Are Ground Loops A Myth In An Electric Guitar?
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- čas přidán 9. 12. 2021
- In this video, I will test whether it is possible (or not) to have a ground loop in a passive electric guitar.
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I really am impressed and commend you on (1) testing the hypothesis, and then (2) correcting an erroneous statement that you had made. THAT, sir, is the mark of a superior scientist and craftsman. Thank you.
Very honest video, thank you Chris !! Fact is it happened to me too to find the wrong culprit, you always have to do one fix at a time otherwise you never find out the root cause…
What happens is when your guitar is making noise, and you think it's a ground loop so you rewire it to "fix" it, you have fixed a different problem that was causing a noise by rewiring it. So it can seem like you have fixed a ground loop, when in reality it was probably something like a short or a cold solder joint.
Edit: I just noticed that you said this at the end of the video :)
mate, really impressive that you corrected your previous position, and tested and demonstrated it. Respect!.. and sub!
Also by turning the volume knob all the way down you basically connect both terminals of the pickup to the ground. A Pickup is just several kilometers of really thin wire wound to a coil, so that should according to this "theory" also create a "ground loop" and like WAAAAY worse than 5 centimeters of extra wire would.
Well done on the correction. Great to see you interact honestly with your viewers. Great info
Thanks for posting this video Chris! I am on several forums where this subject comes up repeatedly. It has been super frustrating to hear the "experts" explain their untested facts. I have a degree in electronics and worked for one of the major music electronics companies for years, I have also built and repaired more guitars than I can count. All that notwithstanding, if I suggest that ground loops do not occur in passive electric guitars, the flames start flying.
Why is it impossible for ground loops to occur in passive electric guitars?
@@Music-el7if For a ground loop to occur, there has to be a potential difference between different ground points of the circuit. That cannot happen in a passive circuit. There's a single ground point in a passive guitar circuit, and that's at the output jack. It doesn't matter how exactly you connect the ground from there, it's always the same ground and there can be no potential difference on it.
@Case_ Why can a passive circuit only have a single ground point but an active circuit can? Please explain like I know nothing because I know nothing!
@@Music-el7if There are no active parts of the circuit that could result in a potential difference between two different ground points, and as such there's no current flowing between said points, and no current flowing means no chance of creating a ground loop, and that all means a single common ground point.
But I can't probably explain it simple or well enough, so maybe it'd be best for you to simply look up an explanation of ground loops.
the biggest problem imo with guitar wiring is when the switching of any bonded pickup leads, that require a permanent ground, hence are not able to be switched without causing a problem. Like the cover of a tele neck singel coil or its bridge pup basplate, become disconnected via switch while the pickup coil leads themselves still have one ground and one hot. You have to run a spearate direct to ground jumper from those covers or baseplates if the coil leads are running through switches pots etc. lacking a permanent ground connection.
But you already know that probably.
Many ground issues are misrepresented as loops on guitar forums imo, but the reality is it might as well be a loop... because the sound is bad on most guitars wired wrong.
Thank you for these videos Chris! They are much appreciated.
Much respect to you for testing this and admitting that you were mistaken.
Very well done, Chris!
Very good explanatory video, I am sure it will contribute understanding the ground issue to many of the builders out there.
Thank you !
Thank you for the clarification.
That was pretty funny Chdis. Thanks for the chuckle
Best guitar related channe on youtube! i have learned so much from you over the last years! Thank you very much!
Wow, thanks!
refreshing to see someone be open to learning. subd
Great video(s) Chris - you rock! Regardless of what anyone says, you make amazing effort to help us all, and your videos are indespensible to us new builders. Thanks for clarifying the ground loop thing. The cool thing is, your suggestion to solder a wire from output jack to the cavity shielding (assuming continuity) means I no longer need to solder a jumper wire among pots since housing of the pot now serves that purpose! Less soldering, tidier cavity. Brilliant! Thank you!
