[scud80]

i'd like to have a little box that just has two switchable inputs and two switchable outputs, in some combination of 1/4" and 1/8", so i can quickly do a/b comparisons on headphones/amps/etc.  is this something that should be pretty easy to do?  i've never done any electronics work at all, and never used a soldering iron, so it's a little daunting to consider.  any advice on how to even begin planning this would be much appreciated.

 

[Yoga Flame]

I did something like that once, after being inspired by milosz's Amp A/B comparisons thread.
It's easy to do. Simpler than building a CMoy, but a little bit more work than making a basic audio cable.
 
Here's mine:



 
I used a 4PDT switch to keep the ground channels separate. 3PDT would be enough but I think I couldn't find one. The switch toggles between the two 1/4" input jacks at the back. The quick connect terminals on the switch aren't really needed but they made it slightly easier to assemble and allow me to easily remove the switch without desoldering if I ever need it for something else. Also, the switch I used is far bigger than necessary.
 
The 1/4" output jack is "switchable" in the sense that when you plug something into it, the 1/8" jack is cut off.
 
What I found the hardest was the casework, since I don't have access to a drill press. You can see I got my input holes lined up wrong if you look carefully. Working on the plastic with a file is pretty nasty too. Wear a mask if you do that.
 
I hope that helps with your planning. Good luck!
 

 

[nikongod]

Build the 2 boxes separately. 
 
While its possible to build all sorts of stuff in one box you will make life so much easier on yourself to do it separately. 
 
Quote:

 
What I found the hardest was the casework, since I don't have access to a drill press. You can see I got my input holes lined up wrong if you look carefully. 
 

Casework is always the hardest part. 
 
I have a drillpress and I still get the holes wrong. Not enough to matter, but enough that I know it could be better and it bugs me...

 

[scud80]

thanks for the input!  if i made two boxes, could they be identical (2 jacks and a switch on one side, single jack on the other)?  ie, is there any difference between switching inputs and switching outputs in terms of circuitry?

 

[samsquanch]

Something to consider is throwing a resistor across the signal and ground terminals on the jacks (I usually use 10k ohm on inputs, and 1k ohm on outputs). This way if you switch to an input that has nothing connected, or if you switch away from an output, you won't get an annoying buzz.  Here's a crude drawing of an output switcher with resistors.
 

 

[Pars]

Quote:

I have a drillpress and I still get the holes wrong. Not enough to matter, but enough that I know it could be better and it bugs me...

Word   :rofl:
 
Sure glad my family doesn't depend on me being a machinist, cuz they'd be starving