Dual 1/4" input switch box question

[acobberson]

So I'm still fairly new to electronics and what not. I'm trying to build a dual input switch box for a friend. He needs to be able to use both inputs at the same time (either running keys/guitar through his effects or two guitars). Obviously simply tying the inputs together will cause both guitar volume pots to be in use at the same time, so he also needs to be able to turn one guitar down and still get signal from the other. So essentially he needs to be able to send both signals through at the same time when he is using a guitar and keys but be able to "cancel" a second guitar's volume if he has two guitars hooked up.
I found this thread and was wondering if this would work minus the gain control http://www.diystompboxes.com/smfforum/index.php?topic=89877.0
I'll also be adding a simple buffer circuit. Is there an easier way to do this? Any help at all would be greatly appreciated!

[Paul Marossy]

So I'm still fairly new to electronics and what not. I'm trying to build a dual input switch box for a friend. He needs to be able to use both inputs at the same time (either running keys/guitar through his effects or two guitars).

I don't have any suggestions, just an observation.

The first problem you're going to have is with matching input levels - line level from a keyboard is different than a signal straight from a guitar, which varies all over the place depending on the output of your pickups, etc.

If it were for use with only guitar, then it gets easier.

[acobberson]

Agreed. I have already raised his awareness to that. He'll be running the keys through effects all the time, so unless I add gain control over both inputs he'll just have to compensate his keyboard levels from the keyboard itself. Thanks for the input, Paul!

[GibsonGM]

Try "AMZ Simple Mixer" on this page:  http://www.muzique.com/schem/projects.htm
His stuff works AWESOME.

Omit 2 of the inputs, add a pot and you can match volumes....you can make one of the inputs a switching-type jack, so with nothing plugged in the jack will ground itself (reducing hiss/noise from an open but unused input).   Good stuff 

[Paul Marossy]

Try "AMZ Simple Mixer" on this page:  http://www.muzique.com/schem/projects.htm
His stuff works AWESOME.

Omit 2 of the inputs, add a pot and you can match volumes....you can make one of the inputs a switching-type jack, so with nothing plugged in the jack will ground itself (reducing hiss/noise from an open but unused input).   Good stuff 

Sounds good to me. I couldn't think of a circuit off the top of my head that would fit the bill, but that AMZ project looks like it would work. Just modify it for only two inputs.

[acobberson]

Try "AMZ Simple Mixer" on this page:  http://www.muzique.com/schem/projects.htm
His stuff works AWESOME.

Omit 2 of the inputs, add a pot and you can match volumes....you can make one of the inputs a switching-type jack, so with nothing plugged in the jack will ground itself (reducing hiss/noise from an open but unused input).   Good stuff 

I think that is exactly what I'm after. I kept looking at his jfet splitter but totally looked right over this circuit. Thanks a ton, gentlemen!