Ground Question - in/out jacks

[Bucksears]

Troubleshooting a little buzz when I'm playing - this is on the Complex OD and Lead Solder OD, but the question is in general - noticed something with the grounding, and I'm wondering if there is some redundancy going on. If so, it could be a culprit for extra noise due to a ground loop?
I know these are high(ish) gain circuits, so some noise is to be expected. I've also read that if there is noise when you let go of the strings (and it goes away when you touch the strings or any other metal part) that it could be a grounding issue with the circuit.
(Could be the pickups - they're Mojotone '59 Clones that haven't been wax-potted.)

I typically only connect one of the jacks' ground lug (input or output) to the board's ground pads, as the other jack will connect via the inside of the metal enclosure.
My question is this: do I need to connect both to ground, or would that cause a loop?

Just running through the options.

 

[jimilee]

Troubleshooting a little buzz when I'm playing - this is on the Complex OD and Lead Solder OD, but the question is in general - noticed something with the grounding, and I'm wondering if there is some redundancy going on. If so, it could be a culprit for extra noise due to a ground loop?
I know these are high(ish) gain circuits, so some noise is to be expected. I've also read that if there is noise when you let go of the strings (and it goes away when you touch the strings or any other metal part) that it could be a grounding issue with the circuit.
(Could be the pickups - they're Mojotone '59 Clones that haven't been wax-potted.)

I typically only connect one of the jacks' ground lug (input or output) to the board's ground pads, as the other jack will connect via the inside of the metal enclosure.
My question is this: do I need to connect both to ground, or would that cause a loop?

Just running through the options.

Nope you don’t need to, nope it won’t cause a loop.

 

[hamerfan]

Check whether the jacks ground lug make a good connection to the enclosure.

 

[giovanni]

You can also just test it? Record the noise floor, then connect both to ground, record again and compare? I recommend recording because our ears may not recognize differences if not A/B-ing.

 

[Bucksears]

Check whether the jacks ground lug make a good connection to the enclosure.

They do.

You can also just test it? Record the noise floor, then connect both to ground, record again and compare? I recommend recording because our ears may not recognize differences if not A/B-ing.

I'll try this, jumpering the ground lugs by hand and see if that's any different. Starting to think it may be the guitar; not touching anything on the guitar is when the hum is more apparent.

 

[pricklyrobot]

If you’ve got a multimeter with a “continuity” setting, you could put one lead on the edge of your guitar’s output jack (i.e. sleeve/ground) and then touch the other lead to all of the other metal pieces on the guitar (bridge, switches, pickup covers, etc) to see if anything isn’t tied to the common sleeve ground.

 

[jwin615]

Sounds like an issue with your guitar or cable. I've seen some cheap guitars skip grounding the bridge for some reason. A friend got a Chinese made Jackson 7 string recently where they failed to ground the bridge. It's crazy that they skip this. I don't know if it's a cost saving step or just dumb design/execution.
I would also check your cables and make sure each sleeve has continuity.
As far as pedals go, there are 2 strings of thought.
1)ground everything. Via box, wire, whatever.
2)only ground the input and isolate the output(ungrounded). The thought here is that the input of the next device after the pedal should be grounded(inputs of any device should always be grounded). The cabling will have a single point of ground contact, thus reducing the chance of ground hum/loop. This is a normal and acceptable practice. Ensuring that a star ground scheme is established where the PSU is the central node. It can also help alleviate ground loops between the amp and pedal chain as sometimes the two devices can end up on different circuits, particularly in live environments.

 

[andrewsrea]

Having one source to ground and using the 'star' technique reduces the likelihood of ground loops.

That said, eddy currents which are exasperated by ground loops, are a condition of mixed metallurgy (copper meeting aluminum, for instance), either different metals or different density (an alloy which its 'ingredients' are not well mixed, due to casting process). Most of the pedal enclosures I've encountered are not cast with precision (visible by 'pits', 'voids' and varying textures).

I always use a plastic Cliff jack for the input and a Switchcraft for the output. Both grounds are connected to the effect circuit, but the Switchcraft is the only link from the circuit to the enclosure.

As for the Lead Solder OD, search this forum for solutions. The design has circuit features which make it prone to oscillations. I have built two so far and have listed changes which preserve the Soldano tone (I've repaired a few SLOs in my day), while preventing the 'hollow whistling' when all the knobs are full up.