Soldering Pot Backs
This is part 2 of the video series on wiring up guitar electronics.
All the metal parts of the guitar need to be tied to a common ground, including the pot bodies. If you don’t do this, you end up with noisy ground problems. A good place to wire the ground is to the back of the pots.
There’s a few tricks for successfully soldering to the backs of the pots. First up is a hot iron. I’ve tried with a 25w iron, and it just doesn’t cut it. 40w works, but be sure to let it heat up for 10 minutes or so before trying. I use this cheap Radio Shack iron which switches between 25 and 40w. Also, you need to roughen up the surface of the pot to get off any oil or grease, and to give some good grooves for the solder to adhere to – I just use 100 grit sandpaper. Take a look:
Tagged with: Electronics • Video
Filed under: Guitar
I had a question for for in regards to soldering the ground wires to the back of the pot. My project is a Paul Reed Smith SE with one volume pot and one tone pot, both of which will be push/pull pots for series/parallel switching. With a push/pull pot, there is a round section that looks like the back of a regular pot, but the back of the pot where you would normally do all your soldering is occupied by a box that houses the lugs for the switch. I’m wondering if I need to attach the ground to the side of the round part of the pot back or if the attaching the ground the box housing the lugs would work. Here’s a picture of the pot I’ll be working with: http://www.rsguitarworks.net/rsstore/popup_image.php?pID=210&image=0
- Jeremy
By the way, love the blog. Keep it going.
Hi Jeremy,
Good question. That’s a standard Alpha push-pull. The enclosure of the switch is electrically connected to the enclosure of the pot. You can double-check this with a multi-meter- just check for continuity between the pot shaft and that tab, and you’ll find them connected.
See the very bottom of the switch enclosure, there’s a little tab sticking out, under the switch lugs? That’s a fine place to wire up grounds – or you could use the switch enclosure itself if its easier. Just roughen up with sand paper, use a very hot iron, and be careful not to sit the iron there for too long, to avoid damaging the components.
-John
Hey John,
These videos are very helpful – thanks tons. The clarity with which you provide these instructions is impressive. Kudos.
JD
Okay (taking a deep breath) … no fear, just do it! I’m off to the hardware store for some additional tools and materials. With the help of your videos I should be able to get this beauty (Vantage VS696-12, solid electric 12-string with SD StagMag -neck- and Ducncan Custom -bridge-, 2 vol, 1 tone, 3-way toggle, coil split mini toggle and phase switching mini toggle – let’s keep it simple for starters) singing again …
) Thanks for the crash-courses John!
Kees.
(no electro-technical education or experience at all, wish me luck!
Sounds great- Good luck!
-John
… and so she does! (sound good). I made a few mistakes, wired the switches wrong way around, but that was fixed easily, last hurdle would be the tone pot, which is currently working in reverse. Thanks to SD schematics
Thanks again John, for educating me on the basics. I now have the tools and the guts to take on a couple of other ‘projects’ I have lying around. I’ll keep you posted!
Kees from the Netherlands.
Nice work
Mistakes are just a natural part of the process.
Enjoy!
John
@wedel219 – Huh. You should be able to get it to melt! The primary reason to use the back of a pot is that it’s a nice convenient big metal place to which you can solder a bunch of stuff
A secondary benefit is for noise reasons- keeping all the metal parts of the guitar grounded (in this case the pot body and shaft). If you’re giving up on the pot back, you could just use a pigtail instead (an exposed wire connected to a ground point to which you can solder the other ground wires).
by the end of this video, are those wires on the pots which will be the “level 0 volume” and should I add a capacitor instead? what exactly would a capacitor do that is different?
@RocknRollParadiase – In these videos, I’m wiring this circuit using the diagram I posted at my blog at planetz back on 9/21/2009, titled “Riviera P93 Circuit Wiring”. The “level 0″ volume is accomplished on a volume pot, wired as voltage divider, when the pot is turned all the way to the side wired to ground. One side is ground, other side is signal, and the center is the output. Turning the pot adjust the ratio of ground and signal. A cap is sometimes used on a volume pot for treble bleed.
ha anyone every grounded a truss-rod?
@BCGadgets – it doesn’t seem necessary. The truss rod doesn’t make contact with the strings or anything else in the electronics.
I bought a Bill Lawrence single Pickup and I have wired it into my strat.
So I have Bill Lawrence in neck, stock single in mid and GFS crunchy rail at bridge.
I tried to rewire things and solder (first time trying soldering) to help me understand what the wiring is about.