A lot of guys don't like to solder directly to the pot housing since the heat can possibly damage the internals.
This is a great video!
Sorry for posting on an old video but here is a thought I just had: is it possible the problem here is the word loop? People see what visually looks like a "loop" pattern in wiring and think oh that's a ground loop but in reality a ground loop is something found in other types of devices and the idea of a "loop" is just a way for electricians to talk about it or think about it.
You nailed it. I’m guilty of that as well.
Hats off to you sir!
Awesome thanks for the video
You should always hardwire your grounds rather than relying on foil or a metal control plate to provide them. If you don't, and a pot or jack comes loose, you can end up with an intermittent ground thatll bee way noisier than any loop. It can be even worse if youre using active pickups/preamp since the battery circuit relies on the ground to work.
In 40+ years of doing this, I have seen exactly 1 ground loop. That was in an 8 string guitar that I built where the 3 bass strings went through their own pickup to a separate output and amp from the 5 treble strings. Other than that, yeah guitars don't have ground loops.
THANK YOU!
I liked this video and subscribed simply for your humility and good nature. I have a feeling I'm about to go down a rabbit hole, and I'm all right with it.
Awesome, thank you!
Copper shielding does not prevent ground loops, but it does help reduce noise in the form of electromagnetic interference. A pickup works as an antenna that picks up electromagnetic interference as noise. Shielding essentially collects EMI surrounding the pickup and sends it to ground, keeping the potential noise out of your signal.
P.S. I owe this understanding to Dylan Talks Tone's CZcams channel.
Good video. Thank you.
Yea, great vid - ground loops can not happen since you are just creating multiple lines to earth, but all within the same passive circuit and potential - a ground loop only occurs with two or more devices, powered, where there is a difference of potential. AFAIK LOL.
Great Video thank you.
You are welcome!
Thanks for the extremely useful videos. I’ve learnt a lot that I haven’t found elsewhere. Your experience is invaluable.
My two cents on this.
Since a ground loop is a cycle in ground connections, yes, a passive circuit can have a ground loop. There are two additional issues: (1) whether a ground loop can produce noise in a passive guitar circuit and (2) where the belief that passive circuits can’t have them comes from.
(1) A ground loop, or any real life connection loop can work as part of an antenna. So it’s not just about the loop, but also about it’s geometry, impedance, relationship to other components and wires, etc. It matters if there’s high gain somewhere in the equipment chain (e.g., overdrive). In short, making a passive ground loop is a bet that could produce noticeable noise increase under certain conditions. But since you don’t get there by purposely designing an antenna inside a guitar, chances are small. It happens, but rarely. That explains why you fixed a passive ground loop. You were not wrong.
(2) Regarding passive/active ground loops, the problem is language. Yes, there is a phenomenon where the way you wire ground may increase noise severely in *some* active circuits. And yes, it’s often called “a ground loop”. But it’s not actually a ground loop. In fact, you can reproduce it with no redundant connection at all (or with them, if you like). It is when both an input ground and output ground of a high gain circuit share some length of wire. Since real life wires are not ideal, output and input grounds are not the same. Nor is potential the same at every point of ground wires. Then, wire acts as a resistor that will have a very small percentage of the signal across it. And when that small percentage of amplified output signal is also present at an input ground wire, not big enough to produce feedback howling, it still is output noise and humming being reamplified at the input, which increases the noise floor (and reduces signal quality, specially if out of phase).
This different from a ground loop, which senses electromagnetic interference. Here the hum and noise was already captured by the input sensor and is just overly amplified because of wiring problems. Since both cases can sound as hum, and both can be caused by connection cycles, they tend to get confused. It also doesn’t help that both can coexist. In any case, while a guitar can be passive, the whole system is not. Small issues in a passive guitar’s circuit will be amplified by the gain stage of the amp or pedals.
Hope it helps.
