Deaf Ray Overdrive

 After many software based distortion variations on Basscape I thought I would go more old-school. Most overdrive circuits are too gentle and most distortion circuits are too fierce in my very limited experience forcing me to make a decision as to which one do I want. Decisions were never my strong suit so I chanced upon an interesting schematic from an Orange Crush 15R. 

The overdrive in this schematic is shown at the top centre. By varying the drive control it doesn't just change the gain before a pair of clipping diodes that either shunt the signal to ground or use it as feedback, it blends between them. With the drive at max it is full-on hard shunt clipping, with the drive at minimum it is a barely perceptible feedback soft clipping with the ability to dial in anything in-between. Brilliant!

To give it a different feel to the original, the signal is passed through a 2-pole highpass filter that can be varied from around 200Hz to 650Hz. In addition to the frequency adjustment, the Q of the filter (the peakiness of the response) is controlled in tandem with the drive control described above. At low drives the filter is fairly relaxed  removing the low end that can otherwise dominate the overdrive tone. As the drive is increased, the filter Q rises and the tonal character can become more exciting and distinctive. 

The range of Q goes from about 0.7 (vanilla) to around 2.3 (mint choc chip). As with the high-pass frequency range this was mostly determined by trying it out until the the best range was found for the controls. The economical-on-battery-juice-and-my-pocket TL062 was used and all pots were chosen to be the same value so I only had to buy one lot. 

As I tend to play bass much more than a six-string I wanted a blend control more than an output level. The blend mixes the overdiven signal with a slightly filtered dry signal to still provide the bass guitar underpinnings even if theres a good helping of edginess going on. Which there usually is...

To avoid a complete rats nest of wires I mounted the pots on a separate piece of veroboard. The whole lot was fitted into a 1590BB diecast box and some artwork made to confuse onlookers. The Deaf Ray theme came about as I liked the idea of a laser on the front and in turn this caused the sensible controls like 'frequency' and 'drive' to be renamed to 'aim' and 'force'. The 'kill/stun' switch gives a more cutting sound with higher drive (kill) or a gentler warmer tone (stun).

The artwork was printed onto A4 coloured adhesive paper and lined up with the drilled holes before covering with a transparent adhesive film layer to protect it. Much better looking than my usual permanent marker pen scrawl. 

All the parts managed to squeeze into the box along with the two 1/4" jacks, dc supply, footswitch and controls. 

I was so pleased I made two...

Aim. Fire!

 

The Finishing Touches

 Bouncing along

After a successful wind-up, the completed spring was slid onto the main tube. A 90 degree bend made at the bridge end allowed the coil to be anchored by passing the wire through the last fret position hole (drilled earlier for guidance). Each coil was nudged into position before fastening at the head end using a bicycle brake cable clamp-bolt. Finally the entire spring was glued to the tube with epoxy resin to prevent it wandering about. This was a bit messy and a fair bit of IPA was used in cleaning off the excess before it set.

Tuners

Conventional closed gear tuners were used. These are normally fitted into the headstock which is around 15mm thick. The stainless tube is only 1.5mm thick and is curved! To get around this (quite literally) four circular aluminium spacers with OD = 30mm, ID = 16mm and length 24mm were sawn into 16mm & 8mm lengths then shaped to fit either side of the tube wall. 

It took a fair bit of whittling to match the tube shape. The tuners were then fitted to the tube using these spacers to sandwich it all together. The smaller convex spacer is on the inside. The small wood screw that normally prevents the tuners turning under tension is replaced with an M2 bolt that also passes through the main tube wall and clamps both parts of the shaped spacer.

Bridge

The separate parts of the bridge were assembled into fixed and adjustable sub-assemblies. The fixed part is bolted to the body tube and the adjustable part is clamped to this using M6 x 75mm bolts. This allows +/-4mm of height adjustment and a certain amount of sideways wiggle too. Angled holes were drilled into the taller end part of the bridge for the strings to pass through before sanding and polishing. 

The string grooves were cut into the saddle, and a horizontal groove cut underneath to allow space for the piezo pickup (see below). A drawback of this single saddle style of bridge is the limited intonation adjustment. I'm over it already...

Pickup

As this guitar is based on a tube, the strings cannot 'fan-out' from the nut to a larger bridge spacing without causing the action to increase significantly too. The spacing at the bridge is kept to be nominally the same as at the nut to prevent this increase in the action height and therefore requires a very small pickup too.

