Humbucker Cover Issues

[Firebird211]

The page Cagey laid down best describes the basic theory behind the volume and tone control in a guitar.  At the heart of electrical theory the source, whether it's a battery or guitar signal, is drawn to the return to complete the circuit.  The return could be the negative side of a battery, or the ground of an entire circuit.  The guitar pickup is like a mini generator, where the vibrations of the string in turn induce a current in the coils, which is an electrical interpretation of the sound.  The hot end of the pickup wants to go back to ground to complete the circuit, and no current can flow unless this connection is made.  If the pickup has easy access to ground without a resistor, such as a volume pot in the way, the circuit is still operational, but you will never hear anything at the output.  Think of it this way, take a 9 volt battery, across the leads you will measure 9V because there is a very large(open) resistance between the two leads, but nothing is flowing until something is placed across the leads.  When the battery is measured the meter has an internal resistance that allows the current to flow to determine what the voltage is.  If you short the leads out, or like shorting to ground, other than the battery getting really hot you would not be able to measure the voltage across it anymore, that potential difference between the two leads does not exist anymore.  The output jack of your guitar is similar, but the signal voltage isn't like a DC battery, but the electricity behaves the same way.  If the resistance is there between the two leads, like 500k down to the smallest setting you can hear, there is as much voltage across the resistance according to that.  You are hearing the voltage amplitude of the signal.  You ground it out, and nothing is audible anymore.  You could think of it in terms like the signal is just pushing it's way through and into the amp, but internally the pickup is really just keeping to it's own complete circuit, and the amp is taking the small signal(sample) and amplifying it.  Just like ohm's law describes it current, resistance, and voltage all go hand in hand.  You can't have voltage without resistance and current.  You can't have current with an open circuit, but what ever device you hook up, whether a meter or amp, is completing the circuit and using the voltage.

 

[iamdavidmorris]

Just so you know, I've read each of your responses several times, and I think I get it.  Overall status update....  I could probably draw my wiring diagram from memory now.  And I've learned tons.  However, my execution is pitiful.  My wires keep breaking at the solder joints.  This is the Seymour Duncan wire I've cut off from the pickups.  Every time I rewired one, another would break.  This probably has something to do with the fact that I keep unscrewing my push-pull pots from the pickguard so I can see what I'm doing.  After using no less than six kinds of wire so far on this project, I'm having the best luck with solid (not stranded) 26 gauge wire.  It seems like I read somewhere solid gauge wire should be breaking more easily than stranded wire, but it's not been the case with me.  I've ordered a seventh type of wire, as well as some heat shrink tubing.  My thinking is that if I can get some heat shrink around the terminals, I won't have as many breaks.  The downside is that if I do have a break, it will be harder to see.

Incidentally, my technique has been to thread the wire through the hole in the middle of the terminal, bend it back in such a way that it sort of holds without solder, then solder, using what I believe is a small chisel or screwdriver tip on a 40w iron.

Thoughts?  Is this a learning curve, or something I'm doing wrong?

 

[Cagey]

You're doing it right. The problem is you're handling the stuff so much that the wire is getting work-hardened. Once that happens it becomes much more brittle and breaks easily. Some wire/cable designs use various tricks to allow for a lot of movement without hardening as quickly, but it generally doesn't lend itself well to "hook-up" work. Sometimes there are strands of other material (plastics, glass and other fibers) mixed in, or the copper is alloyed with other metals to change its ductile/elastic properties. Either way, while that makes for more flexible wire that doesn't break as easily, it makes the stuff difficult to work with or solder.

I'd suggest you assemble the parts, and leave them that way as much as is possible. The wire will see a lot less flexing that way, so it won't become work-hardened as easily.

 

[Firebird211]

I like to use the heat shrink as well for the long term benefits, like helping reinforce the hold and keep strain off the connections, as well as prevention of shorts from other wires, and vibrations from the guitar over the years.  What I usually do is twist the wire tip after it has been stripped to a slightly longer length.  I dab a tiny amount of rosin on it using another wire or a paper clip, then I apply a bit of solder on the tip of the iron and start touching the wire.  The rosin really pounds the solder into the wire tight.  I take the wire and bend it into a hook shape, then use a needle nose pair of pliers to run the hook through the terminal then clamp it on.  The end result is only long enough to have some metal slightly exceed the terminal, so you don't melt some insulation in there too. Of course the piece of shrink wrap has already been put on the wire and pushed back to avoid the heat.  The terminal gets a small dab of rosin too.  Then I do the same thing to the terminal, you can meet the solder to the iron, or just dab the iron first like I do, since it keeps one of my hands free.  That connection is held physically with the wire tight, and even tighter with the solder, and even more reinforced by the shrink wrap.  That always works great for me, as I methodically do that to every guitar connection.  Some folks don't believe in the power of a little solder rosin, but I can't imagine doing clean work without it.  You don't ever have to use very much.