Let me add a "thank you" to comments. 🤘 (Thumbnail was awesome. 😂) After your comment in previous video about ground loops, I was staring at wiring diagrams, trying to determine different scenario where ground connection may in fact introduce noise into signal (assuming all solder joints good). Internet forums may be a blessing, and often times a curse, haha. I think "ground loop" is a quick way to place blame on problem. Guitar wiring is seemingly simple, but when doing something a little more creative, I really do have to study every electrical path, in every switching position, in every knob position, every coil split, every series/parallel change, and imagine where all those electrons are moving. I think it is fun like puzzle, and your videos help prompt a constructive exercise. Thanks again, as always, for taking valuable time to share your experience! 🤘🤘🤘
As you are using copper foil on any guitar, like I do, wouldn't any component touching the foil be additionally grounded inducing a lot of "loops". As I see it, electrons move in direction of the least resistance. So which way the move shouldn't matter. As long as your phase doesn't touch the ground.
Good time to you, Chris !
We’re having an argument about whether or not to maintain a magnetic orientation between two humbuckers if we don’t want to get an out-of-phase sound.
Separately humbuckers work normally.
Thanks for you vids and good work. 👍
Thanks so much for this! I've been so confused about ground loops - I've been seeing people confidently argue both sides, and it's incredibly helpful to get a real answer + demo!!! I really enjoy your other videos as well!
Quick follow up question... can you still encounter ground loops within your greater signal chain? I know there are products like the Morley Hum X Exterminator out there. Can you experience a ground loop if you have, for example, a pedal board + an amp plugged into the same outlet? And does something like the Morley Hum X Exterminator solve that by eliminating 1 path to ground (say the amp plug), so that the entire signal chain grounds through the other (say the pedal board power source plug)?
Thank you for the video. I prefer grounding all the components in one path, from the pickup to the output jack. I just don't like overcrowding pots with ground wire.
Thanks for bringing this up. Grounding for passive guitar circuits is really about shielding from radio noise. There is lots of noise around us. GROUND LOOPS sound different. Basically, ground loops occur because of the potential difference between the grounding of two separate components. They are quite annoying in the UK, because we have to ground electronics, each unit. To irradicate the problem, you have to get rid of a ground in at least one of the units, and if you don't know what you are doing, you might end up making your equipment a potential killer. We call it "lifting the ground." There are ways of lifting the ground deliberately where you have to do it each time you use the gear. That way, the gear is safe when switched on, but you take it upon yourself to lift the ground. You might be able to create a ground loop on a passive guitar if you took a ground lead from the gear and connect it to the earth/ground of the building. But I'm sure no one is mad enough to do that.
I have this issue with my rack. It's only small but running a guitar preamp in the loop of an FX preamp gives me a weird washing machine hum like noise which is generally masked by the noise gate. It does slip through occasionally though and annoys the hell out of me. When I bought this guitar preamp I recall the earth was removed from the plug. SO being I'm UK based also that was the centre plug pin. Needless to say I put it back for safety. But I still need to get rid of this dam hum as I believe it triggers my noise gate to open prematurely and then at high volume and with a lot of gain I geed feedback issues. Ground loops are annoying.
@@RabidGerry Hi Gerry. A hum like a washing machine - great description. Try (safely) removing the earth connection again & see if the hum disappears. If it does, you know part of how the "ground loop" is occuring. Put back the earth connection for safety reasons and now the game is finding a safe way to connect all bits in the chain together. Tell me each item in the chain. Start with guitar, and state each pedal or rack unit and indicate if it is mains or battery. If you are using a four gang trailing socket or more than one, let me know that too. If you use two wall outlet that are separated by several feet or different rooms, I need to know that too. If you wrote all that information down and took it to a music store that has an in house electronics repair person, you could request some their time at cost - to see where to put a "ground lift" - if that is possible. This sort of thing has been done for over 50 years, safely, to remove ground loops. But we could see if we can find the problem via this channel.
