Two input jacks, one output

[Firequacker]

I didn't know what kind of keywords I could have used to search this one, so I just decided to post it... Sorry if it's been discussed before.

Anyways, my friend and I were talking and some way or another the subject of music and guitars came up, and I was talking about his practice amp and I remembered the one time we both tried to use it, but it only had one input. Back to the current conversation, I told him about the Tube Screamer I had just completed, and that I had enough general knowledge to come up with some schematics and build something to create two input jacks on his amp, all contained in an enclosure that was small and portable, and he asked if I could make him one.

SOOO, I just have couple questions about this sort of thing.
1. Is it really as simple as I would imagine it to be?
2. What are some good ideas for enclosures that I could find around the house?
3. What kinds of potentiometers should I use for the individual volume controls for each input?
4. Is it possible to construct this without the use of a power source, as in utilizing only the electrical signal from the pickups of the guitars themselves?


And another question I forgot to ask in my thread about potentiometers, which of the lugs is meant to have what soldered to it? I also read in another thread around this forum that it is a good idea to coat the inside of non-conductive enclosures with tin foil, is this true? If so, why? Sorry for all the questions, I'm just trying to learn as much as I possibly can about this stuff so that I don't end up wasting all my money.

Thanks in advance,
GC

[Pushtone]

Any passive mixer design or simple ABY switch will work.

But before you start building...
I'm thinking of a little DOD passive instrument mixer.
Ask your local dealer if they have any DOD, Rolls, Yorkville boxes that will do this. I bet you could find a cheap product.
Like the mixer on this page ... http://www.dod.com/accessories/accessories.htm

You can also use a passive ABY box backwards as a low tech solution. That would be the easiest.


If I were to do this, I would modify the front panel of the amp and add the extra jack there, or on the side.
That would be cheap, no box to buy and just one jack.
A schem of any Fender amp will show how to wire Hi and Low jacks with minimal loading., or just Y it.

If you want to go external just a small box, like a 1590A, and three jacks should do it. About $25.00 I figure.
There may be some strange results when each of you use your guitar volume knobs because of loading.
You'll have to use your picking dynamics to mix your sound instead.
If each guitar where plugged into a BOSS pedal of its own BEFORE this box the bypass buffer would help the loading.
Look at any Fender amp schem to wire the jacks as Hi and Low or just "Y" it.