Ground the chassis

[Amitay3333]

Hii
Recently I've built wampler/walrus style pedals that the chassis in them aren't grounded...
Should I ground the chassis? And if so why should I?(from what I saw wampler and walrus didnt do it

[stallik]

I like to ground the chassis on my builds because sometimes it's necessary to cut down noise and interference. If it's not necessary, grounding the chassis doesn't hurt and, at the end of the day, it's one wire.

If you have a pedal with no obvious ground, check whether metal jacks are performing that function.
Also, daisy chaining to other pedals might introduce one

[amptramp]

If you have a grounded pedal and a grounded amplifier, you may find a massive hum caused by ground loops, especially if they are not plugged into the same outlets.  I would ground the amplifier since it can produce larger fault currents and let everything else be grounded through the audio cables.

If this is not good enough, you should use a ground isolator, usually an audio transformer for signal driven by an LM386 or some similar driver.  The isolator could also be an RF modulator - demodulator pair or optoisolated but should in some way prevent any current from flowing along grounds.

[EBK]

Are we talking about actual earth/safety grounding here, or are we just talking about shield grounding?

[GibsonGM]

Any effect circuit running on low voltage should have the metal enclosure grounded, done by the ground that runs thru the audio cables back to the amplifier input, ultimately.  That ground generally will tie to the amp's earth ground (CHASSIS).   

The currents that eddy in stomps should be so low as to present only a minimal risk of noise - what benefit could there be by floating the effects that's not outweighed by the protection from induced noise offered by a grounded enclosure??

As Eric points out - a true 'chassis ground' is something entirely different and mostly will involve mains protection!   Does the OP have a schematic to post so we can see which connection (or lack of) is the issue?

[Amitay3333]

Thanks for helping! I did connect the chassis to ground and a tiny bit of hum dissapeared  but nothing major...

[GibsonGM]

What you may be avoiding in the future, however, is picking up a radio station, or a buzz that could make you crazy if you took the pedal somewhere near a light transformer or something...   

[pinkjimiphoton]

can't have a faraday cage if its not connected to earth. yes. the chassis should ALWAYS be at ground potential. for safety, as well as audio purity.

[Processaurus]

If the metal chassis isn't grounded it can act as an antenna, pick up noise and RF. High gain pedals especially can suffer. Hum, buzz. It can happen if just part of the chassis is floating, like if the lid doesn't have continuity to the main part of the box because the paint insulates it from the screws. Grounding in audio systems is a deep and fascinating subject, but pedal land is nice and simple, just treat the chassis like an extension of the cable shield, and ground it.

[GibsonGM]

^ This.  Our 'systems' are so simple and run on such low power that, unless there is some complexity in the build (microprocessors/digital monstrosities that most of us never see...), using the old formula of jack switching, PCB ground and LED ground back to one 'star' point is almost always going to be enough to provide pretty noise-free operation that won't also pick up RF and other junk.

I think we can get mystified when we read articles/books about say, amplifier construction - using mains power - that treat the subject very carefully, for good reason in those cases.  Our stuff IS tied to earth ground via the amp, if built properly - grounding the enclosure simply carries this through so that chain is not broken.   At its most basic (think bypass), it's literally just connecting patch cords together thru a metal box with 2 jacks     

[Amitay3333]

Thanks a lot guys!!
BTW I'm thinking on using those SMD parts that connect the GND to the chassis like in the pictures

Here in the left where's the input... what's the name of this spirng? and where I can buy it cheaply(Tayda?)


Or in here this piece of metal in the right near the 3pdt switch, what's it called? and where can I buy it?

[FiveseveN]

PCB mounted battery clips (holders): https://www.alibaba.com/product-detail/Poding-AA-Battery-Holder-pcb-AA_62282655161.html