A hefty introduction

[Jaco De Lucia]

Hi folks! This is Jaco de Lucia, a newbie to this forum. Just wanted to introduce myself and say hello.

I am a physics and astronomy professor by trade at a local college, but at night I obssess over basses and their workings. I am a huge fan of Paco de Lucia (I play flamenco guitar too) but I am a bigger fan of Carles Benavent, his bassist. He does everything Paco does on a fretless bass with a pick! Recently, he's switched over to playing a fretted 5 string and is making waves with Chick Corea. Killer stuff.

I've recently been modding the heck out of two basses (with a physics background, it's bound to happen--the hours of tinkering and pondering, etc.). The first one is a 3-tone sunburst Epiphone Rivoli (generally an average instrument with great looks)--I took out the stock neck pickup and installed a Dimarzio sidewinder in the neck PU position, and the bridge PU (which was a Mighty Mite) I painstakingly added a 5th pole. I also added a 5th saddle to the bridge and a Steinberger straight-thru tuner to the headstock--it is now a 5 string bass. It sounds like a nice jazzy baritone guitar--perfect for modern flamenco. And it's eye candy.

The other bass is a 1965 cherry-red Guild Starfire bass--it originally came with a Dimarzio sidewinder PU (placed it into the Rivoli above), but the guy who sold it to me had the original Hagstrom pickup for it in a plastic bag. There is only one place for a PU--at the bridge. I took out the Dimarzio, shielded/grounded the cavity, and plopped in the Hagstrom. It is NASTY--the tone is like Jack Casady's on "Bless Its Pointerd Little Head". I decided to do some research and found that I can add another magnet into the Hagstrom. I just did that tonight, and I must say that the tone is even nastier than before! Just IN YOUR FACE tone--edgy, but controllable. That, and a Varitone switch (from Torres Engineering) makes this a very versatile bass. And it looks great--with the f holes and the beat up cherry red finish. This relic plays like a dream.

Here's my 2 cents on bass pickup theory: The magnet is there to magnetize the strings which contain some ferromagnetic properties (most bass strings are nickel or iron-based). The magnetized strings, when set to motion, disrupt the magnetic field in the proximity of a coil of wire--the fluctuations in the field produce current in the wires (Faraday's Law) which is sent as electrical signal to the output of the pickup. The placement of the pickup along the string, the string height over the pole pieces, the geometry of the coil winding, and the strength and focus of the magnetic field all affect the tone of the bass. Too much magnetic field strength, and it attenuates the string vibrations, introducing horrid overtones--it is louder, but the magnet interferes with the vibrations. So you can either get greater sustain or louder output, but not both by fidgeting with magnets in the pickup. The pole piece shape affects the magnetic field distribution, which will also affect the wave shape of the output--small pole pieces will tend to produce triangular-like waves, whereas larger pole pieces will tend to produce a square-like wave. Blades will have an even response, and will tend to not die off as you bend the notes.

If you put a capacitor in parallel with the pickup, it will act like a low pass filter, allowing the tone to become less trebly (this is what the tone knob effectively does with a capacitor and a variable resistor (knob)). Put it in series, and it will cut the low end. You'd think that you don't want to do that, but Rickenbacker 4001 basses do just that with their bridge pickup. A 0.0042 microfarad cap is placed in series with the pickup, to give the pickup less bass response, emphasizing the treble--which is why Chris Squire's tone sounds they way it does--crunchy, but not distorted.

Anyways--I'm not a super expert on bass electronics, but I know what I know. I hope this helps with whatever bass project you are working on. Do not be afraid to try tweaking and modding your instrument (unless it is a prized vintage guitar with a brand name)--just practice soldering a little beforehand, and you too can make your average instrument sound the way you want it. Of course, talent helps too!

If there are any flamenco guitarists out there in the SF Bay Area who which to jam with me--I play fretted and fretless basses and I know my compas, please drop me a line. I am also a proficient rock/jazz drummer (I've been drumming since 1977 and have an adept kick drum foot ala John Bonham) and percussionist (I play flamenco cajon too). Flamenco bass will never really catch on as a trend, but that's okay. I have my niche and love what flamenco bass can do. Playing bass under flamenco chords, playing melodies and chords on bass, using harmonics and harmonic slides--it's all part of the flamenco bass style. I also play a '62 P-bass ala Jamerson and Babbitt. And I can swap trivia stories about Beatles music like nobody's business...

Hope to hear from you soon. Sorry if I was too wordy.