Mono Blend Box?

[clister01]

I'm pretty much a paint by numbers guy over here but a buddy of mine but I wanted to see if anyone had any info on this.  What he's looking to do:

Feeding the output of two separate mic preamp signals into one box that will sum the two signals into one mono output.  But he needs a pot to blend (so he can dial in more of preamp #1 or #2 to taste) between the two.

Mic Pre Output #1 ----> Input #1 to SummingBox \
                                                                      ---------> Blend pot between the two signals -------> Mono Output
Mic Pre Output #2 ----> Input #2 to SummingBox /

Does that make sense?  I understand that if it was just summing the two signals together could be done passively with a resistance network, but I have no idea really how to implement the blend pot.  Anyone have any tips? pointers? schematics? Anyone built something like this before?

Thanks for the help,

Cameron

cameron (dot) lister (at) gmail (dot) com

 

[clister01]

Just thinking about this now after posting.  It would be cool if there was a way to get the pot to be center = equal amounts of signal from input 1&2 summed together and then panning left or right increased amounts of one input and decreased amount of another and vice versa.

 

[clister01]

Doh! Looks like I'm just building one side of the Crush'n'Blend circuit.  Anyone made one like this yet?  Just a mono summing unit w/blend?  Any tips on schematic changes if necessary? Made a PCB?

 

[PRR]

In unbalanced hi-Z world, this is trivial:

If both inputs are identical, the output load should be infinite. (But if both inputs are identical, nothing happens.)

If the two inputs are totally different (DJ cross-fader from one song to another), I think the constant-power solution is 11K or 12K load (assuming 10K pot). Constant power is not constant loudness (twice as many instruments sounds like more even if power is constant). And your proposed use is not two utterly unrelated sources. And my sticky slide-rule may be giving me a bad answer. So look under your bench for any orange-stripe (10K-99K) resistor, drop it in, see how you like it.