How to share speakers without bypass?


I hope I am not the only one in this predicament. I am adding a separate two-channel system into the same room where my home theater lives. I would like to share the two front speakers between the two-channel amp and AV receiver. No, I cannot consider using a HT bypass (or pass through). The two-channel amp is tubed and would need to be powered on and warmed up (20 min). This is not a problem for us adults, but when our 8 year old (or the other kids that flood in) needs to watch a DVD 'NOW', well, you see the problem.

So, my options are:
(1) Buy some additional front speakers to keep everything separate. Only drawback is the speakers would have to be small (space limitations and wife). This means HT would suffer a bit; Merlins vs satellite speakers.

(2) Find a quality switcher that connects two amps to one pair of speakers. Don't know if this is possible and would not want my two-channel listening to suffer.

Or? Please help if any of you have pondered this.
jazzalot
Zoya, I would like to add to your suggestion, or theory. If you bi-wire in reverse, why would the amp and receiver be on at the same time? If they have to be on, why not put one in stand-by, mute or speaker off while the other is in use.

By doing this, you would avoid breaking the speaker wire.
Jazzalot
Yes, that's the one.
I also connect to this selector from receiver/amp using 12awg silver plated cable, and regular speaker cable out from it to speakers (Tara labs bi-wire, but twisted as one). I don't think I hear any reduction in sound quality.

Drawback ? Yes, the two buttons for A/B can be turned on at the same time, my wife mistakenly did it couple times and both system didn't get any problem ... yet. I had to remind her more than once, release the down button first, then push the other later.
The soluttion is relativly simple if you don't mind giving up the absolutes in performance with the main system. Power 2 DPDT relays from the switched outlet on your surround receiver. Both amp outputs will feed into the relays and the speakers are the output. When you power up the surround receiver it will send the output from that receiver to the speakers. Turn the surround receiver off and the tube amp is again connected. Just don't try to drive the tube amp with no load (speakers) connected, highly unlikely as I am sure that you are the only one who turns it on, and you would have turned the surround receiver off before hand. The solution is about as kid proof as you will get. If you would like a schematic, or are not a hobbyest I could help further given time.
Niles SAS-1 is designed for this situation. It is much like Stickleda's idea, but the work is done for you, you don't even have to know how to make a relay work-- just hook it up and go. Trigger it with a cheap wall wart DC power supply running of a switched outlet on your HT gear.

There's even one on Ebay right now cheap. It's not perfect, since there will be relays in your speaker cables, and extra connections, BUT, I don't think there's another way.

If you wanted to, you could probably mod it to use some audiophile approved relays and then write a review for us...