Setting up a fretless bass is supposedly very similar to setting up a fretted bass. The main difference in the geometry is at the nut, where the strings sit just a fraction of an inch above the fingerboard – (since there are no frets to clear further down the neck). I’ve already fairly well covered setting up a fretted Jazz Bass here, and the process isn’t that different from setting up a six stringed guitar. Here – I will follow the same sequence of basic steps, with a few additional notes specific to the fretless geometry.
But a bit of easy housekeeping stuff first… a few more bits of hardware to attach. A set of black Fender strap blocks for the strap buttons. (I really am testing myself this morning…). Then – a chrome bridge cover “ashtray” (Fender parts number: 001-0108-000). The metal cover is positioned and centred over the bridge plate, and the two mounting holes traced through onto the body with a sharp awl. After drilling out the holes to suit the mounting screws, (2 x Fender parts number 002-1422-049), and slightly countersinking them to clean up the edges – the cover is screwed down into position.
Then – removing the scratchplate, and measuring the correct locations centred on the pickup openings – two mounting holes for a chrome, Precision type cover, (Fender parts number: 001-0116-070), are drilled through the plate from the front – using a sharp HSS bit and a wooden backing block, to prevent the holes from “tearing out” on the reverse. With the scratch plate replaced – the holes in the plate act as markers, and the screw holes can be drilled out into the body beneath, to accept the attachment screws. (Again – 2 x Fender parts number 002-1422-049). After tapping the new holes, and checking the Precision cover for fit – I leave it off for now… The working height of the pickup still needs to be assessed, and correctly set.
A Fender “Tug Bar” (Fender parts number: 099-2036-000) is supplied with a paper template, to assist positioning above the strings, (in the “modern” style). The same bar fits Precision and Jazz basses – but on the Precision – one of the attachment screw holes coincides with one of the scratchplate mounting screws. This screw hole needs to be slightly enlarged in the scratchplate, (using a sharp wood bit to cut the edges equally, all around). This can then be used to mark and drill out a new hole in the body, for one of the tug bar attachment screws. Once the tugbar has been set in place with this screw – the tug bar itself can be used to mark the location of the second screw, (according to the template) – and this hole, in turn, is marked and drilled out. Finally – the tug bar is secured in position with the second supplied screw.
One last addition… a chrome, disc-type string guide, (Gotoh – RB-20 type), is fitted to the headstock. The previous string tree has apparently been placed wrongly by the previous owner, and isn’t exactly in-between the two strings as it should be. I drill a brand new hole, and fit the new string guide so that the disc conveniently covers the old hole from view. The hole itself can be simply filled with a coloured furniture wax, to approximately match the amber headstock.
On to the setup. As I say – a fretless bass is supposedly set up the same as a fretted bass – although I’m sure there are likely to be a few specific issues at the nut. However – in theory – the playing action should be roughly the same. The procedure followed, will be much the same as with a regular, fretted bass. First – to measure the natural curve of the neck under the full tension of the strings the bass is brought to tune, capoed at the first fret and – with a finger fretting the top “E” string at the highest fret – the distance between the bottom of the string and the fret board is measured halfway between – at the eighth fret. (Note: Since there are no frets – when you “play” a particular fret – you need to land on the marker, instead of just behind it, as you would on a fretted instrument. If you’re working with a fretless without markers – there may naturally be a little bit more “approximation” or “slack”, in your setup).
Measuring the gap – a 0.015″ feeler gauge still has a bit of freedom below the string – so I need to dial in a little back-bow, by turning the truss rod adjuster clockwise. Access is at the headstock end here – so… small adjustments at a time… eventually I get to the desired 0.010″ clearance with approximately half a turn in total. The recommended target clearance comes from the usual Fender specifications and recommendations – but they only seem to cover up to 17″ radius fingerboards. This particular board seems to measure out at somewhere around 19″ / 21″ – but I’ll set it at 0.010″ (as if for a 17″), and see where we go. (It’s possible that the fingerboard has been prepared with some potential for further refinishing in mind. As I’ve researched fretless basses a little more – I see there’s a tendency for some players to prep the board with a hard, shiny lacquer. Some even recommend sealing the board under layers of hardened cyanoacrylate! I’m not quite sure what this board is made from – but I’ve only ever used a borrowed fretless with a normal rosewood board before and, since that’s what I’m “used to” – that’s what I’ll stick with).
On to the nut… The pre-installed nut has already been slotted, and it’s immediately obvious that – with a fretless – the plane of the fretboard appears to be higher, in relation to the strings. (Almost as if the gaps between the frets have been filled in level). Practically – that means that there’s virtually no “height” to any of the string slots at the nut – and the strings, therefore, sit right down – almost on the fretboard. Practically speaking – there just needs to be enough to prevent the strings vibrating against the wood, behind the fretting finger. On my fretted Jazz bass – I eventually got a nice low action at the nut, with the clearance over the first fret to be in the region of 0.006″. (Remember – it’s not only the action that benefits with correct adjustment at the nut. String intonation too can be out, if the nut isn’t adjusted properly). Setting up the neck with the capo at the third fret – as shown above – I can check the clearance at the first fret, under conditions with the second fret both fretted, and unfretted. There’s clearly still a small amount of tolerance to play with – so I think I can take just a few shavings more from the bottom of the string slot…
This is done by detuning the string – pulling it off to one side, and carefully filing the slot down with a gauged slot file, (this one is 0.105″). The file is angled down towards the line of where the string wraps around the capstan, at the bottom of the tuning mechanism – in order to provide a sloping groove, with the highest point at the playing edge of the nut. In this particular case – it’s unavoidable – but I also take enough off to create a bit of a groove in the sloping top of the fretboard, on the side closer to the tuning pegs. This is OK behind the nut – but you have to be really careful that you don’t ever touch the string side of the fretboard with the file.
