SOLVED Does slowly building noise indicate a specific failing component?

[Caldo71]

Hey guys, so…

I have this Golden Falk that I built, and it sounds great…FRIGHTENLY like a real Plexi…but it has this funny specific issue:

It sounds perfect for about seven minutes of play through, and then this random crackling noise starts slowly entering the sonic landscape….first very faint in the background, then eventually becoming much more loud and prominent over the next few minutes.

Mind you, the overall tone of the pedal never degrades…it still sounds great…but it becomes unusably crackly/noisy.

So then if you power it down, and wait a few minutes, then power it back up…same thing. Repeatably, every time.

I’ve carefully re-flowed all the solder points just to make sure, and swapped out some of the “easy” components like the 3-way switch, pots, and tried swapping out the J201s which are socketed. Same thing still happens.

Before we get into the whole “show me photos of your build” thing, I’m just curious: does the fact that this issue seems to go away after the power is cut…and the pedal left alone for a few minutes…imply a specific kind of component failure?

From the very little I know about the mechanics of passive components, this sounds like a “capacitor thing” since they are supposed to slowly drain their charge after powering down…but maybe I’m being ignorant.

Thoughts?

 

[carlinb17]

it sounds like a cold joint that when it warms up it is failing... to me anyways....

 

[fig]

+1 to cold joint

Are your voltages reading close to the posted values?

TRIM 1 P2 4.6V
TRIM 2 P1 5.8V
TRIM 3 P3 5.5V

 

[Drayve85]

I’ve been having a similar issue with a couple pot and kettle builds, vero and pcb. I’ve reflowed all solder joints multiple times and that didn’t help. I finally got one pcb board working, and one vero board ‘kinda’ working. On the vero, I moved a capacitor around one time while it was crackling, and it seemed to help. So I’m thinking it could be a capacitor problem also. I haven’t dug into it yet to confirm tho. Maybe try replacing all electro caps first. Just an idea.

 

[jwin615]

Are you running a tube amp? Sure it's not a redplating tube?

 

[Caldo71]

+1 to cold joint

Are your voltages reading close to the posted values?

TRIM 1 P2 4.6V
TRIM 2 P1 5.8V
TRIM 3 P3 5.5V

Yeah my voltages are right on the money.

I’ve been having a similar issue with a couple pot and kettle builds, vero and pcb. I’ve reflowed all solder joints multiple times and that didn’t help. I finally got one pcb board working, and one vero board ‘kinda’ working. On the vero, I moved a capacitor around one time while it was crackling, and it seemed to help. So I’m thinking it could be a capacitor problem also. I haven’t dug into it yet to confirm tho. Maybe try replacing all electro caps first. Just an idea.

Hey @Drayve85 is there any particular reason to suspect an electro versus a “regular” metal film cap as the culprit, to the best of your knowledge? Obviously those are easier to desolder so it’s a tempting answer.

 

[Caldo71]

Are you running a tube amp? Sure it's not a redplating tube?

Nope it’s all solid state stuff.

 

[Drayve85]

Yeah my voltages are right on the money.

Hey @Drayve85 is there any particular reason to suspect an electro versus a “regular” metal film cap as the culprit, to the best of your knowledge? Obviously those are easier to desolder so it’s a tempting answer.

Sorry, I should’ve specified!lol the cap I moved around was an electro, that’s why I suggested changing the electro caps. Sometimes my fingers type faster than my brain can tell them what to type.hahah or the other way around.

The pedal I’m talking about is weird. Everyday when I turn on my amp and pedalboard, I turn on that pedal to see what ‘mood’ it’s gonna be in. Is it gonna crackle or not. Most days it crackles, but it’ll go on these binges where it works fine. I’ve been putting off digging into it.

 

[ReinoutVrijhoef]

Do any of the components in the pedal get hot? Does it exhibit the same behaviour if you take it out of the box and play a while?

 

[ChrsGuit]

Are you running a tube amp? Sure it's not a redplating tube?

Or an overheating solder joint... I have a JCM2000TSL that had the common "rectifier" issue... where the amp would warm up, play great, then sound like you gently turned the volume down... after a few moments, it would come back, wash, rinse, repeat... Same with my Fender Blues Deville and the usual ceramic resistors that overheat and desolder/damage pads on the pcb...

 

[zgrav]

maybe your pedal is fine as is. are you running multiple pedals on one power supply? have you tried a different power supply to see if you still get the noise?

 

[Caldo71]

it sounds like a cold joint that when it warms up it is failing... to me anyways....

So I re-flowed all my solder joints as-suggested and also replaced the two 100u electros as-suggested by @Drayve85 and IT WORKED!!! Played it for 20 mins with no degradation!

Gotta tell ya, thus far have not had nearly enough of these success stories of curing a broken circuit since I began this hobby, so this was really inspiring.

I’m fairly sure it was the expansion of the cold joint under the influence of the pedal heating up compromising the connections as @carlinb17 had suggested: I smeared a f$&kton of solder paste over the whole bottom of the pedal and reflowed every point. This reflowing of everything with lots of flux was a brand-new thing to me but now I realize it should not have been: once it was swimming in melted flux, all the imperfections became WAY more visible as if under a magnifying glass, so that alone was an awesome experience and I feel dumb I’ve never done it. There was a bank of four resistors in one place that seemed to very clearly show some cold joints, but without the flux glop it was not NEARLY as obvious.

I feel like moving forward this is just gonna be S.O.P. for me—a normal step in the process right before I add on all the peripheral parts. Love it.

Seriously makes me wonder how good my percieved-as-very-tight soldering skillz really are, and how many cold joints secretly lurk on all my builds. Tempted to just go do this to everything to make ‘em all super stable.

 

[carlinb17]

Good to hear you got it working!