[moeburn]

A long time ago, I once had a working CMoy.  Then it broke.  This is the 10th time I have tried to rebuild it (same parts, new PCB).  Either it makes this awful clicking noise 3 times per second, or I get the same volume that the DAP is putting out itself, or I get horrible distortion with the louder volume.  

Anywho, with all this testing, I've been using a crappy pair of headphones and a very crappy old mp3 player to test it out, just in case something goes wrong.  And it's a good thing I didn't test it out on my Atrix phone, because that crappy little MP3 player exploded.  One wrong wire jiggled and an 18v short later, and a large white spark comes out of the screen of the mp3 player, CRACKS THE SCREEN, and the mp3 player displays a handy "Your MP3 Player has exploded.  Goodbye." message before it dies completely.

So, in the event that I get my CMoy working again, I would like to be able to actually use it without fear of exploding my headphones and audio sources.  Is there any extra circuitry I can add to protect them?  Could I at least protect the input source with some diodes, so it doesn't explode again?

 

[bidoux]

Buy a pair of cheap transformers from radioshack and manage the wire so that if you fail hard (everybody does from time to time) no loose wire will go close to your DAP. The transformers themselves are not very good but they will let you see if the Cmoy is working or not.
 
While you are at it, buy a small case and build this as an independant box to test all the amps you will be building in the future

 

[Armaegis]

I would also suggest scrapping all the old parts and building a new one from scratch, just to be on the safe side.