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Got damn buzz! Please help!!

#41
SGD Lutherie said:
In a bass there are no currents running through shared grounds. If you do some searches on TalkBass and other places, people who do the GuitarNuts star grounding thing often have more noise after the mod than they started with.
Click to expand...

Everything you say is true, but I doubt that doing a star ground will give you MORE hum. A number of manufactures do a star ground just for drill even though it's not really necessary (usually a wood screw into the conductive paint somewhere that all ground wires go to). And even a wire run down the back of the pots that are all mounted to aluminum foil or a jazz control plate in essence makes a "large" star point for grounds.

Basses and high gain mic preamps (where star grounding stories come from) are quite different things.
 
#42
bassbenj said:
Everything you say is true, but I doubt that doing a star ground will give you MORE hum. A number of manufactures do a star ground just for drill even though it's not really necessary (usually a wood screw into the conductive paint somewhere that all ground wires go to). And even a wire run down the back of the pots that are all mounted to aluminum foil or a jazz control plate in essence makes a "large" star point for grounds.

Basses and high gain mic preamps (where star grounding stories come from) are quite different things.
Click to expand...

I wouldn't think it would give more buzz either, but I keep reading people complaining about the results after they do it. I think some of it is coupled with them doing the guitarnuts thing with the capacitor on the shield. I think the other thing is it produces more complexity than some people's wiring skills can handle. Rather than soldering a ground to a convenient location, they have to run an extra wire. So you end up with more wire for the grounds.

It wire my passive basses exactly as you said; I have them mounted on foil, and then wire the backs of the pots together. That of course is exactly what the foil is doing, so they are in parallel. It's a standard ground buss, or ground plane.

The thing some people seem to have an issue with is the parallel grounds. I've heard people talk about cutting away the foil under the pots when they wire them together, thinking that will prevent a ground loop. In actuality, the back of the pots, and the foil form one big ground plane. Just as on a PCB, you can connect to any point along that ground plane.

As an example, you have the aluminum mounting plate inside the Les Pauls. They used to also run a buss wire across the pots, but this saves on wiring time. The newer models use a circuit board to replace all the wiring.
 

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#44
warnergt said:
Funny. That's the same thing I was thinking when you were
telling everybody that ground loops in a bass were a myth. :rollno:
Click to expand...

They are a myth in a bass or guitar. We can see that Gibson and Fender agree with me too.

Prove otherwise. You have not done that yet.

Your teachers must have loved you in school! :eyebrow:

By the way, drawings don't prove anything. The equations don't either because they don't apply here. Where is the induced current coming from? Are you 16 years old? Because young people seem to think text book examples are real wound examples. The you spend a decade building stuff and you know it's not.

So get your meter put and take some measurements and see if you can prove what you are talking about. And I'm saying you wont.

When YOU build a few guitars, including the pickups, come back and talk to me.
 
#45
warnergt said:
Funny. That's the same thing I was thinking when you were
telling everybody that ground loops in a bass were a myth. :rollno:
Click to expand...

To get a ground loop you need to have some level of voltage difference in the grounds of the power supply going to different components.

Ground loops have become a common myth in guitar wiring due to a misunderstanding of how they actually work. Many people have falsely assumed that if wires are connected in parallel between different components that current will potentially "loop" through them, simply because the wire forms a physical loop. This doesn't happen though, as current does not simply move in circles because they are available to travel through - it needs a motive to go in any direction, and if there's no voltage difference, there's no motive.

Ground loops can occur between an amp and pedals, or a mixing board and power amp if they are plugged in to different outlets, but not inside a passive guitar circuit.

I've built well over 100 electric basses, and my customers routinely commented on how amazingly quiet they were. I never once gave a flip about ground loops or star grounding. David (SGD) is an expert in pickups and has years of experience with guitar electronics. But I guess that doesn't matter to you. Nor do the facts we've presented. Because this is the Internet and your ego is now 100% committed to winning an argument about...ground loops. Really? Ground loops?
 
#46
-=DanAtkinson=- said:
To get a ground loop you need to have some level of voltage difference in the grounds of the power supply going to different components.
Click to expand...

+100

Ground loop noise comes from the power supply, which is why the hum is the same frequency as the mains. Basses don't have an AC power supply. It's a passive component (or battery powered).

Plus, there is no loop. Plug your bass into two different amps at the same time, and you might have the two amps develop a ground loop. Or your amp and the PA. We have all experienced that at one point or another. Or even gotten shocked, which is the same thing. i.e., current flowing through the ground from one circuit to another.

I was building ground lift boxes back in 1974 to stop that kind of stuff. Or you make a cable to link two peaces of gear with the shield disconnected on one end. This is nothing new.

OK I'm done here...
 
