[b0ng0]

Just had my first attempt at a hi-fi amp (as well as first attempt at any electronic project). Have been following Tangent's guide, using all the recommended parts from Digi-Key.
 
Amp works perfectly in the right earbud (although a very faint hiss - barely audible). However, the left earbud sounds like there is a blizzard going through it (although I can still hear some of the music coming through). I hear this really loud hiss even with the input unplugged. 
 
I'm powering it from a 9V battery. However, after reading Tangent's troubleshooting tips and searching the forum, I'm a little stumped as to what would cause this to just occur in the left earbud. 
 
Pics incoming.

 

[b0ng0]

Ok, another weird thing to add - with the power OFF and the input volume up to max, I can very faintly hear the source.

 

[b0ng0]

Pics are here: https://imgur.com/a/ZfQL5#LKiEM
 
I know my soldering is.... imperfect.... but I used my DMM at each step and all seemed to add up.

 

[kriskalish]

b0ng0,
 
I didn't look at this extremely closely, but I noticed a few things:
 
1) You have a lot of dull grey solder joints
 
This is indicative of a "cold solder job."  Basically the solder didn't uniformly reach the proper temperature before cooling. Also it seems to me like all solder just does this if you reheat it enough times.
 
These dull joints can sometimes fail to make any connection at all or exhibit a measurable amount of resistance.
 
 
2) Components are set up in a symmetric fashion, but solder on the bottom is not symmetric
 
Symmetry is good and makes it easy to spot problems.  I noticed that from your photo of the bottom of the board that the 5th pad from the left on the top row seems to be connected to the 6th pad from the left.  The symmetric connection on the bottom doesn't seem to be there.
 
 
Any time you can hear audio from your source without the amp powered means you have some kind of short-circuit between the source and output. Check the resistance from input to output in the channel that is broken and see what you get.
 
 
Hope that helps,
Kris
 
 
 
 

 

[b0ng0]

Funnily enough, most of those solder joints that look a little dull were ones that I did first time. The really shiney ones are the ones I've reheated a bunch of times (although with a 60W iron as opposed to my now disintegrated 25W).
 
I'll test the resistance when in that left channel when I get back from work. I thought there might be a short somewhere, but as far as I can tell, the only path for the input should be across the capacitor, which should block the signal when there is no input.

 

[b0ng0]

After a little testing I'm getting about 5v from the battery to the right output and 0.22v from the battery to the left input - so I think I've found the problem. I just have no idea where to start looking for where the voltage is missing.
 
Edit: I am getting a voltage between the left output (the noisy one) and the virtual ground, but nothing in the right channel. 

 

[nikongod]

Keep looking for stuff that is soldered together that should not be. 
 
I'd bust out a magnifying glass and go to town on the amp. Take your time on it and be methodical. 

 

[b0ng0]

As you suggested I "went to town" with my stanley knife on the whole board and now the hiss it gone! Thank you so much, can't believe how good my hack job sounds!