NOTE: This information is copyright and must not be used for commercial purposes by any other party. Chris Kinman (c) 1998.

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How I match my pickup poles to different fretboard radii.

Basics: The distance between a string and magnet determines the loudness of the string so one might conclude that to get excellent balance of string outputs the magnets should all be the same distance from the strings. But fretboards are usually radiused (arched / cambered) and since the strings follow that radius we have magnets of different lengths arranged in an arc (ostensibly to match the arc of the strings). However, in practice some strings generate more output than others. For example the non-wound G string of modern sets is extremely louder than any other string, the B string also is somewhat louder while the D string is somewhat softer. That's why we have magnets of different lengths (staggered) to help compensate for the strings that are louder then others, so that all strings sound balanced.....ie they all have the same loudness. Another significant aspect of this story is that Leo Fender designed his fretboard radius for playing comfort, with a tight radius of 7-1/4", which is easy for fingers to form bar chords.

Problems: The traditional stagger of old Stratocasters was originally designed for a wound G string that was predominately used in the 50's and 60's. In the late 60's the Blues influenced music and guitar players began stretching notes upwards by bending the strings. They soon discovered that a non-wound G string could be stretched (bent) far easier and further than a wound one. But a non-wound G string is a rogue and has dramatically more output and the increase in volume means it dominates all the other strings. Pickup manufacturers never caught up to the modern style of playing and retained the old out of date stagger, many still to this day.

However a geometric problem exists with extreme stretching on Leo's 7-1/4" radius fretboard in that strings tend to bottom onto the frets resulting in choked (deadened) notes, particularily in the upper register. Players compared notes and noticed that flatter fretboards like Gibson's 11" radius did not have this choking problem. Realizing the advantages of a flatter radius some manufacturers (who were looking for a gimmick to increase market share) conceived the compound radius. Done sensibly, a compound radius is a clever way to combine the comfort of Leo's fretboards with the aniti-choking properties of Gibson's fretboards. However not all compound radius are sensible and actually create another problem with string output imbalance. The result is the G string is excessively loud and the two E strings are excessively soft when vintage magnet staggers in the pickups are used. Using non-staggered magnets improves balance somewhat but still there is the big difference in output between the G and D strings as well as a significant difference to the other strings.

Solutions: One magnet stagger can't possibly match all the different fretboard radii options available on modern guitars (Kinman Tele pickup excepted, see Teles >additional info). Magnet staggers are set at time of manufacture and can not be changed, so to solve this dilemma I offer two radius options. First is the (fully compensated) stagger in the 7" to 14" radius range that suits most single coil pickup guitars (such as Fender, Musicman, G&L etc, see Table below).

The other has non-staggered magnets made for flatter fretboards ranging from 14" to 20" such as Warmoth compound necks and various other brands of guitars with excessively flat fretboards (see Table below). However the Kinman non-staggered magnet array, although appearing as nothing special, is engineered to help compensate the D string for a more balanced output. It's not a perfect solution but is better than regular non-staggered magnets.

Conclusion: I discourage players from using Warmoths 10-16 compound radius because of the above problems. However USA Custom Guitars make a sensible compound radius 7-1/4" to 9-1/2" that works great with staggered poles, is comfortable and solves choking, the perfect soultion. For more discussion about fretboard radius visit my Perfect Guitar page, fretboard radius section.

The radius range is marked on the base of the pickups as well as on the label in the box. The table below gives you a rough guide as to the radius of some common guitars. If your's is not listed please "Contact Me" to have it included on this page

- RADIUS CHART -

All radius can be supplied in either Right or Left hand.

Check your radius, if you're not sure what it is, better shops and good repairmen quite often have radius gauges that can measure this. If you prefer to measure it yourself, download the instructions and templates below.

INSTRUCTIONS FOR MEASURING THE RADIUS OF YOUR FRETBOARD.

Below you will find a number of files containing a fret board radius gauge which looks a bit like this:

Download (save to disk) and print the gauge (portrait orientation) in a format that your system supports (there may be more than one). Once you have printed it check the length of the straight lines; if they are both 100mm (or at least equal in length) then your gauge has printed correctly.

Using scissors or an artists scalpel, carefully cut the radius out as neat and accurate as possible. Then, after loosening your strings, find which of the templates fits the radius of your fret board the closest. If the curve only touches the middle of the fret board then it is too big, if it only touches the sides then it is too small.

It is important to get within one of our ranges; Standard 7 - 14 inch or Compound/Floyd 15 to 20 inch. Specify which one when ordering or purchasing your new Kinman pickups. The radius range is marked on the display box as well as one the base of the pickups.

The files: