Weener Wah - Background Noize?

[luks999]

hi folks

ive a problem, maybe anyone has experienced similar.
i have a increased background noise with the weener wah. the wah works and its sounds great, but theres an increased noise when its switched on.

ive checked the grounding, enclosure is grounded, jacks too.

maybe someone has some dummy tips

thanks

note: its doesnt happen with my other wah

[luks999]

anyone any ideas?
or is it just the circuit?

everything is grounded properly and all the parts are correct.

noise / static kind of thing is increased when turning up the sweep.

could it be a jack, or maybe the enclosure (shielding) ?

[AntKnee]

I just finished mine, too. The only increased noise I get is when my boost is pushed up.

[luks999]

yeah i dont think the boost is noisy but the noise is increased with the boost....

i tried it with a humbucker guitar too (since i thought the single coils may cause the noise), but it occurred too..

dont know what to do here. checked everything through...
any tips? checked groundage already....

[AntKnee]

First thing I would do is check/reflow all your wiring connections on the board and hardware (jacks, switches, etc.) Maybe try a different  power supply, too. Could you post a gut shot?

[the3secondrule]

Transistors socketed? Try swapping them, some transistors are just noisy/hissy, particularly if they've been overheated

[luks999]

i tried BC109B and 2n5088 / BC549 (as in the weener bom).
occured for both tranny types. yes i have sockets in there

i checked the wiring. everythings new though, except that that input jack is old. may the input jack cause such trouble? i guess not, either the connection is there or not.

heres a gutshot:

[luks999]

ok i traced this again, and the circuit seems to be fine

one question before i desolder anything:
i used 2w resistor (metal film) instead of 0,6w resistors for the 470k and 10k
can that cause the issue? is it possible that resistors with more power are noisier?

heres a datasheet
http://www.uk-electronic.de/PDF/Phoenix%20PR02.pdf

thanks for any advice here

the noise occurs before the sweep pot, around the inductor cant locate it any furhter with the audio probe

[luks999]

ok still unfixed
its a static noise at the end of the sweep of the wah pot

i tried following things:
-) different transistors, doesnt help
-) resolder everything, doesnt help

ive read some older posts and maybe i should try the following:
-) the wah pot is brand new --> should i try spray anyway?
-) ive used tropical fish for the 220n caps --> can that be a problem?
-) what can i try? which parts can cause the problem? maybe the polysterene caps?

thanks, i am thankful for any advice here... :/

[jimilee]

First thing I would do is check/reflow all your wiring connections on the board and hardware (jacks, switches, etc.) Maybe try a different  power supply, too. Could you post a gut shot?

This reflow all of your solder joints. After 2 years or so, I still miss occasionally.


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[luks999]

different power supply wont work either
tried to reflow solder joints too
the noise seems to be increased at the end of the sweep pot
maybe something to do with the pot?
ill try a different one or try detox spray
but except from that noise, wah seem to work fine

[madbean]

When you have noise the first thing to do is audio probe the circuit to see where the noise is introduced. You need to check the base and collector of Q1 and the base and emitter of Q2. Since the boost does not seem to cause your noise you can skip that.

FYI: higher wattage resistors tend to have less noise, so I do not think that is the problem here. Until you audio probe, we won't know for sure.

[luks999]

thanks brian

i did a quick audio probe, base of q1 & q2 is quiet, noise appears on the collector of Q1 only
seems to be near the inductor or the sweep pot

should i try chaning the sweep pot?

[luks999]

update: tried a different wah pot, that was not the problem, hum still occurs
its only hearable when you strum a chord and wait some moment, its not permanent pain in the ass noise

[luks999]

update: ok i tried to improve my case shielding, helped a lot
found out the bottom plate wasnt on ground, i fixed this, its a lot better now.
the noise is now at minimum, i think that was the problem