If your amp is grounded properly with a three prong cord the shield of the guitar jack, pots and strings are all connected to earth ground via amp chassis to ground.
You are not actually proving there is no such thing as a ground loop. On the contrary, you have created a ground loop: it is a loop in the ground connections. What you have proved is that it doesn't cause the problems people expect. Subtle difference, but the kind of stupid crap people argue over
thanks for the correction here. you made me have doubts for a minute !
I appreciate someone admitting that they could be wrong. 🤘🏼🎸
No shame or crow, we are all still learning. Love your videos
Thanks, One more thing, a false contact grond can be causing annoying noise and it is difficult to detect, I haven't found any video about the issue. Thanks again. 🤘
10/10 for the thumbnail already
Chris, the reason your Les Paul wiring became quieter is probably because you removed an extra wire. It's not uncommon for wiring in a passive circuit feeding high gain amplification to behave as a tuned antenna and pick up stray EMI. By removing that little bit of wire, you detuned the 'antenna' and things got quiet. Also, the way to test for a ground loop is to use a meter to measure microvolts along each parallel ground path. A mismatch creates a ground loop because electrons flow to the lower-voltage side. It is impossible to have a ground loop in a passive guitar circuit for the simple reason that there is only a single ground potential. The myth originated with amplifier wiring (powered circuits) wherein there *can* be a differential in ground potential throughout the power and signal paths. Star grounding does work to solve some of these issues in an amp, but it's unnecessary in a passive guitar circuit. Cheers!
I just took the pickguard off a squier bass (old but just got - so needs cleaning) while watching this video and see that it has a ground loop. Never thought about it. Did fender do that? Maybe was added? Not really good solder job. What about the wire that connects to the bridge? Is that needed? Thanks
Don't the pots and switches also connect to ground where they contact the foil shielding, making many loop de loops?
No, because each and every point in a passive guitar circuit that has continuity to ground is at the same ground potential.
I'm guessing you repaired a bad ground on the Les Paul
Yup been saying so for years. Some context, I have been experimenting with radio and electronics since I was 10 years old (a crystal radio) ham radio at 12, built a Heathkit color tv at 14, my first electric guitar and amp at 16 (Heathkit Harmony Rocket and Heathkit amp) Heathkit Radio Control equipment and test equipment. Took electronics through school. I am presently 70 years old. My point is having built all these projects means you need to service them as well. Creating a ground loop in audio equipment is common. Normally caused by a shared ground by a source creating electrical noise. Although my parents would disagree, guitars do not create electrical noise. Electrical noise can be received by the guitar in a similar manner as my old crystal radio could receive radio signals with no electrical parts. The problem with myths are if you hear something over and over it becomes fact. I learned that from Santa Clause.
I remember Heathkit! Made a crystal radio myself.
If you're talking about the wiring cavity, it'd be better to get the cam closer or to build something new like an overhead cam base.
Good correction! Humans tend to have all sorts of beliefs they don’t necessarily question, and guitar players are right up there with the best of em (I’m still sure strap locks kill your sustain!). Appreciate that instead of digging your heals in you tested whether you were correct and went with the results. Appreciate even more that you shared them.
Every time I watch a video on your channel it shows I'm not subscribed, and without exaggeration I know it's been the last fifteen times in a row now I've resubscribed!.. I have no idea why this is happening.
Contact CZcams.
Is there a way to tell if my guitar is properly grounded before I fry myself on a mic?
main reason to shield: ITS FUN! and doesn't seem to hurt haha.
but yeah, if this really was such a big benefit, i feel like more guitars would ship with it as a feature
IT may be possible to create a Circular RF Antenna picking up radio noise.
Funny. And I sort of agree, but I don't think that means you should create them on purpose. Having unnecessary wires and loops could mask cold solder joints and make trouble shooting harder. Especially if one of these extra wires breaks and you have a loose grounded wire floating around. The only thing worse that a problem where you get no sound is a problem where you get intermittent sound.
