MCH Posted January 25, 2007 Report Share Posted January 25, 2007 (edited) I'm setting up a 2 humbucker - 2 volume - 2 tone. I'm using the star ground wiring. From the leg of all my pots, p/u, input jack and selector switch I have all the ground wires meet in one spot. The control cavity and humbucker cavities are lined with aluminum tape. Do I need to ground the pot cases to the star point also (via the ground wire coming off of each pot leg)? I understand the pot cases will be commonly connected to the cavity shield by the contact of the stem. From what I read it seems the shielding should not be connected to the circuitry ground. So if I connect the pot cases to the star ground this will combine the shielding and circuitry ground, apparently not good. I would have to isolate the pots from contacting the shield. Am I over thinking this? Is my wiring so far correct without grounding the pot cases to the star ground? any thoughts would be appreciated Edited January 25, 2007 by MCH Quote Link to comment Share on other sites More sharing options...
Sambo Posted January 25, 2007 Report Share Posted January 25, 2007 No. If you're pots make good contact with the aluminium (i'd rather use copper tape.. bit better IMO) then you just need to ground the actual tape. Guitarnuts has a good tutorial on it if you google it. Oh, advice. Not advise. You need advice and you advise another person. Ahem. Sorry. S Quote Link to comment Share on other sites More sharing options...
Rick500 Posted January 25, 2007 Report Share Posted January 25, 2007 Must...resist...commenting on "you're." (Just a friendly ribbing. I know it was just a typo. ) Quote Link to comment Share on other sites More sharing options...
MCH Posted January 26, 2007 Author Report Share Posted January 26, 2007 Well I had some ground hum. Whenever I touched something metal it was quiet. I think my problem was that the pots were in contact with the shielding. I stripped everything and isolated the pots from the shielding. I dispensed with the star grounding and am following the Seymour Duncan wire diagram (they should know what they're doing). Haven't had a chance to give it a whirl; need some more shielded wire to go from the selector switch to output jack and volume controls. Hopefully this will work. It's not rocket science, but sure can be frustrating. I enjoy the woodworking much more. Quote Link to comment Share on other sites More sharing options...
Sambo Posted January 26, 2007 Report Share Posted January 26, 2007 Oops. Yeah quite alot of people don't like the electronics bits of making guitars. In terms of isolating pots from the shielding, you dont need to do that. The pot casing SHOULD be grounded, hence why the usual practice is to solder ground wires to the back of the case. Get a multimeter and test it, you'll find the whole of the pot (including shaft) are continuous electrically. If the pot is touching the shielding, then you can just ground the shielding. Seriously... Look at an article on guitarnuts (guitarnuts.com ) called silencing the beast. It's done on a strat, but the pronciples apply to any guitar. S Quote Link to comment Share on other sites More sharing options...
MCH Posted January 26, 2007 Author Report Share Posted January 26, 2007 (edited) The pot casing SHOULD be grounded, hence why the usual practice is to solder ground wires to the back of the case. Get a multimeter and test it, you'll find the whole of the pot (including shaft) are continuous electrically. If the pot is touching the shielding, then you can just ground the shielding. Seriously... Look at an article on guitarnuts (guitarnuts.com ) called silencing the beast. It's done on a strat, but the pronciples apply to any guitar. S Have been to Guitarnuts and read their material. I had all the pot casings grounded individually in my previous star ground attempt plus the casings were grounding to the shield. Still had the hum problem. Hence I'm going to try the Seymour Duncan wiring scheme. I've looked at my other cheapie guitar and it follows the SD configuration and it is dead quiet. Of course I could have done something wrong in my previous attempt. If you don't succeed the first time, try and try again. Edited January 26, 2007 by MCH Quote Link to comment Share on other sites More sharing options...