I took black wires from singles and black+silver from GFS, tinned them together and then soldered them to a ring tongue terminal. On another spot on that ring I soldered the black wire ground coming out of the trem cavity. I then took a piece of wire (I covered it with electrical tape) and soldered it to jack ground and to that ring. I had trouble with the black GFS wire – it is very thin. But I think I sandwhiched it between the other thicker ground wires good enough to make the ground connection.
I tested and I find that the neck pickup is working good – no noise
All other positions work with some noise (which sounds sorta like a cracked hum)
Except for the bridge position which barely has output and has same noise.
I also find that the tone pot is not working at all for any position
Do you think I killed the tone pot by overheating? or do you think it’s just a ground connection problem?
I appreciate any help you can provide – thx
Hey Manny,
I apologize for the delay- I somehow missed your comment in my inbox “waiting for moderation”.
It is highly unlikely that you killed the pot with heat. Much more likely that you’ve got a bad solder joint or wiring mistake. I recommend you use a multimeter (buy a cheap $5 one if necessary), and use it to check that everything is properly connected. You should quickly find the problem- either an accidental short, or a broken connection.
Good luck!
John
Hi
thx for getting back to me
I think the soldering was bad.
I disconnected the middle pu (I never use it)
and I then replaced the gfs hum with stock hum (just 2 wires as opposed to 4)
Less wires, less soldering (or at least “neater” soldered joints). tested and both work fine
thank you
Hi Manny,
Must’ve been a bad solder joint. Glad to hear you’ve sorted it out.
John
Instead of grounding it with a piece of wire, can you simply bend the lug back and solder it to the body of the pot? Just to save on the number of wires being everywhere ofcourse
@Dazcam – yes, no problem
hi, im planning on getting new pickups for my guitar. when they say its 2,3 or 4 conductor, what does that mean? please reply man
@andykillian – a single-coil pickup has 2 conductors- 2 wires. One for signal and one for ground. A humbucker is really two single-coils stacked together, so it has 4 wires. However, sometimes they internally connect the two grounds together. And sometimes they gang the two signal wires together into one. With 4 wires, you have more flexibility for coil splitting, etc. See my blog at planetz for my articles on humbucker wiring and coil splitting.
@johnplanetz thanks so much, that helped alot
fantastic videos, thanks!
Hi, I tried everything you said but nothing works, I have a 60w iron.
And even worse with the spring hook plate ground wire, please help!
@PanzarMetal – make sure you let the iron heat up for awhile. Add some solder to the iron tip to get it flowing. If you’re still having problems, maybe your iron is simply not getting hot enough (may you need a new one).
@johnplanetz Its hot enough to melt isolation on a wire while tinning a wire.
maybe i should change the tip from a pencil point to a flat one ?
@PanzarMetal – excellent observation. A larger tip will be better for heating up big areas. My Weller has interchangeable tips, and I use the 1/8″ flat tip for heavy work. I only use the fine pencil-tip point for soldering on PCB’s, etc.
@johnplanetz Thanks for the compliment but you forgot to mention one more thing!
I’m trying to solder the part which is held by screws and 4 springs, they take the heat away faster, so the proper way i should do is to take off that part and solder it on a block of wood so there would be less heat loss.
THank you for the tip!
To rewire does the wire have to be stranded or a strip?
@FacingItAlone – solid core wire can be less flexible and more likely to break. It’s much more common to use stranded wire.
How do I know which lug to solder the ground wire to?
@JonsBrain – you need to have a basic understanding of your circuit. Understanding some basic electronics, and looking at some circuit diagrams will help you. There’s some links to resources in the FAQ at my blog at planetz.
I am making my own guitar and am putting in the Zakk Wylde EMG set. It doesn’t come with a 3 way switch or the wires for it, what gauge wires do i need to connect the switch to the
‘B157 EMG pickup buss’ that came with the pickups?
@RuneScapeRoots – 22 or 24 gauge will be fine.
the pots that came with the pickups i ordered are 25k, and the three prongs or legs or whatever theyre called are too small to bend back to solder the volume one
@geohuete94 – I actually prefer not to bend pot lugs to directly solder them to a pot back. I just use a short wire instead.
Hi John, I don’t see any rosin around the solder puddle on the back of your pots in the vid here. I’m having an issue with residual rosin flux around all my solder joints, should I clean this stuff off and if so what should I use? Thanks.
@tulsa9999 – I never bother to clean away the flux, but then as you pointed out, I’m not really getting that much flux build up. if you’re worried about it, you could buy some flux remover spray at an electronics shop
IPA (isopropylic alcohol) removes it just fine usually.
