Fuzz factory (Aion flare)radio interference

[Christoba]

Hello,

I am building an Aion flare (fuzz factory) and I can't get rid of a strange problem.  When I turn the volume down on the guitar with the circuit engaged, I get a crackle and popping and some radio interference.  When the circuit is bypassed, no problems.  Here is a video that I made of the issue:

Any thoughts on what is causing this?

[amz-fx]

I looked up the instructions for the Aion pcb and they are thorough, and you should follow them carefully. The only thing I would consider is to jumper a wire from the In jack's sleeve to the Out jack's sleeve connection. Ground connections must be solidly attached!

The RF is probably coming in the input as the power connections are short and have a couple of capacitors for filtering. If you add a small value capacitor across RPD, then it should stop the radio signals. Try 100pF or some similar value: 47pF, 220pF - whatever small ceramic cap you have handy. If the RF stops then you know where it was getting in.

regards, Jack

[Christoba]

Oddly enough, I connected a jumper yesterday to see if it affected the issue.  There was no improvement.  I'll connect the cap and see what happens.

The biggest issue is the clicking and it only starts when I turn the volume on the guitar down.  Strange.

[Christoba]

I tried the capacitor.  It didn't help.  What is happening is so strange.  When I play, the noise goes down and takes a couple of seconds to kick back on when I stop playing.  I. Suppose that I should make a video.  Note, the input and output make solid contact with the box.

[Christoba]

[robthequiet]

I could theorize but basically it's acting like a compressor, responding to a signal by reducing gain. When the signal fades the gain comes back up, amplifying everything, then when you hit the next chord it clamps down again. Maybe try running it with the Comp and Drive at a lower setting or (experimentally) try changing the value of C3 higher to say 50uF or more to give you a longer release. You can just clip another cap from lugs 1 and 2 of the Drive pot to test without desoldering anything. How does it behave when it's not on the pedalboard?

[amz-fx]

From the video clip, it sounds like a capacitor that is charging up over several seconds.

I can tell you that C1 is oriented backwards on the schematic. C8 is probably backwards too. Could this cause the problem? Maybe.

The FF is a quirky circuit that is barely stable, and pcb layout can be very important in getting it to work right. Grounding too.

regards, Jack

[Christoba]

Rob, thanks for having a look.  Off the pedalboard it is much the same.  I've been tweaking the settings and while it has some usable combos, I feel like there is still way more noise than there should be.  Whatever that means....

Jack, nice catch on the capacitors being reversed on the schematic.  I'll try to trace it out tonight to see if the board has them going the correct direction.  If the Fuzz Face is an unstable circuit, the Fuzz Factory would have to be listed as complete chaos.  Thank you for having a look.  I'll report back my findings.

[aion]

Voltages are low enough that the orientation shouldn't matter - I've seen it both ways. I can't find the source right now unfortunately, but I have a memory of someone doing a thorough test of the voltages and concluding it was better to have C1's positive facing outward since you don't know the voltage of what's coming into the pedal. But either way, I've had hundreds of people build the Flare and haven't heard of this happening before (or experienced it myself), so it's definitely not an issue that is inherent to the layout or the cap orientation. I would keep trying to troubleshoot this specific build.

Have you triple-checked all the component values?