MCH Posted January 26, 2007 Author Report Share Posted January 26, 2007 Well I just finished rewiring as a Seymour Duncan style wiring and have success. No NOISE!! Whew that takes a load off my mind. Now I can enjoy the woodworking of my other guitar in progress. It's all a learning process. cheers Quote Link to comment Share on other sites More sharing options...
GregP Posted January 26, 2007 Report Share Posted January 26, 2007 That's cool-- but something was still amiss that's worth addressing for future readers of the thread. Your shielding should make what's essentially one continuous "surface"... when the pots touch the shielding material they just sort of "add on" to the shielding. Then you need ONE ground that goes from the entire "shielding" to the star. The back of ONE pot makes a convenient spot to solder a wire for sending to the star. Make sure that NO other ground wires touch the cavity or pots (ie. bare wire is covered up) and the star itself is insulated... a bit of electrical tape is all you need. I used an SD wiring diagram as well, but for every "solder" blob (which is just their way of indicating ground) I just modified accordingly and sent to the star. Greg Quote Link to comment Share on other sites More sharing options...
Truth_David Posted February 18, 2007 Report Share Posted February 18, 2007 That's cool-- but something was still amiss that's worth addressing for future readers of the thread. Your shielding should make what's essentially one continuous "surface"... when the pots touch the shielding material they just sort of "add on" to the shielding. Then you need ONE ground that goes from the entire "shielding" to the star. The back of ONE pot makes a convenient spot to solder a wire for sending to the star. Make sure that NO other ground wires touch the cavity or pots (ie. bare wire is covered up) and the star itself is insulated... a bit of electrical tape is all you need. I used an SD wiring diagram as well, but for every "solder" blob (which is just their way of indicating ground) I just modified accordingly and sent to the star. Greg Greg, what happens then in the case of very small pots - I just ordered dual concentric pots to use as a combined volume and tone pot - there is nowhere on the casing to apply solder, and if you did it would most probably damage the pot? When I ordered them I had no idea of the physical size. I have managed to get one working after literally hours, because my guitar has wiring for an HSH configuration that does not follow any wiring schematic I have been able to lay my hands on. The guitar is an Ibanez Prestige USA custom, but considerably older than the only model that comes close on the Ibanez site, which is an early 90's s540, which does not have the same 4 conductor coding for the wiring. On the IBZ F1 and F2 humbuckers, mine had red and white hot wires from coils 1 and 2, and black and green cold wires. Green went to earth, black and white are soldered together, and the red wire goes to the 5 way selector switch. But the confusing part was that the single coil in the middle position had 3 conductor wiring - two black wires and one red. The red goes to earth - duh! while the black goes to the switch! That left me with another black wire which also goes to earth. Once I worked all that out, I had the pickups all working without noise (the guitar is still not strung up as I am awaiting a delivery of stuff, so I cannot check on the phasing). Incidentally, I also tried to use the star wiring diagram on the page you mentioned, but found that the earth wires that originally were soldered to the pots could not be on the same ring as the rest of the wires that go to earth. But as soon as I made a secondary earth connection for the earth coming from the trem arm and another for the earths from the pickups, no noise. I also wired a capacitor in line between the trem earth wire and the earth lug of the jack, as recommended to avoid shocks. The next thing I want to do is wire the 5 way selector so that I can select both humbuckers, or possibly even also split each one and combine the two outside coils, like that special combination a normal Strat cannot access.... can you please help? I intend replacing the tone control that is now combined in the concentric pot with a push-pull switch - I know it is pointless to have removed the tone control, as I could have simply combined it with a push/pull pot, but I was experimenting, and have not thought of any better way so far to use the concentric pot and this guitar only uses two pots, one vol and one tone.....and I am unwilling to drill any holes for a DPDT switch. I also ordered a 12 position switch with 4 circuits, but I have no idea how to wire it into the circuit. What was complicating the issue somewhat is that the Ibanez switch is not like any switch I have ever seen. Actually, it is a little easier to work with once you understand the layout: it has all the 8 circuits combined in a linear fashion, apparently all on one side of the switch, and it took some time for me to deduce that the first 4 relate to the left 4 on a wafer switch, and the second 4 to the other side. But it really got me confused for a while . I would really appreciate any help you can offer, thanks. David Quote Link to comment Share on other sites More sharing options...
