[aid3nn]

Hey, its my first time trying to build a cMoy amp. I have the 220MF caps in the right direction and the 4.7k resistors in the right spots as well. When i hook up the 9v battery and test the output voltage it gives me +/- 2.15 volts on either side. Anyone have a clue as to what might be happening? Thanks

Dave



http://www.tehflo.com/cmoy/cmoy1.jpg

http://www.tehflo.com/cmoy/cmoy2.jpg

http://www.tehflo.com/cmoy/cmoy3.jpg

 

[gsteinb88]

Where are you testing the output voltage?
-g

 

[aid3nn]

from the jumper on the virtual ground, to where the power output will be to the dual op-amp

 

[gsteinb88]

Then likely that is what you should be getting. If you want to see 9v go check from 9+ to the 9-. Nothing is wrong, AFAIK. Enjoy building your amp!
-g

 

[aid3nn]

oh, alright, in all the guides, it states i should get about +/- 4.5 volts output because it splits the voltage. But if around 2.15 volts is correct for a single 9v then i guess ill keep building the amp. someone let me know if its supposed to be different. thanks

 

[Pars]

What does the battery itself measure? If its not about 4.3V then you do have something wrong. If that is the case, doublecheck all your jumpers and solder joints to make sure there isn't a short or a bridge.

 

[aid3nn]

there are no shorts, the orientation of the pieces are correct, ive tested the batt. its 9.3v (new), ive tried replacing the caps, changed to 1% tolerance resistors. Ive posted pictures, i thought maybe someone here in the forums could see something i couldnt. if someone can spot the problem that would be great, because im going nuts trying to figure this out.

 

[gsteinb88]

Okaay, my mental math fails. I would check out those soldering joints on the bottom, they dont look very solid in the low quality picture. That could be adding extra resistance to the circuit.
-g

 

[aid3nn]

just cleaned up the circut of some sloppy joints. nothing happened. anything else to try? or is my cMoy doomed only at the power stage?

 

[aid3nn]

got the amp working, guess i just got messed up with the whole "virtual ground" thing. Thanks for all you guys' input, ill be sure to frequent these forms alot more.

 

[robzy]

Are you measring +/-4.5v? If not then you really should look into why...

Rob.