 

[iamdavidmorris]

Thanks guys.  That's encouraging, and I suspected as much.  Next time I'll try to figure out how to leave it all in place a little better.  BF, do you mean something like this?

http://www.amazon.com/Alpha-Metals-AM51024-Liquid-Rosin/dp/B002YM0HN2

 

[Firebird211]

Thanks guys.  That's encouraging, and I suspected as much.  Next time I'll try to figure out how to leave it all in place a little better.  BF, do you mean something like this?

http://www.amazon.com/Alpha-Metals-AM51024-Liquid-Rosin/dp/B002YM0HN2

That should be just fine, the stuff I use is just from good old Radioshack.  Keeping the components in place  and not moving wires around a lot is even more important, for sure.  It depends on your skill to solder, but it is best to have the components mounted into place in the guitar or on the pickguard, and wire from there.  If things are in an awkward position to get to, you could always for example solder the push-pull switch wires, and leave them long enough to be striped down and soldered. The short jumpers that are just on the same switch can be done in advance, and if another wire is to be soldered to that same terminal, do both wires and leave the other wire long enough to get where it is going next. You will learn in time to think ahead a few steps to prevent soldering yourself into a tight corner, where the next connection is more difficult than it needs to be because of the last few connections you just made.  The negative outlook on the use of rosin flux is associated with the use of acid flux, which is way more corrosive.  Using a bit of flux will eliminate how much time you spend heating a connection, and the solder will go right where you want it to go and form a strong connection the first time.  Since you already soldered, and possibly desoldered some of your connections it's a bit pointless to use the flux.  You can still do magic on tinning the ends of wires, but the terminals should be fresh, unless the solder is having issues sticking.  Flux is already in the solder, but you can hardly ever get it to condition the surface you are soldering because it keeps boiling out and away from the thing that you are soldering.  I have found that Flux is, however, pointless on a PCB because:  1. Gravity is on your side, and 2. Solder sticks to the traces just fine by itself.  I have had some uses of Flux on very small electronics, like broken pins that let me solder a lead on a gnat-sized point, where by normal means everything would of gotten torched. Good luck to you sir.

 

[Cagey]

You will learn in time to think ahead a few steps to prevent soldering yourself into a tight corner, where the next connection is more difficult than it needs to be because of the last few connections you just made.

That's a good observation. Plotting and planning can save a helluva lotta work later.

 

[iamdavidmorris]

You will learn in time to think ahead a few steps to prevent soldering yourself into a tight corner, where the next connection is more difficult than it needs to be because of the last few connections you just made.

That's a good observation. Plotting and planning can save a helluva lotta work later.

So can repetition.  This will be the third time I'm wiring this thing.

 

[Cagey]

It's not repetition. It's a practice. You're like a doctor! <grin>

 

[Firebird211]

:laughing7:  You don't need to write a full itinerary for the damn thing, just think ahead a few steps, that will reduce the "I wish I didn't just do that, now what" scenario.  Soldering does take quite a bit of practice, and patients.  The only thing prescribed is beer, or your choice of relaxation treatment.

 

[iamdavidmorris]

UNBELIEVABLE!!!!!


It works.  Finally.

I couldn't have done it without you guys.  Thank you for not only helping me complete the project, but teaching me the skills as I struggled through it.  It's not a Warmoth build yet - not until my birthday next month, when I'll be putting a Warmoth neck on it.  Then a Warmoth body.  Then piezo saddles.  Then a synth output.  Too many controls, Cagey.  I know.  According to my count, it already has 69 positions ( :headbang.  But I hate switching guitars in the middle of a show.  I'd rather flip a switch, even if I'm the only one that understands how it works.  Besides, it's been fun.  

Cheers!

ccasion14:

 

[Cagey]

Good for you! I'm glad to hear that's behind you. Now you can get down to the real point of the whole exercise - rompin' and stompin' at obscene sound pressure levels <grin>