Hey guys this is my first post here seeking advice :) not much experience with pedals building but so far i've build 20-30 pedals mostly for me and some for my friends. To the point...i've build a v1 boneyard for a friend we tested here at my place after i've done with wiring with a crappy psu and sounded awesome no oscillation or anything also we test it with a one spot aswell. The guy called me today and told me that he has a whistle issue like the one we get from bad psu so i told him to try it with a one spot and to check for bad grounding in the wall plug, he told me he test it in 4 different areas ( 2 studios and 2 rooms at his place) with 3 different psu's and it does the same. for reference i've build 4 of them with suggested part value except the crunch pot which i used 100k log, the high gain pot that i used 500k pot and shielded wires to input and output. I still believe that is a bad psu issue bad if you have any ideas on what else i should look that whould be a great help.
thanks
Harris
Still doing it while just being powered by battery?
I doubt but i asked from the guy to bring to my place along with the psu's he used to power it to check it here that i know i don't have ground issues or anything that could cause a problem like that. will post again as soon as i check the pedal :)
thanks for replying.
Stick any buffered pedal in front of it. Then you know if its the notorious circuit whine/howl.
forgot to mention..he told that accidentally he put a reverse polarity psu the first time for 10-15 secs.
Quote from: harrisxr650 on July 27, 2013, 01:41:52 PM
he has a whistle issue like the one we get from bad psu
Quote from: harrisxr650 on July 28, 2013, 09:18:21 AM
accidentally he put a reverse polarity psu the first time for 10-15 secs.
A whistle issue? Is there only a whistle or is it in addition to the guitar signal?
Is that the right schematic: http://www.madbeanpedals.com/projects/Boneyard/docs/Boneyard.pdf ?
its like a faint high pitched noise and its only a whistle...not an addition to guitar signal.
the schematic you linked its v2 of the boneyard :)
thanks for replying
OK, I see, yes you're right.
I thought this is v2:
http://www.madbeanpedals.com/forum/index.php?action=dlattach;topic=9421.0;attach=6083
But that's Boneyard II.
So v1 is this one: http://www.madbeanpedals.com/projects/Boneyard/docs/Boneyard.zip
OK, check if there's still -9V at pin 5 of IC2.
If the reverse polarity cooked D4 then it probably cooked IC2 next...
Thanks, will check as soon as i have the pedal here. One question, if IC2 is cooked shouldn't be the pedal dead as well? I'm asking cause besides the whistling the pedal works.
thanks again
So there's still the expected guitar signal but also this whistle? Sorry for getting it wrong.
yeap, the guitar signal exist yeah but there is that whistle. maybe after the reverse polarity c10 or c11 went defective? just a thought
Indeed, C10 could be gone if it was forced long enough and after the diode burned.
And that could explain the whistle.
You probably can see and smell it when you look inside.
ok. got my hands on the defective boneyard today. i measure dc jack + with pin5 with my dmm and it reads 18v??!! shouldn't be 9v? and second the whistle is still there even with battery use as well as 18v on pin5. Note that i used a MAX1044 and not a TC1044 as madbean suggest. any ideas? thanks
forgot to mention that i changed Max1044 with a couple of new ones just in case and the problem is still there. also the guy used it with a crappy psu but i test it with 1spot and battery here and still having the same issue.
Quote from: harrisxr650 on August 01, 2013, 05:32:22 PM
i measure dc jack + with pin5 with my dmm and it reads 18v??!! shouldn't be 9v?
No, that's OK: The potential difference between these two points is 9V - (-9V) = 18V.
If you measure against ground (G1, G2, DC jack -, battery -) you will get -9V (black wire to ground, red wire to pin 5).
ok sorry for the noob questions :) i think i need to read more about electronic circuits. i did a check and notice that the high pitch whistle its not affected when cranking the gain either in crunch or high gain its affected just a bit by the volume and a little more with boost. Other than that the pedal sound as it should be. Any ideas?
SOLVED!!! took apart the pedal today and noticed a broken solder in IC2 pin1 socket. repair it and that solved the problem. Its whistling now and a great sounding pedal.
Thanks for any help Kothoma :)
cheers
Harris
Glad you could solve it quickly (and if I was of any help).
Doesn't sound like it was that reverse polarity psu after all?
At first i blame the reverse polarity but after opening the pedal and notice that there is nothing blown or burned or smelly i decide to take apart the pcb and check for something wrong in the traces, like a short on the traces from solder blobs or bad etching ( which i was sure wouldnt find anything as i triple check the pcb after etching and after each solder just for that), after a minute i've notice the crack in the pin 1 ,solder it again, plug it in and it worked like a charm. btw i've put a 1N4007 as a protection diode i think its plenty enough to save the pedal and not blown with reverse polarity, the reverse polarity psu he used was a -9v 2000mA!!!
and also putting shielded cables for input-3pdt-pcbin and pcbout-3pdt-output makes the pedal dead quiet with no oscillation or anything i'm using george L's for almost all the high gain pedals i build and all of them are really quiet.
anyway thanks again