The smallest pickup I could find was for a Ukulele. Even this was too long so it had to be dismantled. The individual piezo elements measured around 7.5 x 1.2 x 1.2mm. 

The first attempt sounded wrong using 3 elements. The middle element must have been too high causing The E-string end to be very weak. The centre element was removed second time around and with just two elements it sounded peachy! 

Altogether Now 

I'm very pleased with the spiral frets - they are no more difficult to play than straight ones. I deliberated over shimming the zero fret to make it slightly taller but actually got round to it. A truss rod was not required as the neck is an inherently stronger shape and shrugs off the string tension without showing any signs of curvature at all. A properly set up bass neck does actually have a slight bow to accommodate the string as it vibrates back and forth. This cannot be achieved here.

I've never used piezo pickups before and the sound covers the full audio range regardless of cable length. A common-place wound inductive pickup will have an electrical resonance that can be worsened by excessive cable capacitance. This can be caused by a long or a cheap cable. Above this resonant peak, which can itself add a bit of sparkle in the right place, the output drops noticeably reducing the amplitude of higher frequencies. The piezo pickup is in essence a capacitive pickup and additional cable capacitance makes very little difference. 

The tonal character of a stainless steel tubular body, new strings and a piezo pickup system result in an extremely bright sound. This can be tempered by adjusting the playing position of the right hand to give a fuller sound. The same trick can be done on a conventional guitar but due to typical body shapes only a small range of playing positions seem feasible. On the tubular bass, there is no body or other points of reference, so the right hand can carry on up the fret board giving almost hollow synth-like tones.

Other than that, to be honest, it's a complete nightmare to play 😮 The string spacing is very tight for the right hand, and the picking hand has to reach round under the tube for the higher strings. 

Ergonomics were not that high on the list of important considerations.

It has stretched the concept of guitar construction in a new direction, but also reinforced that conventional guitars are good examples of incremental development. That being said, with a D-shaped tube and some welding, a more familiar neck and body could be crafted giving rise to an instrument that would have more universal appeal. 

But I like the prototype - it still looks like an exhaust pipe from a Lamborghini Murcielago 😊

The Steelworks

 An unexpected problem of this bass build was the complete lack of any useful edges or datum lines. Before any holes are drilled or cutouts are made, the tube needs to be marked out. This can't be done freehand, or with a ruler so I had to think outside the, um, tube. Fortunately a bit of spreadsheet magic enabled me to plot some graphs that I could wrap around the tube and use as cutting guides. Once in place it was time to fire up the angle grinder - not a tool I normally use when making guitars!

The guide allowed the two cutouts for the headstock to be made and marked the tuner holes for drilling too. 

Making holes in stainless with ordinary HSS drills is often less than successful, cobalt ones seem to fare much better. 

Fretwire?

Bashing fret wire into wood is quite satisfying. Bashing them into perspex as I have done on the last two builds is not great - it doesn't have the same give and one bash too hard could end up cracking the whole fboard. For the perspex fboards I had to make wider slots then rely on glue doing the rest. There has been one or two dislodged moments over the years, but on the whole they have lasted well. Cutting accurate slots on the stainless tube could have been an option, but I think it would look 'bitty'. Besides I had another daft idea that could only work on a tube...

Curly Wurly

Wouldn't it be great to use a specially wound spring fitted snugly on the tube to act as frets. It would start off with a wide coil spacing and reduces each turn. Between frets 12 and 13, the coil distance would be half that between coil 0 (the nut?) and 1. I drafted out a spec, supplied the equations and sent it off to a couple of spring companies for a quote. 

The coil winding fboard approach had a couple of side effects:

1. the frets won't be conventionally straight (perpendicular to the neck), they will be angled

Dingwall guitars make basses with fan frets. I've never played one, but apparently they combine good tone with playability. As long as the frets under each string are accurate to a single scale length, it doesn't matter that an adjacent string has a different scale length. Using a coil spring for the frets should be exactly the same. To capitalise on the thicker-strings-needing-a-longer-scale concept, so I'll need to ensure the spring is wound in the right direction!

2. the frets will also be on the back of the neck

Mmm, I suppose they will, but I'm going to do it anyway

Meanwhile, the spring company replies came back. One wanted £250 + VAT just to develop a spring with no guarantees of success, the other just wished me good luck...

