Bass electronics – Lace connections

Posted by is9582 on March 1, 2015as , , , , , , ,

I finally found a little time to do some more work on my bass, and wanted to share a few things. Where I last left the build, was I’d made up a gizmo to hold the Lace Sensor pickup in place (under a little tension), so I could decide my favorite pickup location. This was cool, and the Sensor comes with wires coming from the pickup, terminating in a rubber shrink-wrap-coated female jack. So, once you plug your 1/4″ guitar cable into the Sensor’s jack, and the other end into your amp (or other similar source) the pickup is live and will detect and transmit sound. This was incredibly helpful, with the pickup placement, as I didn’t need to do anything that is normally required in the electronics end of guitars/basses. Specifically, I didn’t need to drill a path for the cabling, or create a control cavity, install a volume control, or even drill and install an output jack. I had actually already completed a few of these mentioned tasks, as I’d drilled my wire pathway and had created the control cavity. This is one of the few pickups, that I’m aware of, that comes out of the box with this type of setup. To mount the pickup, I used some #6 brass screws that were 1″ in length. I carefully marked two diagonal holes, drilled to the correct depth, and inserted the first two screws. Now that the pickup was secure, I marked for the two remaining holes, and repeated the process. I find it’s much easier to handle the four holes, and their accuracy, in this manner. It’s too easy to have the part shift ever so slightly, during the marking process, when marking all four holes at the same time.

Bass showing Lace Sensor solidly attached with brass screws, and pickup's cable/jack.

Bass showing Lace Sensor solidly attached with brass screws, and pickup’s cable/jack.

Now that my pickup was secured, it was time to move forward with the electronics end of things. I first need to remove the sheathing from the shrink-wrapped output jack, and de-solder the wires, to feed the wires down into the control cavity. I used a small razor knife to carefully the shrink-wrap material, and this jack had some of the toughest wrap that I’ve seen. So, working carefully, I was able to nibble away at the sheath (with the knife) until I was able to completely remove the wrap.

Closeup of Sensor attached, and the jack's sheath cut open.

Closeup of Sensor attached, and the jack’s sheath cut open.

After the wrap was off, I better understood Lace’s use of this material (thought continued in a few lines). When I first saw the uncovered jack, it was somewhat reminiscent to the male portion of the guitar cords. It had a screw-on cover, that completely protected the wires, and the solder joints inside. I examined the jack a little closer and it turned out that the flared tip (where the male 1/4″ guitar cord is inserted) was also screwed onto the main body. With flared tip removed, it left a threaded shaft, with connections for left and right (which you can use for stereo, or for mono) as well as a ground.

Closeup of Sensor's jack, showing the wires still attached, and the long threaded shaft. Red arrow points to the unscrewed  flared tip,

Closeup of Sensor’s jack, showing the wires still attached, and the long threaded shaft. Red arrow points to the unscrewed flared tip,

With this design, I knew I could handle the jack’s installation a bit out of the norm, by feeding it through a 1/2″ hole in the bass. I wouldn’t need to use the normal larger sized female jack, and the mounting plate that attaches that jack to the bass. This is a cool setup! I unsoldered the ground connection, as well as the main lead, and then wrapped the tips of the wires together tightly, with some tape. This will make feeding the wires through the body, a bit easier, since there is less chance their leads will get caught in the passage. Feeding the wire(s) was a simple process, although I could have gone with a drill bit a size or two larger, when I drilled the passage. The output wires on most pickup are fairly small, which is what I originally anticipated, but the Sensor’s thicker wires were so large they almost wouldn’t fit through. If possible, it is better to have all of your parts on-hand, prior to starting the instrument’s build, to limit any potential little hiccups (which this almost became).

I bought a couple of extended shaft Gibson 500K potentiometers, to use as the volume control for the bass. I believe this style pot, with it’s long threaded shaft, was originally made to use in Les Paul guitars, so it would work on their carved-top versions. When I created my control cavity on the bass, I left around 1/4″ of wood between the top and the cavity, which I just estimated while I set the stop on the drill press . I didn’t want to get too thin and have the tip of my bit break through, or even telegraph it’s presence. When installing the pot, I first drilled a small 1/8″ hole from the cavity side, so I’d know with certainty the pot would fit nicely. This helped know exactly where the full sized hole needed to be, but I’d have risked some wood blow-out, if I’d drilled the full-sized hole from the inside of the cavity. To prevent this, I flipped the bass over, so I was drilling in from the top side, and drilled my 3/8″ hole centered on the earlier hole. The 3/8″ hole was just large enough to allow what was almost a press-fit, for the pot’s shank. With the longer threaded shaft on this style pot, I can easily control how much of the shaft is projected above the top of the bass. To do this, I threaded a nut down onto the shaft, far enough so the adjustable portion of the pot is the correct height, and then with a washer and another nut on top, tighten it down so it is firm. This has a nut flanking the 1/4″ thick top, from top and bottom. If you have any trouble keeping this concept from loosening up, just bring a third nut into the mix. Place two nuts on the underneath side, tightened (jammed) against one another, and then handle the top nut in the same manner as i described above. This should stay put no matter what happens.

I was looking at some of the different plastic knobs I have on hand, to use on the volume pot, but none really looked appealing. Then it hit me. Why limit myself with plastic knobs? I chucked a blank of some nice colored Pecan, into my wood lathe, and I turned it to a pleasing shape. When I was satisfied, I sanded and added some oil finish, while it was still turning on the lathe.

Turned knob, still attached to blank in lathe. Red arrows point to the knob and to the parting point.

Turned knob, still attached to blank in lathe. Red arrows point to the knob and to the parting point.

Before cutting the knob loose, I put the whole blank into my vise, and drilled the hole to fit over the pot’s tip. I marked my drill bit with some of the blue painter’s tape, so I wouldn’t accidentally drill too deep and waste my efforts. After drilling, I cut the knob loose with a fine-toothed saw, and pared away some extra wood, which also added a little texture on the very top of the knob. Now it is just waiting for installation.

Knob finished and sitting next to a pot (not the one used), to show scale.

Knob finished and sitting next to a pot (not the one used), to show scale.

I hope to have a little time in the next few days, when I can drill and install the output jack, and complete the wiring. Then it’ll just be a few more little details to finish up all aspects of the bass. Until then….

Thanks as always for checking out my article. Please let me know if you have any questions or comments.


Lee Laird



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