Altoids Tin 1/8" Stereo Mixer

Step 11: Attach First Resistor to Outer Tab (Left Channel)

1) Take a resistor and attach to the outer/left-challe tabs of the output jack (the one by itself) and the closest input jack (see picture).

    - Make sure the resistor body is closest to the first input jack.
    - solder in place

NOTE: it is very important that there are no shorts with the ground wire, case or other tabs from this point on.

Comments

[richfiddler11]

Honestly, I've built quite a few of these and never had any problems with shorts -- the resistor leads are rigid enough not to flex much on their own, even with a pretty decent shock. Even if there was a short, it would not cause any permanent damage.

But ...  if you're the sort of person who stays awake at night worrying about this sort of thing, you could also try these alternatives:

1) "spray on electrical tape" http://www.plastidip.com/home_solutions/Liquid_Tape

2) Potting: The ultimate in shock-proofing.

'Potting' in electronics means to fill in the air space in the circuit enclosure with a suitable compound (non-conducting, non-corrosive, etc). Electronics-grade epoxy is used as a potting compound in military, automotive, aircraft, etc. This stuff is expensive and bullet-proof (figuratively speaking ;^)

Electronics-grade silicone RTV is a cheaper alternative: http://www.amazon.com/Clear-Electronic-Grade-Silicone-Cartridge/dp/B0063U2RPW/ref=sr_1_3?ie=UTF8&qid=1349801014&sr=8-3&keywords=electronic+grade+silicone

And cheaper yet would be to fill the box with melted candle wax (parafin).

With any of these, make sure your circuit works perfectly before applying the insulator and wrap your connectors with tape to keep insulator out of the contact area.

Or, just build it, see that it works fine without insulation and forget about it.

Rich

[matricha]

I have found that lengths of plastic insulation from stripped wire slipped onto the leads does a fine job of insulating.

It takes a while but is easier than wrestling tape.

[autonomousoperations]

Random though: use electrical tape at points that are likely to short so if it ever gets dropped or thrown around it does not short.

[torndorff]

 Cover the inside with a couple layers of electrical tape.  Not only does it protect from shorting, it also makes the whole box sound a little more solid.