A sliding pickup

There has been several attempts - by for example Westone and more recently Norton Guitars - to make a pickup that can be moved to the areas of the strings where different antinodes and their corresponding overtones are located. This gives you the sound of a neck pickup, a bridge pickup and everything in between. Though only one at a time.

The T-beam bass and the bracket for the humbucker pickup were too obvious a candidate to not trying something like this. And since I allow myself an impulsive and unstructured approach to my hobbies, I gave it a try.

The pickup bracket has nylon cable clips screwed to it. The clips grip the edge of the T-beam top flange and allows the whole thing to be slid easily along the beam. It was necessary to isolate the pickup from the vibrations of the guitar body (hence the rubber bands and foam padding). If not, the vibration characteristics of the string on the pickup's location would be hardly audible compared to the much stronger body vibrations also received by the pickup. Isolating the pickup also significantly reduced the noise of the nylon clips sliding along the T-beam... nice, because now it is possible to slide the pickup "in-tone" and hear the subtle changes of the timbre of the string.

The bracket and pickup is big and heavy, so one of the next steps will be making a sliding bracket for the much smaller between-strings pickup, which I made earlier. The small pickup should also be better at sensing a small section of the string, where the humbucker due to its length picks up a lot of vibrations - including the unwanted ones. With the big pickup, you can easily hear the difference up and down the strings, but the effect isn't exactly striking. I hope and believe that the small one will do a better job.

I had to rout a channel in the wooden sides for the nylon clips. With everything on, in the afternoon sun, it looks like this:

A vertical pickup

I made a pickup that sits vertically between the strings. Since the bass is two stringed, the pickup picks up one string from each side. It works well, but I have to keep it towards the bridge end, otherwise the strings will hit it.

It is made from an acrylic sewing machine bobbin wound (on a sewing machine) with a very thin copper wire: 0,05 mm which is somewhere in the neighbourhood of AWG44. This wire is thin as human hair and very prone to snapping... it happened more than once, but I've learned to handle the delicate wire.

I measured the DC resistance to 2,3 Kilo Ohm. I'm not sure how much I can deduct about its impedance from that information, but it's only around one fourth of the resistance of the humbucker that I used earlier.

The center of the bobbin contains a stack of small neodymium magnet discs and iron cylinders. This allows me to vary the magnetic force by replacing an iron disc with a magnet if I want it stronger - and vice versa, of course.

I can rest my hand on the pickup while playing, but sometimes it's in my way. Still, I usually find my way around it and I really like the simplicity of having one small coil picking up both strings. I might recess it a bit into the aluminium and I might abandon it in favour of a more traditional pickup, but overall, I'm quite satisfied.

BTW, I also made two tuning screws from ordinary screws fixed in oak dowels with epoxy glue. They have just adequate friction against the fingers, but they'll have to do until I get a couple of knurled nuts. Still, compared to using a screwdriver when tuning, it's a great improvement.

Using traditional tuners for headless designs

A post on this blog contains some nice sketches of headless guitars with traditional tuners mounted behind the bridge. Some designs even had holes through the body for the tuners. That looked good, but it might be difficult to get a good hold of the tuners unless the holes are very big. Since tuner systems for headless guitars are few and expensive, using the old-fashioned ones in new ways is a viable alternative.

It struck me that a possible solution could be to mount the tuners on a metal plate in a hole routed through the guitar, the tuner knobs sticking up through the plate and the strings going through slots in the plate. I've fiddled around with designs like that before (only on paper so far), but in this particular case, with a tune-o-matic bridge, it seems especially straightforward.

On one of the sketches on the blog, it would look like this. Sorry about the artistic quality, the picture only serves to explain the idea.

I couldn't attach images to my reply on that post, so instead i put it here. Anyway, it shouldn't all be about T-beam guitars.

A magnetic pickup

Previously, I've talked much about piezo pickups. I had great expectations to piezo discs, because they would give me more freedom in construction, since I would avoid having to make room for traditional magnetic pickups. I still have expectations, but so far, I've not been successful in making or buying a suitable pre-amplifier. I've tried a couple of designs, but none have sounded very good so far.


For the sake of my own motivation, I took a little detour from the piezos and put a guitar humbucker on top of the strings. The distance between the two rows of pole pieces is 18 mm - exactly the distance of my strings. This makes it possible to mount it lengthwise over the strings. It gives acceptable sound, but the mounting bracket doesn't integrate well with the overall design idea of having a sleek stick for a bass.

On the other hand, it _does_ have a certain rustic honesty about it. And most important: now I can play the bass and get a decent tone, while I figure out if the neck should be a little thinner, rounder or narrower. As well as many other things.

