[Baron5]

Hey guys,
A while back I made a cmoy which i could never get to work, now i have finally got around to rebuilding it since i have been studying electrical energy systems for my degree and though i would be able to get it working. Both times i have seemed to end with the same problem, there is a lot of noise which is not varied when using the potentiometer volume. And also only very quiet music coming for the left channel. I'm not sure what i have hooked up wrong if anything but have got some pictures for you guys to examine. Is it possible that just the wiring of the i/o is wrong? I have checked the v+ v- pins on the chip which are exactly the same with opposite sense, same as the capacitors to ground. (both +or- 4.46).
 

I have soldered the resistors in this pictures underneath the board because of the layout, don't worry about the long leads bent around i know they are not touching anything else i have only left them long because i thought i may have to take them off again to rebuild.
 

 

Please note because of the board i used i had to use a hobby knife to cut and rip up a small part of the tracks in order to isolate the C2 Capacitors for the output. You can seem them here on either sides of the resistor.
 

Just the board so you can analyze the layout better, can understand why i had to cut the track in order to keep the same layout of the cmoy guide.
 
I would greatly appreciate and help. Thanks guys.
 
 
 
 

 

[IMAWolf]

Could be a cold solder joint, i'll use the meter to check impedances over every component, i encountered a somewhat similar problem with my old cmoy build, it was a faulty op-amp.

 

[wakibaki]

Sometimes you (I) build something wrong and then it's very difficult to spot the error.
 
I used to work in a test lab, sometimes you'd set up a test, maybe one you'd done dozens of times before, and you just couldn't get it to work, but when you asked somebody else to have a look, they'd just turn a knob or flip a switch and every thing would spring into life. Everybody would go, 'Mmm, finger trouble.' It's a kind of 'wood for the trees' effect, otherwise called 'being too close to the problem'.
 
You can sometimes break out of this trap even if you only have somebody who doesn't understand electronics to help. You get them to look at the circuit and you talk them through what they should expect to see. Often this is enough for you to see your own mistake yourself.
 
w

 

[Baron5]

Thanks guys. Actually I did take my amp into the lab yesterday but didn't ask any of the guys for help regarding my issue. Using the desktop multimeter i found that there was significantly less voltage on the signal input pins on the right channel. I realized this was because i was using a mono audio cable (Duh) and this was part of my problem, stupid i know. The other thing was if you look at the underside of my proto-board both my input caps were completeley isolated from the rest of the circuit and had not been joined to the op-amp, another stupid mistake. Sure enough after i rectified these issues, the amp works fine. Thanks for the help though guys. A few pictures of my finished amp and cable i put together. Now all i need is a pair of westone 4's or sm3's xD