Brian's Guitar from Conception to Birth or How to Build a Guitar in 62 Easy Steps!
57 Solder Away
I’m not going to try to explain all of the basics of guitar electronics here. If you’ve never wired up a guitar before, read up on it first. There are plenty of resources on the web that will get you going. You’ll also want to draw up your schematics first so that you know what gets soldered where. The schematic does not show the exact layout of all the knobs and switches; it more shows the flow of sound in the order the signal travels. There will be many wires crammed into the small cavity, and correcting a mistake might mean unsoldering several other connections to get to the problem spot. You’ll definitely want to try to get it right the first time. As you can see, our piezo acoustic bridge added a lot of extra wires, a couple of circuit boards, an extra switch, a 9 volt battery, and a proprietary output jack. However, a lot of the components came pre-wired which made it a little easier, and the additional tone options were worth the extra effort.
Plug in your soldering irons. I used a 30 watt unit for most of the work, but the 100 watt “flame thrower” came in handy when grounding to the backs of the potentiometers (pots) which require more heat. Install as many pots and switches as you can, and do not overtighten any screws or nuts. Keeping in mind that you will need to get a hot soldering iron to the connection points, orient the pots so that the connection points face a convenient direction. We were able to install everything except the volume pot since ours had a double-pole, double-throw (DPDT), push-pull switch on it with many wires to attach to it. It will be easier to solder the wires to that one before it is installed. If you have a battery associated with your scheme, install the housing and route the wires for that now.
Flip the guitar over and install your pickups. Our guitar had a piezo pickup in the bridge whose wiring had to be routed through the bridge pickup cavity, so it had to go in first. When installing your pickups, loop the wire around in the bottom of the cavity before setting the pickup (as in the center photo above). This will leave you a little safety slack if you cut too much off the other end. Screw down the bezels without over tightening.
Notice the soft towels above and below our work area. Don’t risk a scratch at this point. Our output jack already had wire leaders soldered to it. If yours does not, solder some on now since it will not be easy getting to those points once it is installed. Mount the jack to the cover plate and screw it in. Again, do not overtighten anything; snug is enough; strip it out and your screwed. The middle photo above shows our piezo circuit board wired up which will be installed with double-stick tape to the sidewall of the cavity. It also shows me tinning the wires before they are soldered to the pots and switches. Twist your wires together first, then apply a small amount of solder to “glue” the wires together (this is called “tinning”). Insert the wire into the tab’s hole, apply your heat, and it will pull some of that solder onto the tab and make a good connection. Test all of your connections by giving them a light tug. Our volume/push-pull switch can be seen in the right photo above. A vise-grip helps hold it in place; these things do get hot. We made all the connections first, then installed the switch.
Now that you’ve got all of your hot wires soldered up, it’s time to make sure everything is grounded properly. The three-way pickup selector switch will have a grounding lug on it; connect it to the back of one of the pots. Your pickups will have one or two ground wires which should be twisted together and soldered to the back of a pot. Be very careful as to how you route your wires. If a bare ground touches a hot wire, your signal will take the path of least resistance and go to ground. That will result in a weak sound or no sound at all. The center photo above shows our neat and organized wiring job. Our piezo pickup added some components and complexity to the schematic, but their literature was easy to follow and we were able to integrate it into our system successfully. We can’t do too much troubleshooting now without strings, but you can plug in the guitar and tap on the pickups with a screwdriver. You can check for a signal, test your pickup selector switch, and test your coil-splitter switch if you have one. You’ll give your electronics a full test drive later.