[LazyAzN]

Nope still didn't work, although it did clarify the right sound a tad... So the question is... where is the voltage missing?

What I did this time is I soldered the jumpers connecting to the ground on the 4th row and soldered it to the 5th to ground the capacitors.

 

[breakfastchef]

If you followed Tangent's tutorials, diagrams (see below), and assembly instructions you should have a functioning Cmoy. When you deviated from this formula choosing a difficult op amp, changing capacitor values, using a rail splitter etc. you moved into 'unchartered waters', so to speak, and added to the complexity of your first project. You may wish to learn desoldering now, and use the other half of the Radio Shack PCB board to try again. I was lucky and my first three Cmoys all worked, so I know it can be done by a beginner (me included).

 

[LazyAzN]

Quote:

Originally Posted by breakfastchef /img/forum/go_quote.gif If you followed Tangent's tutorials, diagrams (see below), and assembly instructions you should have a functioning Cmoy. When you deviated from this formula choosing a difficult op amp, changing capacitor values, using a rail splitter etc. you moved into 'unchartered waters', so to speak, and added to the complexity of your first project. You may wish to learn desoldering now, and use the other half of the Radio Shack PCB board to try again. I was lucky and my first three Cmoys all worked, so I know it can be done by a beginner (me included).

The only thing I varied from is the C2, opamp, the placement of the out and in wires (jumpered though), and the ceramic resistors. The C2 should have no effect since most people recommended .47uf capacitors of any size. The ceramic resistors supposedly should work fine with the opamp. Supposedly this is a problem with the voltage not going through, but it'll take some time to figure out what without a multimeter (will probably pick one up soon).

Besides, I like learning the hard way

.

Here's an update picture btw (much much clearer by moving the camera away a bit)


I moved the jumpers from row 4 to row 5 to connect with the end of the capacitor. Could it possibly be that my switch is connected wrong?... I put the wire from the battery into 1 leg at the end, and the power wire from the CMoy to the other end, leaving the middle connected to nothing. Is this right for an on-on switch?

 

[breakfastchef]

Quote:

Originally Posted by LazyAzN /img/forum/go_quote.gif Here's an update picture btw... Could it possibly be that my switch is connected wrong?...

I did not see any solder bridges in your photo. Yes, if the switch is wired wrong you would get no output or other unusual results. You need the pin out diagram from the manufacturer to know what needs to go where.

 

[Pars]

Quote:

Originally Posted by LazyAzN /img/forum/go_quote.gif <snip>Could it possibly be that my switch is connected wrong?... I put the wire from the battery into 1 leg at the end, and the power wire from the CMoy to the other end, leaving the middle connected to nothing. Is this right for an on-on switch?

Those are ceramic capacitors, not resistors BTW.

As for your switch, if it has 3 terminals on it, you need to use the middle terminal in conjunction with one of the outer terminals. The switch will be on when the lever is pointing away from the outer terminal you are using. Using the two outer terminals will result in OFF always.

 

[infinitesymphony]

Until you work out how to connect the switch, you might try wiring the battery harness directly to the board. That way, you could rule out the SPDT as the source of the problem.

 

[LazyAzN]

Well today with Footemps help (mostly him working), we discovered that yes, the switch was wrong. It was meant to be in pins 1-2 or 2-3... instead of 1-3 (whoops). Anywho, the left channel now works. Now the issue is the right channel. So being my little solder happy self, I cut off the wires connecting to the pot, connected the line in wires to the line-in stereo jack as well as the line-out wires to the line-out stereo jack. So what I've noticed so far is that APPARENTLY... the right in/out (red wires) is the left channel, while the black is not receiving any sound at all.

Before I went on my pot wire cutting frenzy, I maxed out the pot, and a faint but clear sound was coming out of the right speaker, while the red amplified the sound.

So now I'm pretty dumbfounded as to why the right channel didn't work, even though me and Footemps checked for solder bridges, any steps I may have screwed up, and even reflowing all the solder...

Could this have to do with a burnt capacitor???... I'm not sure... Going to recheck the connections later on in the week. What I also did notice though, was the copper trace for the battery+ volts rose, so I'm not sure if that could play a role in no power for it. How did my sound get inverted in the first place...