WHAT Gauge solder is best to use or EASIEST to use I should say. really need to know.
I usually use .032″ diameter
Thanks, great demo, totally helped me replace a volume pot!
Cool John : )
I like how you say “pot”
Excellent how-to. Still need to see pt. 1 and 2, but good job.
You say “tin” alot, im guessing solderwire with tin is best for guitar electronics. Great video!
“Tinning” is the process of putting a small amount of solder on the wire before you attach it.ie: you “tin” the wire before soldering it to the back of the pot
Awesome videos, THANKS!!!
excellent videos .. thank you
Hi, thanks for the vid. I had a few questions and was hoping you (or anyone) could answer them.
You roughen up the back of the pot physically so the solder will “adhere to it”. Is this because there is more surface area for the solder to adhere to, or because it removes oxidization and exposes clean metal? If it is the latter, will a drop of flux resting on the back of the pot for a few minutes also do the job?
I’m not totally sure why it works- but I know it does
I imagine it’s a combination of both exposing clean metal and giving more surface area. No harm in trying the flux pen first, and if that doesn’t work well, break out the sandpaper.
Never, Sand the back of the pot! It is coated to accept the solder. If the solder isn’t sticking you haven’t heated the pot enough. Iron is put on the back of the pot near the spot you want to solder. Lay wire to be attached in the pot. When the pot is hot enough the solder will melt and and flow over the wire and pot. solder should spread out, if a blob your connection is poor. solder is applied to the piece not iron.
Is this grounding the pot? coz he’s using the tip which is meant for grounding (or at least thats what i heard)
The back of the pot is used as a convenient big pad on which you can solder together ground wires. It also grounds the metal parts of the pot.
Ya know with ALL the wires that are going to be connected why do it this way on the Pot to Back of Pot Ground? Why not just bend that part back and touch it to the back and solder it into position? That is the way I do it. Plus, I have seen plenty of these done by the Chinese and they just use a strip of clean single metal wire to do the job. But, as before when shoving these in and out of Semi Hollows and SUPREMES any Less wire is a good wire ya know?
I’ve seen that plenty of times too, but I’ve just never been a fan of bending back the lug like that. This is a case of personal preference- they’re electrically identical of course. I’d hate to see a lug break off a pricey pot (though I’ve only seen a lug break off once- and it was probably bent back/forth a few too many times).
Yep, I too have seen the lug break off on several older ones. But, not wanting to actually change out a vintage POT I simply solder to a connection point and it always works as long as there is no solder run off. My main objection is simply adding another piece of wire or LOOP that can trap other wires within the body as you are sliding in the remaining parts. Less is always better specially on a Supreme. What a nightmare to upgrade from Chinese POTs to GIBSONs.
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Hey hows it goin im just wondering is it normal for a 40watt iron to turn blueish in the middle and also I heard thqt its not good to sand the back of the pots…is that true?
It’s fine for the iron to change color as it is used. And the tip will get black.
Leave a blob of solder on it when you turn it off to help protect the tip.
I think it’s fine to sand the pot-backs, as I demonstrated in this video.
And also the tip turns black (its a new iron)
Oh okay thanks a lot and also just a queation………I practice tinning wires and it just seems like it wont happen unless I touch the iron with the solder when applying it to the wire (which I know im not supposed to do) but if I dont then the isolation of the wire starts melting so in reality its getting hotter than the wire….. have you ever had this problem? Im a begginer sort of by the way
Adding a little solder to the iron will assist the flow to the wire by adding some flux, but you’re right that you’re supposed to heat the component and let the solder melt to it. You could try a flux pen, or the flux that comes in a bottle. Also, some wire is pre-tinned, which makes life a lot easier
Thank You !!!
I have spent too many trying to do this without roughing up the pots. That was the missing piece of information.
don’t use solid core wire. The reason we use stranded core is that the parts will need to move once they are soldered. Moving solid core wire places stress on the soldered joints and can cause problems when mounting the electronics in the guitar. Unless you’re soldering onto a pickguard, in which case there is less movement, but I’d still use stranded.
Interesting point – I hadn’t thought of that. Your saying that heavy gauge solid-core wire doesn’t bend as easily, so when you’re moving the parts around, you’re stressing the solder joints?
I’d think that as long as it’s not too heavy-gauge, then it’d still be flexible enough to use without problems.
I guess it’s just common sense- if it feels really inflexible when you bend it with your fingers, you should probably avoid it.
-John