Serendipity Etching - Hiss and Fuzz noise

[George]

I just build Serendipity on an etched board and tested it to see if it works.
***but i put it by mistake in reverse polarity for a few seconds - caps started to get hot and immidiatelly i disconected it.
When i connected it correctly i heard the following

-A bit Hissing even if the power is disconnected
-Drive and Tone seems to work
-Voice squeels at high settings
-Volume on low settings gives a nasty hisss and at maximum the hiss gets overall quiter but i get an detuned fuzzy sound (like a starving fuzz)

I replaced the ic (bb opa2604) in case that was the problem.
and i checked for etching/soldering/pots and polarity faults but everything seems ok.

Is it possible i fried something??
here are some pics
Testing Wiring


Front


Back ( i scratched the flux while searching for a sorted connection so its a bit messy)


Thanks in advance

[George]

OPA 2604 (all pots at 50% if that matters)
i followed the numbers as shwon below (topview)


1. 5.3
2. 5.4
3. 5.2
4. 9.18
5. 5.4
6. 5.4
7. 5.4
8. 0

[selfdestroyer]

OPA 2604 (all pots at 50% if that matters)
i followed the numbers as shwon below (topview)


1. 5.3
2. 5.4
3. 5.2
4. 9.18
5. 5.4
6. 5.4
7. 5.4
8. 0

If you take a look at the datasheet for the 2604
http://www.ti.com/lit/ds/symlink/opa2604.pdf

You will notice that pin 4 should be grounded and pin 8 should be positive voltage. Start tracing back from there. Make a 100% sure you have your positive and ground wires wired up properly. From the looks of your voltage it looks like you have 9.18v running on your ground plane.

Cody

[George]

sorry for being retarted but when taking the volts with the multimeter i used the positive end of the battery as ground so my voltages are wrong. New voltages here.



1.   3v
2.   3.1v
3.   3v
4.   0v
5.   3v
6.   3v
7.   3v
8.   8.9v

[George]

i just finish the second one - identical wiring/pcb/components pots everything but the second one sounds reaaaally nice!

here are the working volatges
1. 4.3v
2. 4.3v
3. 4.1v
4. 0
5. 4.3v
6. 4.3v
7. 4.3v
8. 9v

I have little experience with schematics and debugging - so bear with my posts and my lack of knowledge

Any helpfull tips on how to debug it in comparison with the working one are welcome.

[selfdestroyer]

Don't be to hard on yourself. We all start somewhere and its a continual learning process.

Have you made yourself an audio probe yet? If not, I suggest you make a basic one and learn the basics of using it. It will really step up your troubleshooting game.

Whats cool is you now have a working one to be able to test/compare to the non-working one. Using the audio probe you can follow the audio path on the working one and compare it to the non-working one.

Take a look at Paul's (DIY Guitar Pedals) videos if you have not yet:
https://www.youtube.com/user/chromespherecom/videos

Here is one on audio probes: https://www.youtube.com/watch?v=jWvIfDSxbIk

Another thing to remember, when searching the inter-webs for help, you can search for troubleshooting Zen Drive clones and not so specific as "Serendipity". There are tons of clones and with very little differences. So since they are all based on the same circuit, many people have the same issues with them when populating and will help you trouble shoot yours.

Hope this makes sense. Its barely 9AM here and I have not had coffee yet. lol

Cody

[George]

hahah Goodmorning to you sir

I ll have a look on the videos and the audioprobe. The time here is 22:00 so i guess, thanks for your transatlantic assistance