I recently completed my very first guitar build and it clearly has a grounding issue. It makes a hell of a hum when its plugged in but I’ve noticed it gets much quieter (not silent but pretty quiet) when I touch any of the metal parts of the electronics (knobs, switch, whatever). I neglected to attach a ground wire to the bridge when building it, but other than that it is wired as per the wiring diagram I got.
Could this be an issue with a bad solder joint as it was with the Les Paul, or is it mainly the lack of ground wire to the bridge?
All the metalic parts must be grounded and that starts in the bridge (hardtail with a wire placed underneath it coming from a hole in it's body or a wired solded to the claw in a tremolo system). When I've rewired my guitars I managed the shielding to be in contact even with the screws in the pickguard and the jack plate confirming it with a multimeter. You need to attach a ground wire to the bridge. Hope it helps.
@@TheForce_Productions thanks for the reply. Looks like I’ll be drilling a hole to my bridge!
@@RoadToTheF1 Yeah, you have no choice on that, anyway wire and hole keep hidden. Happy to help, may the ground be with you always! 😁
Hello two things having a degree in very high dollar electronics passive ground loops do exist under specific conditions. Not in humbuckers the magnetic fields strength in humbucking pu's is close to impossible but single coils I found are highly susceptible to loop issues. We know pickup cavities do not require shielding as the shield of the pickup is sufficient. But as the signal reaches volume,tone and blade switches the signals shield strength gets weak due to low magnetic field. Thus shielding of the control cavity or creating another type of shield is important. I've done tests in almost every configuration possible and the results of ground issues were a constant keep in mind the more winfings on pickups does help but sacrifices desired tones. In high powered amp setups the noise was very noticeable . So is it safer to shield the control cavity behinds on components in the guitar. I have done this test on three different makes of guitars with similar results
I would be glad to release the technical information if you would like. Thanks jimmy
Ok great vid. You mentioned the guitar with a ground loop was a les Paul which has two volume and two tone pots Your guitar only has one of each. Now here’s what I’m thinking after looking back at a Seymour Duncan wiring plan for two humbuckers two volume two tone one 3 way switch and 1 output jack. Looking at all the grounds on that diagram the ground goes from each pickup ground to their respective volume pot one ground from 3 way to bridge volume pot then from bridge gets jumped to bridge tone pot along with the bridge ground and output jack ground then jumped to the neck tone pot then jumped to the neck volume pot so now everything is grounded. So now the only two pots that aren’t directly connected with a ground jumper are the two volume pots. Is this your possible ground loop circling around all four pots cuz it’s just traveling the shortest distance to the next ground. You did mention that les Paul had ground jumpers connecting all four pots directly with jumpers I’d like to see you test this theory again on a properly wired les Paul then jump the two volume pots with a jumper see if you get your hum or buzz
So I am planning to install a pre-wired kit into a Explorer. It comes with a jumper between the pots. If I used shielding tape should I add a wire from the jack to the tape?
Ask whoever made the pre-wired kit.
@@HighlineGuitars starr guitar systems
Do you shield your Humbucoer equipped guitars? I was told it kills your high end
You were told wrong. Shielding has no measurable affect on tone. That being said, I don’t shield humbucker equipped guitars.
I also don't understand the idea that you could use braided pickup wire in lp that touches each other then the braid is soldered to their respective pots and they they say don't solder a jumper creating a circle going to each pot. But in essence if you have braided pickup wire touching each other when it enters the control cavity then you have a loop.
Just because it *looks* like a loop does not mean there are two different ground potentials. There can be only one single ground potential in a passive guitar circuit, because the ground potential is identical throughout the circuit. That is what makes a ground loop impossible.
@@thedevilinthecircuit1414 That's what I was getting at. People that say not to make a closed circle when grounding pots together are still making a closed circle with the braided wires toughing. Star grounding is also a waste.