The sensible option here would be to make the design more conventional, cut nice perpendicular slots and glue individual pre-radiused frets in. So I decided to make a purpose built spring winder instead*. Boing said Zebedee!

*To be honest I did try winding a spring manually first just to see how difficult it was. Stainless steel likes to fight back so this prompted the spring winder to be pretty chunky. As can be seen from the pic, manually winding a spring results in a very irregular string spacing which is no use at all.

Useful info gleaned from this exercise was the diameter of the former on which the spring is wound. Empirical equations exist, but this application is a way outside the normal wire-diameter-to-spring-diameter ratio. Two or three trial attempts showed that with a former of 30mm, a finished spring ID of approx 49mm was produced which was ideal.

Tubular Bass

Making a bass out of a length of exhaust pipe is tricky to imagine in detail. The compromise between fboard radius and a tube that I could hold and potentially reach the strings was a bit of inspired guesswork. I eventually settled on a 1.2m length of 50mm diameter stainless steel pipe to be the basis of this creation. It has a 1.5mm wall thickness and weighs around 4kg. 

To get an idea of how it would perform under stress (probably much better than I do 😮), a piece of 25mm x 50mm (1mm thick) 1m steel box section was tried. A couple of strings were fastened to it and it was tuned up. Under tension, the box section did not bend or warp any measurable amount, so the stainless tube is expected to shrug off the string tension easily without even breaking a sweat. 

Incorporating the tuners was the next hurdle. The tuners have to be fitted on the outside of the tube so they can be adjusted. That implies that the strings will need to be inside at that point to wrap around the peg part of the tuners. A cutout will be required for the strings to pass through, with enough finger space to allow strings to be changed. Fellow band-mates will tell you that I only change strings once every 20 years, but they exaggerate. It's probably more like 17 or 18...

Creating an opening for the strings that can be made with an angle grinder is one thing, but working out how everything will fit was seriously testing my sketching and trigonometry skills. It was time to go down the 3D CAD route just to try and visualise the thing as a whole. After a bit of mouse-clicking I chose a package called FreeCAD which uses the make-a-2D-shape-and-extrude-it concept (amongst others). After running through a tutorial I was ready to do some virtual work.

The headstock cutout developed into two matched cutouts allowing string access from above and below. The large holes are where the tuners will be fitted. I'm not modelling the tuners in 3D CAD! The tuners will need some sort of flat-curved washer system so that they can be clamped either side of the tube. 

A round aluminium disc will be mounted inside the tube by the tuner cutout. Another offset disc functioning as an adjustable nut is fastened to this and will stick out of the cutout by a few mm to support the strings. 

I then turned my attention to some dodgy 3D bridge scribbles I made earlier.  

The bridge also requires a cutout and inspiration came from the whistles in Steamboat Willie. The strings are not wrapped around anything at the bridge end, so it can be a smaller opening.

The bridge is also based on a set of aluminium discs. The bridge takes more string load than the nut so two static discs, followed by three other offset, er, shapes to create anchor points and a saddle area. 

What about the pickups?

The cutouts are mostly filled with aluminium and are physically positioned at the ends of the strings. Introducing a third cutout to house a pickup was considered, but would introduce an unnecessary weak point in the middle of the tube as well as making it look too conventional! Having a set of split P-bass pickups sitting in the middle of the tubular bass would give its purpose away too quickly.

A small piezo pickup designed to go under an acoustic saddle is going to be used to convert strings into signals. The piezo device is around 50mm x 1mm x 3mm and is unlikely to add anything significant to the weight of the instrument 😉.

Well, that's the theory. It remains to be seen how much of this is successful...

Jellybean Bass - Completed

The devil is in the detail

Back in April, I managed to get the five LED outputs sufficiently interleaved so that there would not be any noticeable delay between them. With the rest of the guitar mostly together, the bulk of the work left to do is now software based - ie getting the LEDs to do something fancy looking. 

I'm not really a software person, but can see the benefit of building functionality up in stages. At the lowest level I need a function that can take LED data from an array and send it to the LEDs when it is called. Above that I need functions that fill these LED data arrays with a colour value, scroll them in a given direction or place characters in them. Above that comes the fun part of putting the building blocks together in order to achieve some blobs floating around or pacman chomping through the maze.


A few pointers

I struggle to understand pointers in C. I'm sure I've used them for years, but they never fail to trip me up. Unusually, MPLAB C requires some pointer operations to be in brackets to add to my confusion.