 

[Pars]

Quote:

Originally Posted by LazyAzN /img/forum/go_quote.gif Well today with Footemps help (mostly him working), we discovered that yes, the switch was wrong. It was meant to be in pins 1-2 or 2-3... instead of 1-3 (whoops). Anywho, the left channel now works. Now the issue is the right channel. So being my little solder happy self, I cut off the wires connecting to the pot, connected the line in wires to the line-in stereo jack as well as the line-out wires to the line-out stereo jack. So what I've noticed so far is that APPARENTLY... the right in/out (red wires) is the left channel, while the black is not receiving any sound at all.

Tip on the jacks is left channel, ring is right channel, sleeve is ground. You can use either side of the Cmoy board for either channel (your decision), so however you wire it will determine which channel is being done by which half of the opamp. You need to ohm the jacks out to determine which connection is which channel per the above (tip, ring...), or consult the datasheet for the particular jacks you are using.
Quote:

Originally Posted by LazyAzN /img/forum/go_quote.gif Before I went on my pot wire cutting frenzy, I maxed out the pot, and a faint but clear sound was coming out of the right speaker, while the red amplified the sound. So now I'm pretty dumbfounded as to why the right channel didn't work, even though me and Footemps checked for solder bridges, any steps I may have screwed up, and even reflowing all the solder... Could this have to do with a burnt capacitor???... I'm not sure... Going to recheck the connections later on in the week. What I also did notice though, was the copper trace for the battery+ volts rose, so I'm not sure if that could play a role in no power for it. How did my sound get inverted in the first place...

See above... wiring. Burnt capacitor... extremely unlikely. Which cap are you talking about anyhow?

Most of these problems are the result of a missing or bad connection in the feedback loop of that channel (R4 and R5/jumper). As for what you mean by the copper trace for the battery+ volts rose, do you mean that you lifted a pad via soldering/desoldering?

 

[FooTemps]

Quote:

Originally Posted by Pars /img/forum/go_quote.gif Most of these problems are the result of a missing or bad connection in the feedback loop of that channel (R4 and R5/jumper). As for what you mean by the copper trace for the battery+ volts rose, do you mean that you lifted a pad via soldering/desoldering?

Yeah, the pad lifted.

 

[LazyAzN]

Ok, so I took some voltage readings with a multimeter (finally bought one...).

- The op-amp does receive the proper voltage of ~4.5v where the bridges connect from C1 to the ceramic capacitor
- My DC offset right now is ~41 mV, which is probably expected since one channel is dead.

Exactly how do I test the voltages through the resistors? Or what else can I test since I know power is flowing directly to the op-amp?

 

[error401]

Quote:

Originally Posted by LazyAzN /img/forum/go_quote.gif Ok, so I took some voltage readings with a multimeter (finally bought one...). - The op-amp does receive the proper voltage of ~4.5v where the bridges connect from C1 to the ceramic capacitor - My DC offset right now is ~41 mV, which is probably expected since one channel is dead. Exactly how do I test the voltages through the resistors? Or what else can I test since I know power is flowing directly to the op-amp?

Voltage is a relative concept. It's the measure of potential between any two points in a circuit. Usually absolute voltages in a circuit are referenced to a ground point, but it is possible to take many other useful voltage measurements between points in the circuit. If someone asks you 'what is the voltage at point X', they expect that you will measure the voltage with respect to ground, so place the black lead at ground and the red lead at the indicated point. If someone asks you to 'what is the voltage across (or dropped by) component X', you should measure the voltage between the two component leads, instead of referenced to ground.

 

[LazyAzN]

Quote:

Originally Posted by error401 /img/forum/go_quote.gif Voltage is a relative concept. It's the measure of potential between any two points in a circuit. Usually absolute voltages in a circuit are referenced to a ground point, but it is possible to take many other useful voltage measurements between points in the circuit. If someone asks you 'what is the voltage at point X', they expect that you will measure the voltage with respect to ground, so place the black lead at ground and the red lead at the indicated point. If someone asks you to 'what is the voltage across (or dropped by) component X', you should measure the voltage between the two component leads, instead of referenced to ground.

So can you tell me what I should be looking that requires me to measure for the two component leads instead of referencing it to the ground in this case (besides the DC offset if it counts)? I was double checking to be sure that the bridge was at least sending voltage over in case a channel was not receiving enough voltage.

