[lehtinel]

Well, this is utterly strange. Built a new Cmoy with a larger 2200uf (yeah, overkill, I know) power caps and a TLE2426 but this thing now gives the same voltages all over. If I plug in a fresh battery, I get some 8.7v between the rails and V+ and V- at the IC-socket.
 
Whats up with that?

 

[Pars]

V+ and V- are the rails, and on a cmoy (or any virtual ground amp), are effectively the + and - terminals of the battery. If you are saying you are getting 8.7V between virtual ground and V+ or V- (on a single 9V battery), then your tle2426 is either toast or not connected correctly.

 

[lehtinel]

Allright, now I cleaned all the flux off usin electronic cleaning spray and a toothbrush. Now it gives even split voltages and good sound, but, the battery drains fast for some reason...

 

[nikongod]

What idle current were you expecting? You can find this info in the datasheets for the op-amp you used, the TL2426, and maybe add 1mA for the monster cap. You can also estimate battery life based on this to see if that makes any sense.
 
If you cleaned the board and it got better, look for unintentional solder bridges. You may have "accidentally" broken a really bad one, but left a less bad one. Troubleshooting sucks, good luck
 
Measure the idle current (there are a few methods in this thread: http://www.head-fi.org/forum/thread/531454/mullet-a47-thread/15#post_7179598) and if that dosnt make sense report back.
 
As another thing to check: is the op-amp you used known for poor stability at low gain (if you built with low gain) or with low power supply voltages? If either of those things applies, can you get a different op-amp? Can you get a different op-amp just on principle?