*ptr = 27;

would normally work, but for MPLAB C, it has to be 

*(ptr) = 27;

It's fine once you know, but caused me a lot of headscratching at the start. Incrementing pointers doesn't require brackets, but when referring to the item being pointed to, it does. 


Being sympathetic

When taking LED data and writing it to the five streams of LEDs, I did not want excessive array decoding to slow the process down in case it started blurring, smearing, flickering or becoming intermittent. I decided to keep the LED data array straightfoward at the expense of wasting a little storage space. The WS2812B devices need 24 bits each (8 red, 8 green & 8 blue), but the integer variables available are 8, 16 or 32 bits. Using 24 bits per LED struck me as a bad move as it did not correspond to a standard integer of any size, and it also did not leave me any contingency space in case I discovered something vital later...

I found some info about bitfields, so I used a memory-friendly structure that fits 32 bits, with an enable bit and seven spaces for anything that might turn up along the way. The normal RGB order was swapped for BRG so that the bits could be sent to the LEDs without any reshuffling.

struct LED_DATA_STRUCT_32
{
    int   blue   :8;
    int   red    :8;
    int   green  :8;
    int          :7; // spare
    int   enable :1;
};

Another early thought that has worked well was to have foreground and background LED arrays. These are combined before passing the result to the LED update function. This layering can give a mild impression of depth or at least keep things separate when the going gets tricky. 

The visual side of the software has evolved into three sections: displaying text, animated effects and transitions. The text display was conceived first alongside the first transition - scrolling left. Now there are around twenty animated effects, ten transitions and over sixty text phrases that get trotted out. The sequence of operation now is:

text - transition - animated effect - transition - (repeat)

There are also some hidden test modes that check the LEDs, plot various ADC values and a screen saver mode that looks like tiny bubbles rising to the surface!


I've got the power

During the software development phase I often had static LED patterns. Sometimes these would be on for half an hour whilst I tried to get the ideas in my head translated into code. During this time the neck temperature would rise by approx 25 to 30 degrees Celsius and is enough to change the neck relief! 

The truss rod adjustment was carried out when the neck was at room temperature, but the compensation was too much when hot leading to a large amount of fret buzz. My working theory is that the acrylic f-board provides a certain level of additional neck stiffness, but as the temperature rises, its contribution reduces. 

To combat this effect as much as possible, the neck compensation was reduced to an acceptable minimum, but the majority of the improvement in neck stability is from LED power reduction. All the effects were adapted to use 1/2 or 1/4 power where possible, especially when more than half the LEDs are on. Fortunately the LEDs are very bright on full beans even through smoked perspex, so this also helps cut down the glare and allow standard phone cameras to take pictures without completely saturating.


Effects

Once the bluetooth link has been established the mode changes to auto so that all effects can be called up. Other modes can be set manually, again using the bluetooth comms link. 

The effects are numbered in pretty much the order they were written in and are described below.


1 - user text (entered by bluetooth link)
2 - preloaded text

Both text effects are run from the same function, the only difference being the source of the text phrase. During this stage the bluetooth comms link and message passing protocol had to be constructed as well as scrolling left and right and even defining a variable width character set. A hue function was also written to take a colour wheel value and convert to red, green and blue LED values.


3 - fret dots

Fret markers are quite a normal feature on most guitars. Some are just dots, some are more impressive blocks, ramps or crosses. The LEDs are fixed to the PCBs, but with a good choice of grid (some time ago!) and careful placement, the majority of fret marked positions line up fairly well. Once these had been identified, a variety of fret marker shapes and cycling colours are possible. 


4 - balls

Bouncing balls uses floating point variables so that the balls glide effortlessly instead of stepping from one LED to the next. Slightly reminiscent of a lava lamp, but warms up quicker!


5 - comets

Comets was an accident. It uses the same function as balls, but was supposed to only give the outer perimeter. It didn't look too bright to start with, so the deleting at its old position was removed and replaced by a gradual fade out. This allowed the circular outline to create a pleasing trail. 


6 - zig-zag

I wanted to do a scramble / defender style effect, but was still finding my way. I made a basic zig-zag terrain for an imaginary spaceship to fly through. The separate foreground / background layers were used with one zig-zag on each. They are colour cycled, scrolled and faded separately which creates a nice psychodelic feel. Hip & groovy man!