 

[error401]

Quote:

Originally Posted by LazyAzN /img/forum/go_quote.gif So can you tell me what I should be looking that requires me to measure for the two component leads instead of referencing it to the ground in this case (besides the DC offset if it counts)? I was double checking to be sure that the bridge was at least sending voltage over in case a channel was not receiving enough voltage.

You've already checked that the opamp is getting +/-4.5V on the power supply pins (compared to ground), as far as I can tell. That's really the most useful voltage measurement to make in this simple circuit.

I think you will need to just go through the circuit with your multimeter on 'continuity' mode and verify that all the connections that should be connected, are.

 

[LazyAzN]

Quote:

Originally Posted by error401 /img/forum/go_quote.gif You've already checked that the opamp is getting +/-4.5V on the power supply pins (compared to ground), as far as I can tell. That's really the most useful voltage measurement to make in this simple circuit. I think you will need to just go through the circuit with your multimeter on 'continuity' mode and verify that all the connections that should be connected, are.

Can you give me a link or tell me how to do a continuity test (sorry, this is basically the first time for me using a multimeter other than the purpose for testing voltages or resistance on resistors)?

(I think I have a slight idea, set it to ohms and see where it stays at infinity on the multimeter). Is the input capacitors supposed to stay at infinity, because my inputs are at infinity (along with the leg of the C2 capacitors(which is that supposed to happen?)

Edit: Got it... Apparently one of the pins for the socket was not fully soldered. But now the left channel is massively louder than the other and is having massive clipping (as in, lowest setting for VC + highest WAV in volume control in windows + 3% volume in winamp gives the most bearable level to listen, while the right I don't hear until I crank the VC to full) . Before I was getting 4.53v on + and -, but now I'm getting 5.12v on + and 3.8v on -, so I'm wondering how it suddenly became imbalanced...

the difference in DC (or if its DC offset, not sure) is 48 mV idle. That increases to around 50-60 mV when under load... Should I go buy another rail splitter and hope it fixes this problem?

 

[error401]

Quote:

Originally Posted by LazyAzN /img/forum/go_quote.gif Can you give me a link or tell me how to do a continuity test (sorry, this is basically the first time for me using a multimeter other than the purpose for testing voltages or resistance on resistors)? (I think I have a slight idea, set it to ohms and see where it stays at infinity on the multimeter). Is the input capacitors supposed to stay at infinity, because my inputs are at infinity (along with the leg of the C2 capacitors(which is that supposed to happen?) Edit: Got it... Apparently one of the pins for the socket was not fully soldered. But now the left channel is massively louder than the other and is having massive clipping (as in, lowest setting for VC + highest WAV in volume control in windows + 3% volume in winamp gives the most bearable level to listen, while the right I don't hear until I crank the VC to full) . Before I was getting 4.53v on + and -, but now I'm getting 5.12v on + and 3.8v on -, so I'm wondering how it suddenly became imbalanced... the difference in DC (or if its DC offset, not sure) is 48 mV idle. That increases to around 50-60 mV when under load... Should I go buy another rail splitter and hope it fixes this problem?

You should watch tangent's tutorial on using a multimeter: How to Use a Multimeter

Some meters have a dedicated continuity function that will beep when there is continuity, basically just that two spots are directly connected. If your meter doesn't have such a feature, set it to the lowest ohms range, you're looking for low numbers, say < 20 ohms. You can use this function to test that points that are supposed to be connected are, in fact, connected. You can also test that points that aren't supposed to be connected aren't.

Capacitors block DC current (which your meter uses to measure in the ohms range), so they will measure as an open circuit (very high resistance). In fact, that's exactly what they're used for in this circuit, to prevent any DC the source is sending from being amplified.

It's strange that neither channel is working, but in completely opposite ways. I would investigate R3 and R4 (the gain setting resistors) and make sure you've put the correct values in the correct spots. It sounds like the gains on both amps are wrong. I think the power supply is probably okay, you can check by removing the opamp from the circuit and checking the voltages again. Probably the clipping is drawing too much current for the TLE to stay in spec. Check for continuity between ground, +ve and -ve rails though just to be sure. None of the (3) readings should be lower than 10K ohms.