2 systems one set of speakers?????

Hello All I have a question that maybe someone out there can help me with. I have a pre-amp, amp, cd player set up by its self. and I also have a receiver and another cd player that sound really good together for rock cds and the cds that don't sound as well on the pre-amp set up. Is there away I can use the 2 systems through one set of speakers?? So I can play the pre-amp set up and then switch to the receiver set up on the same speakers. Can I run 2 sets of speaker wires to the same set of speakers?? or will this damage one or the other. is there anyway or some thing I can do? I'm new at this so please someone help THnaks
I would think for the cost of this elaborate set up that you could easily replace it with something that sounds better then either.
I'm not sure about running 2 sets of cable to the same speakers, perhaps someone else will comment on that. I know of one way you can use both sets through the same speakers, if your amp can take both a balanced and an unbalanced signal. Route your receiver into the single-ended inpur on the amp, and use balanced connections from your preamp. This will only work if your amp has both kinds of inputs, and your preamp can go balanced out. If it can, just make sure you never have both running hot at once. BTW, just for kicks, have you tried running the CD player you like for rock directly into the preamp? If it's the player you like, and not really the receiver, that would make life much easier, as you can have both players in separate inputs on that preamp.
DO NOT run two sets of speaker wires to one set of speakers...you would essentially be connecting the outputs of the two amplifiers together, which is BAD. The only safe way to do this is to have some type of switching box that isolates the two amps. Such a device isn't very common, unfortunately...I'm not sure where you'd find one. A better solution would be to use two sets of speaker cable terminated with banana plugs, and just swap the connections to the speakers.
You can (and should) use a speaker switch in this situation. Connecting your separate amp and the receiver to the same speakers would connect the outputs of the two amps together, and result in damage to one or both units. Quality speaker switches are readily available for little money. Though they are normally used to switch one amp between two sets of speakers, there is no reason they could not be hooked up in reverse by connecting your amps to the speaker-outs and your speakers to the amp-in on the switch.
Niles Audio (www.nilesaudio.com) makes a device to switch between 2 amps and 1 set of speakers. It's the DPS-1, Niles stock # FG00003. I think I've seen some other more professional switches, such as the ones some stereo shops use to switch between systems. Good luck.
Check the Bryston website. I think they make switch boxes for installations similar to this also. :~) Doug
If your preamp has tape input, you can plug in your receiver righ there and run it through your power amp.
There are also A/B speaker switches that you can use in reverse order selecting your power amp instead of speakers which are still probably available at RadioShack.
The Niles unit mentioned above is a good choice for this application.