7 - pacman


The original moonbassalpha had a pacman theme. This was around 10 years ago and was my first bass build. It's still going strong :-)

With 80 LEDs across and 5 LEDs high, the 'screen' is not really the right shape for a pacman maze. On the other hand it is quite wasteful driving a whole screen when the pacman is the only bit that is important!

How many idiots does it take to paint a fence?
100! 
1 to hold the brush still, and 99 to move the fence up and down.

We've all heard this joke before, but this was a lightbulb moment for me. 'PM' is fixed at the centre and the maze moves around. PM, the ghosts and all maze features are based on 5x5 LED characters. 

To ensure that (human) eyes can track the maze movement, everything is moved one dot (height / width) at a time, in other words it takes five moves for the player to move one character sized space. This gave some tricky arithmetic when calculating relative positions of all the main players to see if PM and any of the ghosts meet.

Pacman sometimes shows the score, and sometimes doesn't. The effect looks better without the score, but with the numbers, the gameplay can be appreciated more. The game continues until PM bumps into a ghost.


8 - space journey

Space journey uses single point perspective to simulate a flight through, err, round multicoloured asteroids. Looks better from a distance, but in space that shouldn't be a problem ;-)


9 - kaleidoscope

Nice, simple and effective. Random chevrons are produced in the middle, and scrolled out to the edges. It reminds me of the shapes produced by a kaleidoscope that I had as a child.


10 - string bean 

This obscure name is really just good old fashioned 1970's sound-to-light. A feed from the pickups creates an envelope signal which is connected to an ADC input. When the strings are played, the filtered output is converted into size / colour pulses which are scrolled across the fboard. 


11 - tetris

This was another brain bender. Making blocky shapes and scrolling is ok, but working out the profile of where they might land and the best way to rotate them is not as easy as I hoped. Filling up the screen up takes a couple of minutes, so this runs for a bit, stores the info and then next time it picks up where it left off. 


12 - running man

I must have watched a cartoon when I did this! The idea is that a man walks left to right and then gets chased back by something. Currently the chaser can be other men, a pacman, a ghost, a car, a spider or a snowball increasing in size. The spider needed to move in a particularly menacing way (in my mind).

13 - barrels

I thought about the donkey kong game, but this was as far as I got. A barrel rolls down red and blue inclined planks. No gorilla though.


14 - cells

The idea of growing cells continually splitting themselves in two was the basis for this one. I did not realise, but this is known as binary fission.

The single cell splits into 2, 4, 8 and eventually 16 parts (as these all divide nicely into 80 LEDs and 32 does not). 


15 - aztec

I like the idea of weird heiroglyphic symbols put together like a sort of secret message. These symbols rotate up and down and colour cycle to make sure that nobody can crack the code. Well, I can't anyway...


16 - fruit machiine

Three wheels, each with eight different fruits on them. The wheels are triggered from different positions, run at different speeds with different friction coefficients to keep it interesting. Occasionally all three match, but there is no coin tray for the winnings yet, so I've got to be content with a moral victory only.

17 - driver

Another dabble with perspective. I used some online help for this one.
It really needs a taller screen to look more effective, but it gives drunk people something to puzzle over.


18 - scramble / defender

After the first zigzag effect, I tried again. This time it went swimmingly well. Like pacman, the main space fighter ship is more-or-less central and the terrain moves up and down whilst scrolling past. The space fighter has a laser cannon and can blast holes in the landscape! 


19 - diamonds are forever

A coloured-growing-shape-with-fade sort of pattern. Allows spectators to chill out after some of the more intense effects.


20 - streetlife

The thought here was a frogger style game - trying to cross the road without getting squashed. Again, due to the screen proportions, there wasn't any room for pavements so it is just a plan view of a dual carriageway. A bit of nous had to be used to allow vehicles to move from the slow lane to the fast lane and vice-versa without just crashing. They have to use their virtual mirrors in order to overtake and speed up! I am sure I have seen tail-gating and cutting-up too, I should have called it roadrage!


21 - fret dot halo

The fret dot effect is good, but quite static. To spice it up slightly this allows each fret dot to expand and contract at its own rate.


22 - centipede

The centipede game also needs a proper shaped screen. It wasn't going to get one, so I decided to split the game view into three sections - top, middle and bottom. The centipede worms its way from top to bottom, avoiding mushrooms. The shooter at the bottom fires indiscriminately at the centipede and the mushrooms and eventually it is all shot away. Sums up life in many ways...


