[tehspork]

I recently put together my first cmoy, and to my dismay I get no sound out of it, and turning the volume to max produces a popping, crackling noise. Any ideas as to where to look to fix this problem?

 

[mminutel]

Most all of my problems with my first CMOY were caused by solder bridges. Go through your joints with a magnifying glass and make sure that there aren't any bridges. Also, wiggle the wires and see if any of them have bad solder joints.

Have you made sure you have half of the voltage on the wires leading under the board?

 

[bhjazz]

Check for flux bridges, as stated above.

Next, reheat as many joints as you can. It sounds like you have a ground problem, and that can occur just about anywhere.

 

[xmokshax]

Quote:

Originally Posted by bhjazz /img/forum/go_quote.gif Check for flux bridges, as stated above. Next, reheat as many joints as you can. It sounds like you have a ground problem, and that can occur just about anywhere.

out of curiosity, how much impact can flux bridges have on an amp's performance? does some flux actually conduct to the point where a flux bridge can render the amp non-functional?

 

[tehspork]

I've checked for voltage, both sides seem to be right (4.6 and -4.6 from a single 9v). Upon further listening, turning the sound all the way up you can just barely hear the music, but there is a ton of crackling and noise over it. Would the lack of sound be a sign that I damaged the opamp chip somehow?

 

[Logistics]

Did you by any chance leave out the input caps? (films in the guide)

 

[Joshatdot]

did you forget the R5 jumpers?

 

[AudioCats]

sounds like a self oscilation problem, if the chip gets really hot then it is......

 

[tangent]

Quote:

Originally Posted by xmokshax /img/forum/go_quote.gif how much impact can flux bridges have on an amp's performance?

I'm sure I'm not alone in having an experience with an amp that didn't work at all until I defluxed it.

Quote:

does some flux actually conduct to the point where a flux bridge can render the amp non-functional?

Yes, some types of flux are inherently conductive. But, that's not the full extent of the problem. Carbon is also conductive, and heating organic materials to several hundred degrees tends to produce carbon. I suspect that this is one of the ways that "non-conductive" fluxes can become conductive in practice.

 

[vixr]

Quote:

Originally Posted by tangent /img/forum/go_quote.gif ...Carbon is also conductive, and heating organic materials to several hundred degrees tends to produce carbon. I suspect that this is one of the ways that "non-conductive" fluxes can become conductive in practice...

It sure pays to read these threads...

 

[tehspork]

I fixed it, turns out it was a ground issue - cold joint on the jumper between input cap and ground. Thanks to everyone for the suggestions