Two line sources into one amp

I have a Benchmark DAC 1 which sounds much better driving my power amp directly and bypassing my preamp. Problem is I use the Audible Illusions M3A preamp for my phono set up. Rather than having to switch the DAC1 an M3A interconnect cables to the power amp, can I run both to a RCA combiner jack at the power amp without suffering ill effects (only one source putting out a signal at a time)?

I don't want to fry anything, or possibly compromise the sonics of one source with another.

Thanks for your help.
Not a good idea as one source will shunt the other, even if only one is active at a time.

No. Keep swapping the interconnects, don't try what you're proposing, it won't work well even if the unused component is off or unplugged from the wall. There was another thread about this general question not too long ago that went into some more detail on what Kal says, which you might find in the archives (although I don't know what you'd search under), but anyway that's the deal.
You need an A/B switch or a passive line stage.
A/B swith is what I use to go between HT and tube pre with no passthrough.....good results here.
Continual swapping of your iterconnects will eventually lead to excessive wear and ultimatly the need for replacement (not cheap anymore). I too, recommend a well built "passive" line stage (unity gain, unbuffered and very high quality volume control). I utilize a McCormack TLC-1 Line stage (my 3rd one over the years). It has proven itself to be very transparent, without adding many of the influances of other (active) pre amps. There are others though, that can be had cheaper (than the TLC), and with less selection options. In fact, I spotted (what appeared to be) a well built little passive unit (home made) on the auction, not too many days ago. Passive Pre's (like this one) generally sell fairly cheap, and may suit your needs.

You could very easily pick up an excellent phono amp AND also a hi-end, passive pre amp for the returns on the sale of your Modulus 3A.

Some amps just simply " beg" for a passive pre amp (or, a the very least, direct input). These amplifiers may have inherant tonal qualities (that are so seductive) that any, and all, pe-amp influances will take away from their truth and their individual musical nature.


Thanks for the feedback...

What is a good source for a quality A/B switch, or high quality parts and a project box to build one myself?

Maybe start here?
Try and also parts-express. That sould get you started. There is also Parts Connection and of course, "Rat"-Shack (if you are desperate).

And also: .......... How could any one of us forget to mention the CREEK OBH (passive remote pre-amp) series. I beleive that Moon Audio still has them and Audio Advisor sold them (at one time). They are quick to sell on Audiogon. Perhaps what would help you the most.

I scanned through the Audiogon website looking for something for you. There was (very recently) someone that was selling high quality switches and pots (under tweaks or ss pre-amps) but I could not locate anything now. I did happen to spot a "Quasar" switch box that looked real interesting but it is FAR more than you would need. What caught my eye about it was the (apparent) high quality of exposed parts. Fairly cheap at about 200.00. I don't know a thing about it's insides (could be pure junk). It had a ba-zillion in's and out's and for both amps and source. Made me dizzy looking at it.

Thanks again everyone.

Checkeed out my parts express catalog. Nothing seemed to fit the bill, but I did find this switch on the WEB:

Any thoughts?
The RAM switch will work. Niles Audio makes a signal sensing aoutomatic switch as well as as a manual model.
I ended up with a picture of a vidio switchbox of questionable construction for hi-end audio. If that is what you are looking at, I would pry a bit deeper into its parts quality for acurate audio transfer (ie: type of hookup wire, wiper type and build, and contactor material...silver prefered).