Since the copper shielding is conductive, didn't you already have all your Pots connected together?
Yes.
One point that was not mentioned in any of the comments is that any well-designed piece of audio equipment will have all the ground wires meeting at one single point. For an electric guitar, this should be the ground lug of the output jack. The worst case scenario is having the grounded components connected one after the other and then the last component in the chain connected back to the first component, making a loop. Not only will the loop act as an antenna, but the currents from the various components will be mixed together mixed together in a random way.
If a ground loop is not a case in passive guitar electronic then your point is not valid. You can connect grouds in random places and make redundant connections.
@@zbyszekolko3998 You are correct. "Star grounding" is really a workaround to reduce noise due to ground loops in powered circuits (amps, etc.). In a passive guitar circuit, however, every ground point is at the same potential--so a loop is impossible.
I don't understand! I take an inexpensive Les Paul, from the store - there is noise. I line the foil around the toggle switch and its lid, I line the regulator block with foil and its lid. Connecting all the screens. There is noise. I change pickups to expensive ones without covers - there is noise. I change to nameless ones with covers, there is noise! Now I don't know where to dig? Thanks!
It sounds like there is a problem with grounding. Not necessarily with the guitar, but with the cable/amp/outlet.
When you say a ground loop can not occur in a passive guitar, does that mean that a ground loop can occur in a guitar with active pickups?
Yes, it can occur in an active pickup system because there are various voltages and differing ground potentials within the same circuit. But it's rare because most active systems come as a package (pickups, preamp, and controls) and the maker has already worked out all the bugs. Follow the installation instructions and there will be no ground loops.
It never made sense to me given my knowledge of electronics, electricity doesn't know where it's going, as long as there are 0 Ohms then there's no reason for there to be some issue with simple guitar ground, ESPECIALLY given the fact that plenty of guitars have shielding. All of those pots and the switch is grounded to it by default, almost completely removing the need to run ground wires between any parts. It's an open circuit.
Ground loops are a thing (based on a degree in electronics plus twenty years working in aerospace and mobile telecommunications). If you create a loop of wire, numerous things can cause a potential difference and induce a current in that loop. After all, that's how magnetic pick-ups operate. However, to create a significant ground loop in an electric guitar, you'd really need to connect the machine heads together, converting the strings into antennas. I have not heard on any Luther's doing that!
I connected them with a wire and there was no difference, but i have nylon coated strings-probably doesn't matter, havent try putting noise source
They *are* electrically connected together in most guitars. There is a 'string ground' wire from circuit ground to the bridge. Since the bridge is metal and the strings are metal and they're wrapped on the tuning posts, all tuners are at the same ground potential as circuit ground. The reason for this string ground is to create continuity with the human body; this takes advantage of the capacitance of the human body, which acts as an RFI noise filter.
My loaded pickguard only came with 3 wires to solder: ground to claw in back, ground to output Jack and lead to output Jack. If I want to add copper shielding to my body cavity, how can I connect it to ground without a 4th wire?
Is the back of the pickguard shielded? If so, it should be already connected to ground. In that case, you can run a strip of the copper shielding out of the shielded cavity and onto the top of the guitar's body where it will come into contact with the pickguard's shielding once it is installed.
@@HighlineGuitars Thank you so much dude. Wow. THANK YOU
@@HighlineGuitars THANK YOU!!!
Could it be that the circular ground wiring on the Les Paul was actually creating an antenna? Also, why not connect ground wires to a central connector rather than soldering onto a pot? Is it a matter of, space, simplicity, tradition, or something else? Thanks as always Chris.
Tradition.
Also, one lug on the pot is grounded in order for it to work. The easiest and possibly neatest way is to solder to the case and ground the case.
