2x1 sum

[johnnyscotch]

Sorry if this has been done to death, I searched the META, and found this:
http://www.groupdiy.com/index.php?topic=8199

But, I have a further question and the "dialog box" suggested I start a new thread.........

I want to build a simple little box to take 2 outputs from my external preamp and sum them to one output. They'll be balanced 1/4" connectors that I'll put in my patchbay.

I basically want to sum together (for example: Kick in/out OR Snare up/down) together on one track (respectively).
I'd like to make a couple of these "fancy y-cables".

Here's my question: I have a grasp on NYDave's math, it seems pretty simple, but what if I want the option of going out to one of many different inputs, like maybe I go to straight to A/D converters OR to my tape machine, OR to an EQ then to one of those destinations???
Since these devices likely have their own input impedances, is there some "middle-ground" impedance, or average, or "rule of thumb" impedance I can use that will likely satisfy most line level inputs??

Would I be better off using one of Jeff's API ACA summing PCB thingys??

I don't care if it's active or passive.

Thanks!!!

Eric

 

[lassoharp]

You could use a transformer for 2 to 1 mixing.  Most any 1:1 with CT should do it.  Simple construction. Do expect some varied coloration.


http://www.edcorusa.com/products/143-wsm600-600.aspx

 

[Sarcastic Sound]

I've wired passive summing points on patchbays, 2 to 1, with 2k resistors on pins 2 and 3. It works just fine for $2 worth of parts and a little bit of time. There is some gain loss but easily made up.

Sonically it works... no magic.