GregP Posted February 18, 2007 Report Share Posted February 18, 2007 I can't tell what the question is. Sounds like you got things mostly under control, no? As for the dual cocentric pot, you can always just let that one touch the shielding material and not have a ground coming directly off it. You only need one ground lead coming from the "shield" (the entire surface, including the pot shells) so you can always take it from another pot or from the shielding material itself if it'll take solder (aluminum foil won't). Greg Quote Link to comment Share on other sites More sharing options...
Truth_David Posted February 27, 2007 Report Share Posted February 27, 2007 I can't tell what the question is. Sounds like you got things mostly under control, no? Thanks Greg, yes, sort of.....what I ended up doing was fitting a push/pull switch which just serves to add the neck p/up to any of the positions from 3 to 5. And it makes a tremendous difference, because there are now so many sound options. My favourite though is both neck and bridge humbuckers on together, like the middle switch position on a Les Paul or similar. I was pleasantly surprised, and I also wired in a treble cut cap and resistor circuit so I don't lose HF when turning the volume control down. I have another push/pull switch I am not using, and am wondering what other p/up combination I could use it for - I am not into out of phase switching, but perhaps series/parallel? As for the dual cocentric pot, you can always just let that one touch the shielding material and not have a ground coming directly off it. You only need one ground lead coming from the "shield" (the entire surface, including the pot shells) so you can always take it from another pot or from the shielding material itself if it'll take solder (aluminum foil won't). I used a variation of the Star grounding circuit, and soldered everything to a collar under the push/pull pot, then to a 400v capacitor between the vibrato clasp and the ground. So far it is dead quiet, even though my house has a dodgy earth .... BTW, have I seen you on the Sustainer thread? David Greg Quote Link to comment Share on other sites More sharing options...
GregP Posted February 27, 2007 Report Share Posted February 27, 2007 I have another push/pull switch I am not using, and am wondering what other p/up combination I could use it for - I am not into out of phase switching, but perhaps series/parallel? Yup, that's what I would use it for. I'm not good at wiring diagrams, though-- I always have to call in the knowledgeables when I do my own wiring. I used a variation of the Star grounding circuit, and soldered everything to a collar under the push/pull pot, then to a 400v capacitor between the vibrato clasp and the ground. So far it is dead quiet, even though my house has a dodgy earth .... BTW, have I seen you on the Sustainer thread? Sounds like the way to do it. My apartment has a dodgy earth, too, so I had the landlord retrofit it with ground fault detecting outlets. If there IS a ground fault, it will shut down (theoretically) right at the outlet. Kind of like having a breaker on the outlet itself, but for ground faults rather than overloads. And yes, you've seen me on the sustainer thread! I haven't a clue what those guys are talking about half the time, but I'm sure interested in sustain devices in general. I get the vague feeling I gave you no help. Greg Quote Link to comment Share on other sites More sharing options...
badsnap Posted March 1, 2007 Report Share Posted March 1, 2007 Just a little info on star grounding. By using the shielding as a ground plane, like the chasis in an electronics box, you ensure that all grounds have their own path to earth. Connect the shield to the ground (from your input jack) and the other ground wires to the shield. When you daisy chain grounds (connect the ground in a row, one to the next) you rely on the previous connection for the integrity of the next. This can created ground loops and not only create noise put amplify it. Star grounding ensures that each ground has a direct path to the device being grounded and greatly reduces the possibility of one device interferring with another because the path of least resistance for the current to any given device is straight to that device. If you only tried the tutorial method once, it is possible that you simply had a bad solder connection which you corrected while rewiring. I have reviewed both methods, and they both should work. In theory that is. Peace...Rog Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.