23 - random squares

Does what it says on the tin. Difficult to add much more here.


24 - digger

I was determined to use the pacman 'engine' for something else. This chap is living underground, digging for diamonds and trying to avoid falling rocks. 


test modes - just for me

90 - signal envelope
91 - random noise
94 - prbs15 (15 bit PRBS x^15 + x^14 + 1)
95 - prbs9   (  9 bit PRBS  x^9 +  x^5 + 1)
97 - blank
98 - idle (when on stand)
99 - led test mode

A transistor base-emitter junction is configured in reverse breakdown and the resulting noise amplified up. This is sampled by ADC1 and is a true random generator. Unfortunately it is updated quite slowly in comparison to some functions that require hundreds of random values in an instant. To help with this, a PRBS (Pseudo Random Binary Sequence) is also used to derive seemingly random numbers. When the proper random number is sampled, it is used to reseed the PRBS generator to increase its entropy. 

But more importantly it makes dots jump around when viewed as a test signal!

Idle mode is entered automatically when the tilt switch detects that the bass is on a stand. It uses lop-sided filtering to ensure that entering idle mode takes several seconds whereas leaving it is much quicker. This avoids the effect disappearing when I hold the bass vertically (at the end of a rowdy number), yet kicks into life soon as it is picked up.

The LED test mode has already showed one LED has a problem with green, but other than that all is well. I will get round to replacing it one day...

List of transitions:

fade, sparkle dots, blank dots, sweep, scroll left, scroll right, scroll up, scroll down, monochrome fade, blur fade



All done and dusted

So far the Jellybean Bass has done 4 or 5 gigs and hasn't missed a beat. Hot plugging and unplugging does not cause any audible noises and now the neck heating is reduced, it does not change significantly during use. 

I still have plenty of code space that could be used for more effects, but will need more inspiration for further eye candy.

95% of people are just happy to be watching a band in a pub with beer in their hand and do not notice anything unusual, but the other 5% watch in total disbelief. Guitars cannot do that...can they?

It must be a sign

It was a dark and wet day at Guildford train station. Platform 5 is one of the few places in the world to be more than 10 metres from a Costabucks. On the one hand I could run up & down the stairs, join the queue, decide exactly which type of (basically all the same) beverage I wanted before returning with my prize, or I could just sit there and make do with a faint aroma wafting across from Platform 1. If the train were to arrive and depart whilst I am on this quest then it won't be just the milk that will be frothing.

To aid my naturally poor decision making ability, I glance up at an information display to see how much time I have to play with. I notice the sign full of LEDs displaying the next train and the stations it will stop at.

I start to count how many dots in the characters and wonder how they are multiplexed. I think about how much processing is done behind the twinkly lights and if it uses as much energy in one hour as a kettle boiling one cup of water to make instant coffee at home. I decide that Costabucks will probably survive without my patronage and before I know it, the train arrives.

Later that day I actually get round to practising a song (for one band or the other!) and I look at my dark fretboard and think wouldn't it be great if it had lots of LEDs on it. I've never seen a bass guitar with an LED sign on the fretboard. There really isn't enough room for it and it's a silly idea. Unfortunately I'm the sort of person that believes these are exactly the right reasons for building one anyway.

I have a reel of 800 RGB LEDs sitting in the cupboard (Everlight SAGBB7C). These use the standard 5050 SMD package with 6 pins. Each led will require its own driver channel and for any decent sized display that's a lot of complex-stuff-to-go-wrong to be installing inside a bass neck. 

The WS2812B LEDs used on my 'damp' project would be ideal. The same 5mm square SMD package, but this time only 4 pins. Power, ground, data in and data out. They use a clock-less serial data stream based on high and low mark space ratios giving 1's and 0's. The main bonus here is that apart from the LEDs themselves, there doesn't need to be much else in the neck - ie less-to-go-wrong-where-I-can't-fix-it. The downside is that these are NOT sitting in a cupboard, so it's more on the shopping list.

I want this bass to look reasonably normal when its off, so I'm going to purchase a jazz bass style body and neck online and pop a few RGB LEDs in along with the control circuitry. With multi-coloured action going on, this Jazz Bass has ended up with the name Jelly Bean before it has even begun. 

