Connecing Balanced and Unbalanced at the same time

I will ask the question first then will tell you what I am thinking about doing. Can I connect balanced and unbalanced cables to my 9BSST at the same time? And everytime I want to use the source that's connected to either one of them, I will change the switch on my amp's channels. I have a 9BSST and currently using a receiver (Pioneer Elite VSX-55Tix) acting as a preamp/processor, and it is currently connected to the amp using unbalanced connectors. My objective is to improve the sound in stereo mode. I am thinking about buying a DAC with a volume control and connect it to the amp using balanced connectors when I listen to music. When I want to watch TV or movies, I will turn my DAC off and switch the connectors on the amp to unbalanced so it will gets its feed from the receiver. I know that this will be inconvenient, however I won't have to spend large sums of money on a good preamp/processor. If you have a better way of doing these, please let me know.

Your feedback is greatly appreciated.

Yes you can do that if you don't mind switching.

And, to avoid having to switch when you don't feel like it, get a Wadia or Levinson DAC (and there might be a couple others). They both have volume control, AND they both have RCA and XLR outputs THAT CAN BE USED SIMULTANEOUSLY. So you hook the DAC's RCA outputs up to your processor and when you don't want to (can't?) get out of your chair, you just listen to CDs through the processor. Also makes it fun to A-B a CD with its vinyl brother.
I think you need to contact Bryston before doing this. Does the manual say not to connect both? Most equipment with balanced and unbalanced inputs have the unbalanced input tapped off one side of the balanced input. When unbalanced is selected, the second signal of the balanced input is shorted to ground.

If this is the case with Bryston, and you have equipment connected to both, it may produce a very low input impedance on the tapped line. This occurs because active source component will be driving the output impedance of the other source component connected. In addition, the balanced source will be driving a short to ground if it is turned on when unbalanced input is selected on the amp. This could fry the output stage.
Thank you for your response, however you triggered some questions! If I connect the DAC using balanced to the amp and unbalanced to the processor, Would I be able to use this setup when watching DVDs? My objective is to bypass the DAC when watching movies. If I can use the DAC while watching movies, ie have the front channels go through the DAC to the amp, then it will be a better setup. However I don't think that I can do it.

So lets see if I understand. You have a multiformat player with both a coax and perhaps a Toslink 2-channel digital out you can feed to an outboard DAC, correct? (For movies, I presume the player is connected to the processor with analog outputs so the processor can make 5.1 surround out of it -- since most players don't output 5.1 digital data and most processors don't accept it anyway.)

Sure you can bypass the DAC when watching movies. The DACs RCAs are just another source to the receiver/processor. I don't know exactly how your Pioneer is configured but it seems to me that what comes out of the L and R "to main speaker stereo amp" outputs depends on kind of source for whaich you configure (select) the processor?

BTW, when you flip the sitch on the Bryston, does it change the configuration of all the amps or is there a switch for each of the amp sections?
Jimangie, I am planning on contacting Bryston because what you mentioned is what I am afraid of.

Nsgarch, I was thinking about connecting my cd player to the DAC using Toslink and connect the DAC directly to the balanced connectors on two of my 5 channel amp. I will switch the selector on each channel to balanced. This should work. Now I would connect the front R+L Pre-out on my receiver to the same channels using the unbalanced connectors. So when I am watching movies, I switch to unbalanced and the DAC is not used, and when I listen to music I would turn off the receiver and my DAC will be passing the signal coming from my transport.

I am just trying to save buying a preamp/processor if I can.

kas, isn't the Pioneer a preamp/processor?
Well, it is a receiver so yes it is an amp/preamp/processor in one box. However I am trying to avoid buying a Bryston SP2, or a Krell.

I would look for a decent 2 channel preamp with a HT pass through instead. You will most likely end up with better sound (I don't like systems with no preamps) as it buffers the amp connection with both HT and music. Plus, you have a much simpler system to use, and a much great, and cheaper, selection of cd players.
I don't know about your amp specifically, but on most that have both single-ended and balanced inputs, the "switch" between them is not actually an input selector in the preamp sense, but is only there to prevent hum which could otherwise be induced (in place of input shorting plugs). If the switch doesn't defeat your presently-used single-ended inputs when flipped over to balanced, this is why, and both sets of inputs are always 'live'. Assuming that's the case, then you wouldn't want to connect two sources to both sets of amp inputs simultaneously because of the parallel impedance.
Zaikesman, I agree with your analysis, and I think that I should drop the idea.

Thanks for all of you, and I appreciate your input.

Try it. No one will punish you. You might even like it.