After a few passes – the slot is cleaned out with some ultra-fine grit paper, and the string is returned to the slot. After retuning – the string clearance at the first fret is checked again, as before – and the process repeated, as necessary until the tensioned string is at the desired height. Once the top “E” is sorted – the rest of the strings are attended to, in a similar way. In the close-up photo above – note how the strings remain a fraction above the fingerboard at the playing side, and how they slightly cut into it, on the headstock side.
Now – tuning up and playing the bass – I can see that I’ll now need to drop the string heights at the bridge slightly, to create the ideal playing action all the way up the neck. However – I’m already getting that certain “trumpety” flare to some of the notes – especially higher up the neck. You know… that particular fretless “warble“. On a guitar – that would usually be a bad thing – so there’s a natural inclination to try and completely eliminate all string buzz. However – on a fretless bass – sliding into the notes and having that slight “flare” to the notes… it’s all part of the character. Instead of eliminating – I think I need to learn how to control the… what to call it??
Ah! – a bit of online research… It turns out the particular quality I’m trying, (and failing), to find a word for, is technically referred to as… “mwahh“…
I’m reassured that “mwahh” is a natural feature of a correctly setup fretless bass, and that a fretless setup is no different – in terms of playing action – to that of a fretted bass. So – checking the string heights, and playing action, at the 17th fret as usual… the low “E” is measured as being 0.3 or 0.4 millimetres too high from where Fender says it should be…
But – if I lower the string, surely it will buzz more?..
I’m reminded that setting-up any guitar, (or bass), is usually about finding a correct balance for string tensions / heights, and their geometry over the bridge and nut contact points. Until the bass is completely setup, including the intonation – perhaps all things pertaining to the generation of “mwahh” remain variable?… Everything I read certainly seems to stand by “the usual” setup adjustments and tolerances. I decide to push on regardless of how I’m perceiving any “string buzz” (or should I call it “auto“-mwahh??) – and continue adjusting according to “Fender standard specifications“. For basses – that’s outers string heights of 2.4mm on the bass side, and 2.0 on the treble…
Height adjustments are made by raising or lowering the strings at the bridge saddles – adjusting the pair of grub screws for each, until the string passes above the line of the 17th fret at the desired height. (Keep the saddle “barrels” level – to keep the strings as stable as possible at the contact points). After each adjustment – the bass is retuned. Once both outside strings are at the desired height – the two remaining strings are adjusted “in-between” – so that the plane of the strings somewhat follows the curve/slope of the fingerboard. In practice – and since the strings on a bass are a little further apart – I find I can use the same “step gauge” string height tool, to set the height more exactly.
Once the string heights have been adjusted according to specification – I turn to the intonation. The saddles on this (pre-used) bridge are all too far forward… The, (12th fret), octave notes for each string are sharp, compared with the open notes. All four saddles will need to move back… This is achived by turning each adjuster screw clockwise, at the back of the bridge. Tunings are checked again with a chromatic tuner – and the bass is re-tuned after each and every adjustment. This ensures that the neck remains in the exact, correct bow for the tuned, working string tension. Since, also, the mass of each bass string is considerably larger than it’s guitar equivalent – it’s especially recommended to check the tunings and intonation, each time, in a playing position – with the body of the bass held vertical. Even gravity has it’s part to play in the vibration of each string, and the overall “balance” of the system.
With all string adjustments set to “Fender vanilla” – I’m still getting a certain amount of “mwahh” – although, perhaps, not quite as much as I was getting before. It’s hard to tell, and I’m not sure if something’s going on, which is all a bit counter-intuitive. Certainly – the playing action now feels nice and easy – and there’s a natural tendency, (especially with the flatwound strings fitted), for me to slide into position for notes, (perhaps accentuated by having to get used to the slight playing difference, of placing fingers on the fret markers – rather than just behind). This produces the classic fretless tone in spades and – combined with the “mwahh” on each string – the bass has a wholly different, (“woody” and melodic) character – directly compared against similar, fretted Precision basses.
Of course – the pickup magnets might still be pulling on the strings, and on a fretted guitar – that too can sometimes create wierd goings-on with string vibration. The last task in the setup process – is to raise, or lower, the pickup heights – so that when each string is played at the highest fret – the pickup poles are set a certain distance underneath. For the bass side string – that’s about 2.8mm… For the treble – 2.0mm. Adjustments are made by turning the height adjustment screws at each side of the pickups, and these work against the natural action of the neoprene “springs” below. Once the pickup heights are correctly set – the “ashtray” covers can be re-mounted.
Setup finished – the bass is then allowed to “play-in” over a period – to allow for natural “settlement” – especially of the truss rod adjustment. If any subsequent adjustment is required – I’ll have to re-assess and adjust everything after that point in the setup process… (string height, intonation and pickup height). Again – it’s all about a correct balance of variables, and the setup process, (steps carried out in the correct order), is designed to precisely set each variable in relation to the others.
Garageland 