Having the pot's cases grounded adds an additional level of shielding to the signal path which makes for quieter operation.
wait, so you stand corrected between the loop??? smh I dont know man, I cannot put myself between the pots when I do that test like you are doing imo, not to get a result that is exactly the same as when the ground is not impacted by hands body feet etc.- unless I am floating I guess, or completely out of the equation somehow.
I wonder if soldering or at least roaching the added wire, to create a closed ground back to the output jack not just the pot to sw to pot again looping would help your case? Also curious if closing the cavity creating your FC with the pots all touching the grounded tape changes something. I say then shred on maxed pots into a properly grounded amp plugged into a 3 prong gfci etc and see what happens... at least you are bound to hear the sweet sound of \m/ just make sure you are not barefoot as grounding is all about preventing electrocution imo not tone so much which can be dialed in downstream
Several times that I have heard techs talk about ground loops they were talking about a loop to ground, it's a terminology problem apparently!!!
Dylan talks tone has a video explaining this a few years ago and he comes to the same conclusion as you
Personally, my guitar route, jack input, and master volume are spliced and only grounded to the MV pot in one of my guitars & I don’t have any electrical issues
That's funny, I polished my guitar and the noise went away instantly!
😀
you need to adjust your intro volume big jump from the content volume
Ground loops only happens if you have different voltage potentials to make current flow... none in a guitar.
It’s not a myth the reason nothing changes it’s because electrically all the electronics share a common ground, it’s alll in one node.
Can you help explain how using copper shielding tape that every pot, switch, and jack attaches to does not inherently create a "ground loop", even without any additional wiring? If ground loops were a problem, we wouldn't use shielding. That said, shielding isn't really necessary if you use modern film caps. Shielding was necessary because old school paper in foil caps were essentially RF receivers. I realize that the "old guy" cork sniffers think that paper in foil caps are bastions of tone (because old stuff), but you might want to experiment to see if shielding is even necessary when using modern components.
I have. It is.
wires themselves act as antennas (for EMI and RFI). With mid/high gain amplifiers and pedals, you can listen radio. That's why we use shielded cables to connect pedals, amps, microphones; we are surrounded by RF and EMF all the time.
The "shield" can be a ground plane (in the case of a Strat pickguard for example, it's not "closed", it only works by attenuating the RFI), or a Faraday cage (like the compartment, completely "closed" by a conductive barrier connected to ground)
To work with EMI (from near motors, transformers, some lights, etc.) it must be made of thick magnetic metal (iron and alloys)
Up
Is "crow" really that bad tasting?
Tastes like gamey chicken.
Speaking of myths one thing has really made me wonder: capacitors. Guitar tone controls seem to be built with caps from the 60’s. Today a 50v 0.047 micro-farad capacitor is smaller than a pea yet guitars are built with capacitors used in 60’s era discrete component electronics. I thought values are what matters, not size. Am I missing something here?
You assume caps to be perfect when they are not the farther we go back in time. In guitars and basically all electrical instruments musicians want these imperfections and different responses to different frequency bands while in HiFi equipment this is exactly what you'd avoid (at least design-wise - some "audiophiles" might swear on vintage equipment but that now becomes part of the sound with all the distortions). Those Bumblebee caps Gibson used in the 50s ... god awful caps from a purely technical point of view, but that's exactly what gives them their distinctive sound. It's basically the same with valves/tubes: terrible performance in terms of objective specs but that's also what gives them their distinctive sound.
And it goes even further: those old caps age making their valvue drift like hell. They might have written 0.022µF on it in the 50s or 60s (with a huge error margin probably) - nowadays those caps can even have 10x the capacity significantly influencing their sound. So people mystifying vintage guitars and praising their unique and superiour sound: it's mostly about ageing components being wildly different spec-wise.
While we're at it: pots. A logarithmic/audio profile pot doesn't mean that they all have the same resistance curve. There's a large variety.
Does that mean ACTIVE guitars can have a ground loop?
well, the grounding serves as shielding right? so the foil isn't wasted? It's to prevent your neck acting as an antenna and preventing PC noise etc coming into the guitar? Your test is not really on point I'd say.