#47
SGD Lutherie is correct. Amidst the comedy, I had to chime in. I know all about star grounding, and it's NOT needed in a bass. What is so hard to understand here? Ground is ground is ground is ground is ground, for Heaven's sake. It's simple. Wire all the grounds together and ground the bridge.
I worked as a radio engineer for over 20 years. Try getting rid of RF in an AM-FM studio that's 75 feet from a 1000 watt AM radio tower. There's racks of stuff in one studio, and there's 4 studios altogether. Star grounding will work when all the grounds go to one ground in a star configuration. In this instance, you have many grounds and a lot of ground wire that you can measure a VOLTAGE difference with a meter. I ran 4" flat copper to every studio. It was still tricky.
In a bass? Come on. This is the last GROUNDING debate for me (to chime in on). I'll still read the posts just for the free entertainment, though.
SGC Lutherie, you need to just walk away, buddy! LOL
 
#50
The fact is that the star ground topology in a guitar reduces
susceptibility to noise. It doesn't cost any more to
implement. There is no reason not to implement it. To
actually tell somebody to avoid it (as DanAtkinson's link to
Searcy String Works link does) is a disservice to the guitar
community. It's bad advice, plain and simple.

All grounds are not the same. I provided a link to a document
from the IEEE that agrees. Somehow, some of you guys still
refuse to believe. I showed how it can happen. Without
being able to identify any specific problem with what I
showed, you still don't believe. You can't make a rational
case to not use star grounding other than "I don't think you
need it."

Whether or not star grounding works is not decided by a small
democratic vote. Just because I'm surrounded by a few
flat earthers here doesn't make it wrong. There are many,
many guitar builders who insist it works. If you go over to
the gearpage.net where guitarists hang out, the overwhelming
consensus is that it works.
 
#51
warnergt said:
Just because I'm surrounded by a few flat earthers here doesn't make it wrong.
Click to expand...
The irony.......
Warner, you're wrong. The drawings you made are........ wrong. The documents you linked aren't relevant.
There are no circular currents in a guitar, as indicated by your little 'antenna.'
Doesn't happen, doesn't exist. Yes you have an EE background and yes, you are wrong. It happens.
You've been asked to get out a meter or scope and demonstrate your theory. You haven't.
Guess what? It doesn't matter!!!!!
I kindly suggest you let it go.
 
#52
warnergt said:
The fact is that the star ground topology in a guitar reduces susceptibility to noise.
Click to expand...

Yep. It's a good thing every component in a guitar\bass is grounded at the output jack, so it was already "star grounded" at the factory.

warnergt said:
It doesn't cost any more to implement.
Click to expand...

It costs time and effort.

warnergt said:
To actually tell somebody to avoid it (as DanAtkinson's link to Searcy String Works link does) is a disservice to the guitar community. It's bad advice, plain and simple.
Click to expand...

:rollno:

The point of the article was that your guitar/bass is already star grounded at the output jack. Therefore, spending time & effort on implementing star grounding is redundant and unnecessary. Doesn't sound like bad advice to me.
 
#54
Some jazz bass pickups are not reverse wound ... most are ... if you have one of those jazz basses with 2 pickups that don't cancel each other then it will suffer from 60hz single coil buzz.

I got a set of jazz bass pickups off of ebay years ago and both were essentially bridge pickups. The neck was not reverse polarity and not reverse wound.

Also I don't believe the ground loop myth either ...
 
#56
warnergt said:
Yeah, guitars never pick up noise, do they?
Click to expand...

Sure. But if all the metal parts that are likely to pick it up are securely grounded to a ground plane of any shape or size, all of that noise will follow the path of least resistance, which is to ground. It all ends up at the third lug of your power cord, which is what the - terminal of your guitar cable is attached to. Ground. Down the drain it goes, unless something is faulty. It doesn't go round in circles. It goes to ground.
 
#58
warnergt said:
Yeah, guitars never pick up noise, do they?

Do you guys shield your guitars?
Why would that be necessary if noise currents can't get into your guitars?
Do you instruct everyone you meet to stop shielding guitars, too?
Click to expand...

Just asking here, but by your logic the shielding would just act as a bigger antennae, wouldn't it? I mean, the shielding all has to be connected to the ground.
 
#60
dmusic148 said:
Sure. But if all the metal parts that are likely to pick it up are securely grounded to a ground plane of any shape or size, all of that noise will follow the path of least resistance, which is to ground. It all ends up at the third lug of your power cord, which is what the - terminal of your guitar cable is attached to. Ground. Down the drain it goes, unless something is faulty. It doesn't go round in circles. It goes to ground.
Click to expand...

So, now you admit metal parts pick up noise currents when
you said they didn't exist before. Your statements are at war
with themselves.

And when your "path of least resistance" includes the path
that carries the bass signal, you're going to see a voltage
from that signal. Anybody who knows Ohm's law can't
deny this. It's basic electric theory.

You're contradicting yourself and you don't even have the
capacity to see it.
 

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