Cmoy build (first time) uneven voltages

Allright, bare with me here. An engineering student for two years back in 2001-2003, never did anything practical over there, Im ashamed to say I've forgotten most of the theory we got or atleast it's buried somewhere in the back of my brain.

But anyway, lets cut to the chase. I built the Cmoy amp according to Tangentsofts excellent instructions, using the recommended capaciotor and resistor values, OPA2132P etc., the only big difference is the protobord I used. It has three connected rows, so I had to modify the layout to work.

Allright, all set up, theres sound, no distortion, no noticeable weaknesses in sound either, but, I can measure a huge difference in voltage at the caps, +2.7V / -6.6V and sone 1.4 - 2V at the IC V- and V+ pins. Also, if I disconnect the battery - the signal still plays trough, should it be doing this? 

A picture (no closeup though, my macro lens is some 500km away) from this morning.

Cheers, plugged out my OPAMP and measured voltages again, now it gives me +9v an -0v so everythings on the plus side. I noticed I have soldered the IC socket with the notch upwards, but still I had my chip installed with the notch pointing down so by all logic I should be fine there. 

Quote:

Originally Posted by Soymilk 

the socket orientation has nothing to do with anything, it is simply a socket, nothing more, nothing less.

 

if your cmoy isn't powered but it's still playing, that would lead me to believe your output is directly connected to your input. recheck your layout.

Jup, I kinda guessed the socket doesn't do more than lead the signal through. Will have to check the input / output coupling thing.

Thanks
 

Allright dudes, friday evening fine-tuning, no stress. I got the voltage settled at 4.5 for both sides, nice, it was probably a bad soldering problem that bridged in the power section. 

The sound is improved a lot, but, theres a constant hiss or buzzing sound. And the amp music still plays trough if I remove my battery. I can't find any bridge between input / output that would cause this.

Okay, got the buzz fixed and now it doesn't even play trough when I take the battery out - but, the sound is very muddy...hmm

Allright, found my extension tube so: 

And yes, it's intresting indeed and very nice to learn.

Mmm...in the Tangentsoft guide the 100nF caps are in line with R2 and the OPAMP first and second (input) rows. a detail of my underside: 

Allright, well, I've been tinkering around and I can't get the sound decent enough. What I've got at home partvise is 470nF 250V capacitors and I could switch R3 and R4 to 4.7kΩ for a gain of 3. Now the cans Im currently on are Koss Porta Pros at 60ohm but my main cans are Sennheiser HD600 so will the low gain cause problems there?