Also on the grounding forums I'd bet there is a good chance there are on one side nitpickers who will take a term really literate and those who communicate more on a practical level, so.
The neck can't act like an antenna. The pickups can do that.
That’s not a ground loop. All the pots are at the same ground potential. If that’s a ground loop, than so is your pots sitting on copper foil.
A guitar has a single ground point; at the output jack. You cannot get a ground loop with one ground reference.
What a real ground loop is when you have something like your guitar amp and a PA system. They are each plugged into two different outlets. Then you connect a direct out from your amp to the PA system. If the ground potentials don’t match, i.e., one ground circuit is a higher potential, then current will flow between the ground of the higher potential to the lower potential. This current flowing through the ground circuit produces a loop. That causes a hum. This is why direct boxes have ground lift switches. It lifts the ground on the DI, only leaving the ground on the PA. Now you have one ground.
Your anecdotal Les Paul story doesn’t prove it was a ground loop. I once eliminated a ground noise in a bass by adding a second redundant ground wire from the volume pot to the output jack. Why did that work? Maybe because it lowered the resistance to ground.
Gibson Les Pauls always come with pot cans wired together. They also used to come with the pots mounted on an aluminum plate. That would also connect all the grounds together. So does your copper foil.
But here’s the thing; there’s only one ground reference. It’s all the same.
You are exactly right. I think the term “ground loop” is misunderstood by guitar builders, players, and techs. They see a circle of wires in their control cavity and think it’s a ground loop. Visually, yes, it’s a loop. However, it’s not a ground loop as defined by electricians.
@@HighlineGuitars Yes, but it is still a loop that works as an antenna for all noise from ether. By closing the loop you allow a current to flow and induce noise to the signal ground. It is a loop of a very small area compared to a ground loop in home installation. Your loop is even more eliminated by that shielding-ground plane or a farraday cage, if you close the cover. I prefer not to create loops anyway, as a good habbit, though in a guitar it does not matter that much.
Your volume is very low while speaking and your intro/outro music is very loud
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No such thing as a ground loop. Ground is ground. Electricity travels at the speed of light so it goes the quickest way it can.
until you work with RF, high gain, high impedance, or high currents circuits. Wires have resistance, always. It depends on the context if it's relevant or not
A ground is a common point to equalize different potential energy within a system and that is it. This point can be massive such as the planet or any other large object that the grounded object can sink it's elevated potential energy to. You can have 15 paths to the same ground point and you will not have a loop , just more paths to ground. In the case of guitars to make it grounded then it would have to have a path to earth ground which would not be the case with a wireless bridge. You are not grounding the cavities , you are shielding them from externally generated noise. This requires encasing the components in an EMI resistant enclosure and electrically connecting all shields within the guitar to each other to create a uniform energy level within the system. A classic example of a ground loop in a service entrance would be a subpanel that is not connected to the same bus bar as the panel. Another would be between a branch with a heavily inductive load such as an elevator motor and another branch without this type of load. This can create a "see saw" effect where the different branches introduce a current BETWEEN the branches and not simply from hot to ground. Multiphase loads can do the same thing as well as an incorrectly wired neutral creating a potential between branches in a panel. (neutral is NOT ground).
I think the problem is that people get confused between what an electrical engineer calls a "ground loop" (which is what you have described) and what guitar forums call a "ground loop" which is what is really a "loop in the ground circuit". Let's face it, guitarists have a somewhat less than precise use of language when it comes to naming things ("tremelo arm", ahem).
Now, whether a loop in the ground circuit can act as a better aerial/antenna than star wiring is a different question (to which I suspect the answer, with respect to guitars, is "no").
Great work on the critical thinking and scientific method… yet another reason why Highline is high on the list of first stops for advice. Thanks Chris. (Project_Luthier)
Thanks Troy!