2 sets of inputs for a power amp - OK?

[RichardH]

I'm building an Avondale dual mono power amp, and a thought struck me just now.
I want it mainly for playing good olf fashioned 2 channel music, but I also use the speakers for front channel duty in an A/V setup. Currently, I am passing the signal through the preamp and then on to the power amp. However, this means getting the volume level right, switching the selector to the right place, etc.

The signal comes from my PC, and I have volume control on that - in fact for the rear channels, I have the signal running straight into some homebrew power amps.

It would be nice to skip passing the signal through the pre, and straight to the power amp. I guess I can just put in another pair of phono sockets on the back of the amp, but is there a downside to this? Should I have some sort of switch to select between sources (although I'm trying to make the whole thing more user-friendly for the rest of the family, so I'd like to avoid that if poss).

 

[prowla]

Are you thinking of simply wiring up the second inputs in parallel with the existing ones?
Wouldn't the one output interfere with the other?
(Outputs are supposed to be low impedance, whereas inputs are high. Thus the dormant "input", really connected to the low impedance output of one box, would upset the component connected to the active one.)
You could possibly look at a remote controlled input selector...

 

[RichardH]

Well, that was my question - would the two inputs interfere? Sounds like they would from what you've said.

The alternative is to have a relay based switchbox, so that when the PC is switched on, the relay switches the input from one to the other, but I'd have preferred to not have a switch in the audio signal for normal 2 channel use. Hmmmm.