[mateo05]

I'm working on my semi-first CMoy (I tried one a while back w/ 2 single-channel opamps that I sucked so badly at and gave up halfway through), and I'm getting a lot of static and distortion with it. I've checked for solder bridges and shortcircuits, but see none, which brings it down to two things. I accidentally touched a power cap w/ my solder iron for maybe 2-3 seconds, and the outer coating is a bit damaged in that spot- would this damage the cap itself? Also, I'm very unsure on the grounding scheme, which is the one thing I'm still a newb at in this area. I don't have a ground plate per se, so I'm relying on just connecting the grounds together w/ hookup wire. Do all the signal grounds connect together, or do they just connect for the one channel? Are the signal grounds connected with the "virtual ground" of the power supply? Does the use of a tin or actual ground plate rather than just connecting by wire affect the sound or connection any?

I'm going to continue work on troubleshooting this, but it'll help to have some guidance along the way. Thanks for all help

.

 

[meat01]

It really sounds like a grounding issue. All of the grounds should be connected to the same place. Are you using Tangent's Guide ?

 

[mateo05]

I really thought grounding, too, but the cap threw a wrench into it all. I'm sort of using Tangent's guide; I used the micro-CMoy layout as inspiration, though mine is slightly different. I know how to read the schematic, and so I just soldered things according to that along the way. I don't, or rather haven't been doing, jumpers, as it just isn't my style- I just lined everything up so I could bend the legs together and solder that joint, and then use a bit of wire in one or two spots. Do you mean the power supply ground should be connected to the signal grounds as well? And like I asked before, does me just using a wire to connect all the grounds make a difference?

 

[Achtunghoy]

Do you guys solder all the ground wires to the bottom or top?

 

[mateo05]

I have my signal ground on top, but the power supply ground on the bottom. Turned out this way because I did the resistors vertically to the board, and R2 and R3 were sticking up next to each other. I think I'm just going to go back and rebuild, I just found out that one of the leads from the battery to the circuit wasn't too secure, and who knows what else I might uncover.

 

[meat01]

On the Cmoy's I have made, there is only one ground and all of the grounds connect to it, whether it is signal or power ground.

 

[mateo05]

OK, I didn't do that...but just wiring all those together rather than soldering to a ground plate doesn't make a difference, right?

Also, do the film caps in the signal path have any polarity?

And I forgot- do the in and out jacks' grounds go to the same common ground too?

 

[tangent]

Quote:

just wiring all those together rather than soldering to a ground plate doesn't make a difference, right?

Yes, it does matter. If you solder all the ground wires to the ground bus on the protoboard, you have one ground. If you solder all the ground wires together, you have a second ground: the one the resistors (R2, R3...) connect to.

Quote:

do the in and out jacks' grounds go to the same common ground too?

Yes.

 

[mateo05]

Ok, newb time...I'm using a cut down Radio Shack breadboard, one of the ones with all the little copper squares on it. I don't think there's any sort of ground bus there, is there? And just to be absolutely clear here, the power supply virtual ground goes to the same ground as the signal? If so, what makes it "virtual"?