Tech Bench: Bridge Building

July 1, 2013

Leo Quan Badass II
Hipshot A Style
AS I BEGIN THIS SERIES OF ARTICLES ON BASS modifications, let me first publicly apologize to the victims of my obsessive quest for tone—P-Basses routed for J pickups, the Stingray I thought would sound great with a P pickup in neck position, the Jazz Bass I thought would improve with molten lead poured into holes cut beneath the bridge … Over the years, thousands of dollars were spent, and thousands more have been lost by desecrating what would now be vintage instruments. Forgive me, Leo.

My purpose here is not to give you step-by-step instructions on how to mod your bass, but to discuss different types of “refinements” that can be done, weigh their various merits, illuminate any potential issues that might crop up, and give you some perspective before you spend $700 replacing parts on a cheapo bass with the false hope of one day recouping your investment.

An effective modification can boost the performance of your bass to a new level, but there is always the chance it won’t. Consider this: An instrument is a combination of elements that work together, so there is no guarantee that a new ingredient will interact the way you expect. For example, my alder/maple Mike Lull MV5 is an outstanding instrument in every way, and its round, vintage vibe works great for much of what I do. But with a Jazz Bass 5-string, I also want the option to get a hi-fi , Marcus Miller-type slap tone as well, and I wasn’t getting it. The Lull has the same wood combination as my treasured ’74 Fender Jazz, a bass that defines the exact sound I want, but one difference (of many) is the bridge. The MV5 came with a lightweight aluminum Hipshot A-style bridge, while my ’74 Jazz had the ubiquitous Leo Quan Badass II. The Quan’s high-density zinc-alloy construction and sturdy engineering gave that bass more sustain, attack, and clarity compared to the lightweight basic Fender bridge.

With this in mind, I swapped out the MV5’s aluminum bridge for the heavier brass version of the Hipshot A model, expecting similar results—but what happened next shocked me. The bass did not magically transform into a Marcus-machine; instead, the clarity and trueness of my once-amazing B string became an overtone-choked mess that resembled a steel drum being played through a flanger. That mod lasted all of five minutes—and as soon as I replaced the original bridge, the bass returned to its former self.


Gotoh Standard
Babicz FCH4
What happened? Any number of factors could have contributed to the mismatch. The MV5’s resonant body is chambered for lower weight, and perhaps the heavier bridge created a bottleneck for the string vibration. That’s one theory. Ultimately, though, it brought back a lesson I’ve been taught many times but have yet to learn: Great luthiers spend years perfecting their instruments; they build them their way for a reason. The heavier bridge would likely produce great results on another bass—possibly even one built the same way—but there are no guarantees. The most important thing is that I did not alter the instrument permanently.

Swapping out your bridge is a fairly common mod, and in most cases you can do it yourself without any alteration to the bass. Check to make sure the bridge’s anchor screws line up with existing holes. For example, stock Fender 4-string bridges attach with five screws spaced .690" apart, and there are several direct replacements that require no drilling, like the Badass II, Babicz FCH 4, Gotoh Standard, and Hipshot FM1. In some cases, you may be able to find a bridge that has a screw-hole pattern that will hide the original holes and/or be hidden by the original bridge if you choose to put it back.

While most 4-string basses conform to the Fender-standard.750" string spacing, if you play a 5 or 6, there are many possibilities. String spacing is measured from the center of one string to the next, and while some manufacturers still use inches for measurements, it is common to see these specs described in millimeters. For example, Fender’s .750" is roughly 19mm spacing, and many 5-string basses use this spacing at the bridge (Lakland comes to mind), while others use 18mm (Lull, Ken Smith, et al). MusicMan 5’s clock in at 17.5mm, but I’ve seen spacing as narrow as 14mm on other basses. Make sure a replacement bridge has the same string spacing as the original, or you may experience issues downstring at the pickups, fingerboard, or nut. Check to see if you need a bridge that allows stringing through the body or not; many new bridges are convertible, meaning they allow for top-load or through-body stringing. Some companies (like Hipshot) offer the same model of bridge in different materials, such as aluminum or brass—but as my experience shows, ultimately it comes down to how a bridge reacts on your bass. One more thing to notice is the height of the bridge’s base plate. The wrong height could prevent you from dialing in the proper action on some instruments (particularly basses with setneck or neck-through construction).

Modding can be fun or torture, expensive or cheap, successful or a bust, and yet we throw ourselves into it every time with the hope that our bass will magically develop a new characteristic we desire. Hey, sometimes it works! And regarding my quest for the Marcus slap tone out of my Lull? As of this writing, I think I have it dialed in. We’ll talk about that next time. Until then, have fun, but don’t cut up your old Fenders!

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