Wooden sides

I made two wooden sides from some spruce, just to test how it worked. Also to avoid messing up my good mahogany plank with early mistakes. I routed the cavities for saddles, nuts, strings and tuners with an ordinary plunge router in a table. I have little experience routing, but the cavities do what they're supposed to.

I've tried to make the sides fit tight against the top flange by having the holes in the vertical flange just a tad higher than those in the wood. This way, when I screw it together, the screw tightens the wood sides towards one another as well as lifting them against the top flange. It works ok... if you see gaps, it's because the wooden sides are made quick'n'dirtily, not because there's something wrong with the principle itself ;-)

I'll be sticking with the spruce sides for a while. There's a lot of things that I am yet going to try out - and which will need holes drilled in the wood. The mahogany sides will have to wait until I've settled on a final design. This especially includes whether to make the neck thinner. It feels a bit too thick even for my big hands, so I might slim it down from 4 to 3,5 cm (that's from 1.6 to 1.4 inches). That will still be much thicker than a traditional bass neck.

New tuners

I've always wanted to try out my a particular form of tuners for headless guitars and basses. They work by having a scew pulling a brass block in which the ball end of the string is mounted. The main inspiration was Jeff Turpin's tuners; drawings and building guide for similar tuners can be seen at ScottyD's home made tuners. But since I have a T-beam, I can do away with the housings for the brass blocks that these designs use, and rather let them slide on the underside of the T-beam like this:

Two of the screws are for holding the brass plate on to the T-beam
The other two are for tuning.


I thought that 'd give it a try since I was going to cut the T-beam to length and I needed a bit of room for the tuners, so it was the last opportunity to try it out. It works very well - very smooth and precise, so I'll stick with them rather than reverting to the traditional tuners. I believe they'll be even better when I've mounted hex socket screws so I won't have to use a screwdriver to tune them. The holes where the strings go through the top flange could use some lengthening as well, which would make the strings' movement easier.


The picture shows the sharp turn, which the cable has to do going through the flange.

I'll stick with the new tuners rather than the standard bass tuners it had on earlier. That will also make it easier to make some good looking wood sides for the T-beam since I won't have to worry about making room for tuners that stick out. The brass blocks and string ends will be hidden within the body.

Earlier, while the traditional tuners were still on the bass, I was making and mounting a string tree that I needed for them. Unfortunately, the aluminium is so soft and sticky, that I broke off one of my threading taps inside the T-beam. Trying to get it out by cutting room around it with a dremel only made things worse. I'm afraid that I'll have to stray from my "form follows function" principle and make some sort of ornament to cover the damage, now that I don't need the string tree any longer.

Headstock-end with damage from string tree mounting attempt
(I later turned the T-beam around so this end was the bridge end back then).

On the image above, btw, you can see the strings going through the flange. They are secured on the underside by cable stops - the type used e.g. for brakes on mopeds.

Next step will be making the wooden sides plus some experimentation with Piezo pickup pre-amplifiers. And then back to tidy up the T-beam. Later, I am thinking about making a detachable body from steam bent plywood.

Stick Bass Pictures

I've made the spine of the two-string, nylon string, fretless piezo alu T-beam stick bass. Now I have to stick some wood and some piezo pickups on it.

Some photos:

I will shorten bot ends of the T-beam down to the tuners and string holes. Btw, these are not nylon strings as originally described, but flatwound steel strings. I found out that the pull of nylon strings wasn't that much lighter than that of steel strings, so I went for these instead.

I've played it with a cheap non-preamplified piezo pickup on the flange. Sounded very good and feels very alive... I'll make some sound samples to go here. It even sounds good bowed. Plus it was easy to bow; since it only has two strings, they are easy to hit even though the fingerboard is flat (as in not being "radiused" like the fingerboard of e.g. a violin). So far, I am really, really satisfied with it.


Common bass tuners mounted in oak blocks. Bronze saddles through top flange. And yes, the saddles aren't completely perpendicular to the top flange. I'll mount them in slots in the top flange rather than in threaded holes, which will make it possible to adjust intonation. And then I won't have to worry about my crooked thread-cutting.

Action is ridiculously high at the moment, but if I set it lower, the strings don't press properly down on the saddles. I need a string tree, but I'll make it myself, since the strings are 18 mm apart.

Making the wood sides is next. Plus, I might trim down the "fretting" part of the neck to 25 mm (1") thickness. It feels too thick as it is now (4o mm). I was going to do that at some point anyway, but now I'll do it sooner rather than later.

The local staircase manufacturer kindly donated a nice piece of mahogany, and I've just bought a table-mounted circular saw. Plus, I am eager to use my router that I bought over a year ago and haven't used much. Making the wood sides should be a breeze.

Hope springs eternal.