entry level models, had pre-outs. Now this feature seems to be found on the $800 models and up. Things change. Good luck with your problem.