With confirmation of my mental age out of the way, it's time to work out how it is all going to hang together. Some prototyping is going to be needed up front before I spend serious money on the body as I need to prove that a (simple to solder) Microchip PIC will be able to control separate daisy chains of LEDs in parallel. There are many other devices out there which may be more suitable but I already have a PICkit3 programmer, so it's PIC or bust. 

Stripping In The Blue Light District

The Ibanez body is quite a dark brown color. I thought it was a solid paint finish for many years, but if you take a fresh look there is definitely a decent bit of woodgrain going on underneath a heavy lacquer.

The bass is a lawsuit model dating from the mid-seventies and has had some remedial work carried out already. The original Gibson three-post style bridge was replaced (quite rightly) and a thumbrest was ditched. The holes left were filled with wooden plugs and under the dark lacquer the repair work was practically invisible. The bizarre shaped cutout that looks ideal for storing ice-lollies was hidden away under a scratchplate.







Half way through the paint stripping and Chewie & me are wondering if perhaps we have been a little bit hasty. It is looking quite rough now. Talking about different new paint finishes keeps us going...



Once the paint stripper has done its chemical nastiness, we attacked the surface with sandpaper. It was like trying to sand glass. At this stage other uses for the body were found, such as the latest in guitar-inspired lingerie...






It took power tools and some good old fashioned grunt to shift whatever was still clinging to the wood, but evetually the mist started to clear. The paintjob had been hiding quite a nice veneer. The body could now be seen properly and was constructed from five layers of differing thickness hardwood (plus two [ash?] veneers), with the grain direction changed on alternate layers. With the contouring on the body these layers show up as go-faster-stripes. When the hardware gets bolted back on, this is really going to look smart.

Back in the land of fboard lights, the plastic dots have been shaped using 6mm and 8mm formers. The dots have been glued into the board and here are the results:

Funny how turning the lights on makes the wood get darker...

Moon Bass Alpha - Planning The Mission

Moon Bass Alpha - I know its a silly name, and I'm unlikely to play bass on the moon, but I could have spent months thinking of something else instead of actually getting down to the, er, wood and two nails. Some people have heard my playing and think that the moon is probably not such a bad idea.

Sticking My Neck Out

I believe that the neck wood must contribute more to the overall sound than the body wood, as the neck is flimsy and will vibrate and bend when a note is played, whereas the body will barely move at all. The neck also covers more than half the scale length so I think that choosing the wood for the neck will dictate how the 'wood' part of it sounds.

Most guitars I have seen seem to have maple necks. My own guitars have maple necks, or at least maple and something. Having said that, I am pretty sure my Peavey Cirrus BXP is made from Obeche. It is as light as a feather (in comparison to the Vigier). But anyway, I wanted something to sound different so I have made my first bad decision and ruled that maple is not going to be used on Moon Bass Alpha.

Great! Out goes maple, in comes, um, balsa?

Paper. Books and libraries and t'internet. I have invested in "Make Your Own Electric Guitar" by Melvyn Hiscock and it seems very helpful. Other books on 'What has wood ever done for me' etc have been dribbled on in the pusuit of knowledge. I noticed that some guitars (particularly Warwick) have used Wenge necks in the past. The local timber merchant seemed to think it was the sort of wood you would use in a dockyard, but it appealed for a number of reasons: 1 - it isn't maple; 2 - it is a very dark brown colour unlike maple; and 3 - it has a coarse grain structure which ought to help create a fuller, more mellow tone and growl.

Unfortunately I like laminated necks. The stripey-through-the-body look does it for me. I need another wood type for the neck. After contacting craft-supplies.co.uk (who do wenge laminates) the choice narrowed down to Bubinga and Padauk. I have gone for the Padauk because: 1 - Padauk is a really nice red colour; 2 - It is reasonably good to work with; and 3 - I am not quite sure how to say Bubinga without it sounding stupid.

A few layers of contrasting white oak veneer from valeveneers.co.uk (keeping to the no maple rule) and the neck layer build up is as follows:

WOPWOPOWPOW

It reminds me of watching Batman on a Saturday morning, but what it meant was W = Wenge (1/2"), O = Oak (0.6mm) and P = Padauk (1/4", except centre which is 1")

Here's the wood as it turned up. W x4, P x3 and an ebony fingerboard. Ebony is about as non-maple as you can get! Don't get me wrong about maple - I like the syrup, but I just want something a bit different in the neck department.