ElectroVibe radio interface and bypass issue

[kleinbergerzam]

Having an issue with my ElectroVibe build. Bypassed sound comes through but is still effected by the volume control. Meaning if I turn down the volume completely I get no signal through the pedal in bypassed mode.

The effected signal works and the sound is great. All controls act as expected. But, I get a ton of radio interference. This gets worse if I touch the top of the C5 capacitor. Going anywhere near that area with my hand causes the noise to increase.

I have sanded the inside of the enclosure to make sure that everything that should be grounded is. I have double checked all of the soldering joints and made sure the speed pots are isolated from the board. I also used shielded wire for the input and output wires.

The radio interface can be heard in both bypass and engaged mode. I’m using a really nice Walrus audio power supply and have many other pedals I’ve built powered by it and none have this grounding issue.

Maybe the circuit isn’t completely bypassed? I’m using the switch board that came with the board. Feeling stumped and have had the board in and out of the enclosure a few times trying to track down the issue.

 

[kleinbergerzam]

Well, got the bypass issue resolved. Removed the breakout bypass board and wired it up to the switch directly. Now it is dead quiet when bypassed and the volume control has no effect on the signal.

The radio interface is still there when the effect is engaged though. Sounds fantastic and the controls work, just picking up a radio signal. The noise gets worse with the lid screwed on and also if the lid or hand is anywhere near that C5 cap.

 

[KR Sound]

Is it a good station at least? I’ve had it happen randomly in pedals, but eventually went away and I’m not sure why. What kind of power supply are you using and how’s the cord and guitar?

 

[kleinbergerzam]

Is it a good station at least? I’ve had it happen randomly in pedals, but eventually went away and I’m not sure why. What kind of power supply are you using and how’s the cord and guitar?

It’s actually some political talk show station which is probably why it’s driving me even crazier haha.

I’m using one of these https://www.walrusaudio.com/products/phoenix-15-output-power-supply-120v-230v-1?variant=27128283459 with some Bill Lawrence low capacitive solderless patch cables. All of my other gear works just fine and I’m testing this in a chain of effects and independently.

It’s got to be something in that C5 area that isn’t right.

 

[KR Sound]

It’s actually some political talk show station which is probably why it’s driving me even crazier haha.

I’m using one of these https://www.walrusaudio.com/products/phoenix-15-output-power-supply-120v-230v-1?variant=27128283459 with some Bill Lawrence low capacitive solderless patch cables. All of my other gear works just fine and I’m testing this in a chain of effects and independently.

It’s got to be something in that C5 area that isn’t right.

Ya that would piss me off too. Wish I knew how to help- I’m not very knowledgeable on RF interference issues, especially when they’re as specific as yours.

 

[kleinbergerzam]

Some progress today on this noise isssue. C5 is indeed a major factor in the situation. I swapped out the polarized cap with a poly box type of 1uf. This dramatically lowered the RF interference. If I listen closely I csn still faintly hear the interference but it’s acceptable. Wondering if the 1uf cap towards the end of the audio section of the circuit would benefit from a different style cap as well. I’ll do some additional testing and see.

 

[jesuscrisp]

I would guess your enclosure is not grounded.

 

[kleinbergerzam]

Maybe I should scuff the edges of the powder coated box? I did remove the finish on the inside where the jacks are mounted. I also scuffed a little here and there but I could remove more paint.