OK thank you,
For when you see this tomorrow I have fixed the break in the trace and now have a nice positive voltage on pin 8 ,which is the same as the voltage on R8.
Pin 7 now have a voltage of plus 8.09V. Which seems better!
Thanks a million, really really grateful for the help so far.
Michael
For when you see this tomorrow I have fixed the break in the trace and now have a nice positive voltage on pin 8 ,which is the same as the voltage on R8.
Pin 7 now have a voltage of plus 8.09V. Which seems better!
Thanks a million, really really grateful for the help so far.
Michael
So that's a definite fault fixed. Have you refitted the FET and tested it all again ?Man I am my wits enf with this amp. Turned it all on and check the negative rails. All seemed good at -11.86.
But alas no sound came out when I plugged it into the computer.
Just got some static when twiddling the volume knob.
I think this could be down to a couple of problems. Either I killed the FET when removing and reinstalling or a broken trace.
I quick short between the negative rails on U1-4 confirmed the Amp + DAC was still working without static.
Let me have a quick tinker and see what I find.
Michael
But alas no sound came out when I plugged it into the computer.
Just got some static when twiddling the volume knob.
I think this could be down to a couple of problems. Either I killed the FET when removing and reinstalling or a broken trace.
I quick short between the negative rails on U1-4 confirmed the Amp + DAC was still working without static.
Let me have a quick tinker and see what I find.
Michael
Well its now working...
I turned it on with the negatives shorted together on all but U2 and then removed the shorts one a time to see which would make the amp go crazy.
None did.
Its now working with the only fault being it is extremely quiet.
With the gain button in and the volume right up its not even loud, I have to still strain my ears to hear it.
But this could be a windows fault. I will look into it.
Michael
I turned it on with the negatives shorted together on all but U2 and then removed the shorts one a time to see which would make the amp go crazy.
None did.
Its now working with the only fault being it is extremely quiet.
With the gain button in and the volume right up its not even loud, I have to still strain my ears to hear it.
But this could be a windows fault. I will look into it.
Michael
Fault finding always has to be logical.
Up until now we've been concentrating solely on a power supply problem. If all the opamps now have the correct supply voltages present then we can move on.
You need to confirm that first.
If the amp consistently works OK with a DAC or CD player but is much to quiet on your PC then it really does sound like a Windows setting somewhere. The O2 is configured to work with any normal line level output.
Up until now we've been concentrating solely on a power supply problem. If all the opamps now have the correct supply voltages present then we can move on.
You need to confirm that first.
If the amp consistently works OK with a DAC or CD player but is much to quiet on your PC then it really does sound like a Windows setting somewhere. The O2 is configured to work with any normal line level output.
Its a fresh new day and a different perspective on this amp.
I forgot last night an easy test to see if it was an amp or windows issue was to try the 3.5mm jack input and see if it worked well.
Low and behold its rock solid.
So either a DAC problem (highly unlikely) or windows problem (very likely!).
I really cant thank you enough Mooly, for all the help. I had no clue where to start and you turned this project around for me.
Many many thanks,
Michael
I forgot last night an easy test to see if it was an amp or windows issue was to try the 3.5mm jack input and see if it worked well.
Low and behold its rock solid.
So either a DAC problem (highly unlikely) or windows problem (very likely!).
I really cant thank you enough Mooly, for all the help. I had no clue where to start and you turned this project around for me.
Many many thanks,
Michael
Right 100% working now.
Notes for the future are: plug it into a rear panel USB port not a front USB and make sure windows isnt trying to do some funky audio effects.
Once again Mooly thanks so much. Not every day do you come across someone with the patience to work the problem.
Thank you once more,
Michael.
Notes for the future are: plug it into a rear panel USB port not a front USB and make sure windows isnt trying to do some funky audio effects.
Once again Mooly thanks so much. Not every day do you come across someone with the patience to work the problem.
Thank you once more,
Michael.
So I finished building my Objective 2 yesterday. At first there was no sound at all, so although the joints looked fine, I went ahead and reheated all of them and then THERE WAS SOUND! 
Really awesome sound but only for about ten seconds... then one of the ICs (Q1 - 2068DD) started to smoke a bit and then a really scary (And very very loud) rhythmic popping came from my sacrificial Jays.
When I tried again about half an hour later even though Q1 had smoked pretty bad, there was sound, again, although I turned it off quickly when I felt Q1 heating up again. All the other ICs are cool to the touch. I thought I might have messed up with the resistors, causing it to be fed too much power for some reason, but then what I do hear before it overheats is balanced (I'm assuming that one channel would be louder if that was the problem?) I triple checked the whole circuit and it's as it should be...
Wai is Q1 being grilled while everything else is fine?
Since my knowledge of electronics is rather limited so I was hoping that maybe one of you pros might be able to help me here... Xoxo...
Really awesome sound but only for about ten seconds... then one of the ICs (Q1 - 2068DD) started to smoke a bit and then a really scary (And very very loud) rhythmic popping came from my sacrificial Jays.When I tried again about half an hour later even though Q1 had smoked pretty bad, there was sound, again, although I turned it off quickly when I felt Q1 heating up again. All the other ICs are cool to the touch. I thought I might have messed up with the resistors, causing it to be fed too much power for some reason, but then what I do hear before it overheats is balanced (I'm assuming that one channel would be louder if that was the problem?) I triple checked the whole circuit and it's as it should be...
Wai is Q1 being grilled while everything else is fine?
Since my knowledge of electronics is rather limited so I was hoping that maybe one of you pros might be able to help me here... Xoxo...
If it really was just that one IC that smoked then it does sound like a defective device (or a fake part). Replace it with any common dual opamp as a test (TL082, TL072, 4558 etc).
You may want to work through the guide I posted. This would confirm that it was otherwise all OK. There is a link at the bottom of post #1 in this thread.
You may want to work through the guide I posted. This would confirm that it was otherwise all OK. There is a link at the bottom of post #1 in this thread.
Hi, I have bought O2+Odac from headnhifi a couple of months ago and finally had some time to assemble it.
The problem is that I have no sound or noise from the output (Odac conected to pc and selected as default sound output device).
I have measured all the points from the troubleshooting section on nwavguy blog, and all are in range.
I have connected the Odac to P1 header but im not sure if I have to cut the traces from below. On nwavguy blog it seems that I have if I connect the Odac to P1, but I have found a JDSLabs PDF that I have not to cut them if I connect it to P1.
Can you help me?
Thanks
The problem is that I have no sound or noise from the output (Odac conected to pc and selected as default sound output device).
I have measured all the points from the troubleshooting section on nwavguy blog, and all are in range.
I have connected the Odac to P1 header but im not sure if I have to cut the traces from below. On nwavguy blog it seems that I have if I connect the Odac to P1, but I have found a JDSLabs PDF that I have not to cut them if I connect it to P1.
Can you help me?
Thanks
Like I say, I'm not familiar with the Odac but I can't see any issues with trying the input jack. Its either going to work or its not.
You could also try (and remember I haven't seen one) connecting headphones to the Odac output (which will almost certainly be an opamp) and seeing if you get sound. Don't have the headphones on your head, just use them as little speakers to test.
You could also try (and remember I haven't seen one) connecting headphones to the Odac output (which will almost certainly be an opamp) and seeing if you get sound. Don't have the headphones on your head, just use them as little speakers to test.