Eroachguitar 09/28/2012

Kubicki FACTOR : Eroachguitar's user review

"One of the best slap basses ever made"

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Phillip Kubicki is a visionary instrument maker. He first began with Fender in the mid 60's researching and developing new designs for acoustic and electric guitars.
He left Fender in the early 70's and began producing his own instruments. In 1983, he introduced the Factor 4 bass, driven by a desire to produce unique, inspiring instruments. It was soon endorsed by Stu Hamm, and Vail Johnson, and demand for the instrument skyrockte, so much so that Kubicki could not keep up with the orders, and consequently signed a licensing production deal with Fender. When the Fender contract expired, Kubicki resumed manufacturing them in his own capacity for special orders.


The Factor 4 bass has a 32 piece rotary cut veneer maple neck, ebony fretboard with 26 jumbo frets, and an eastern soft maple body. All of the hardware and electronics are designed specifically by and for Kubicki, including the pickups, which are a hybrid active/passive design. The stringing and tuning system for the Factor is rather unique, and employs a design where the string ball end, typically anchored at the body, are seated at the headstock, and each string travels over its own saddle slot and is wound around a ratcheting gear mounted in the body. The string is then fine tuned with a threaded post.

What's more, the Factor allows the E string to be dropped to D automatically by modifying the scale length only for that string, giving it two more frets and its own small nut section separate from the other strings. A spring-loaded bar clamps the string at the 2nd fret to produce an open E note, functioning much like a built-in capo that only operates on that string. This makes going from standard tuning to open D tuning and back as easy and quick as flipping or releasing the lever.

Access to the upper frets is generous, and proper string action makes playing in the upper registers enjoyable. Truss rod adjustment is conveniently located in the end of the headstock, and can be adjusted with a medium-sized flathead screwdriver.


The Factor bass comes with either a 4-Way or 6-way selector switch depending on the model and when it was made. This particular model sports the 4-way switch.

This is where things get interesting. The Kubicki factor bass features a hybrid active/passive pickup system, that allows you to switch between two active modes and one passive mode. For controls, it includes a stacked EQ knob to control treble and bass response, and a stacked knob that controls Volume and Pan, which controls the balance between the neck and bridge pickup output. The active circuit runs on either one 9v battery, or two 9v batteries for 18v operation.

The first mode is Standby, which mutes the bass output.
Mode 2 is active mode with presetable boosted mid frequencies. The bass and treble controls are also active here.
Mode 3 is a flat active mode. The bass and treble controls are also active here and can be adjusted.
Mode 4 Passive mode. In this mode, the Bass control acts as a standard tone control. The Bass control is not functional in this mode.

Despite its maple body and neck, the Factor is capable of warm, soft tones, but it truly excels in the high frequency spank and attack. The pickups are punchy and powerful in active mode, and passive mode offers a softer, more traditional subdued tone for blues and jazz runs.


The Kubicki Factor 4 bass is a truly unique instrument, even 30 years after its conception. No other bass employs quite the same set of features or technology, and for that reason, the Kubicki has a sound and a feel that's tremendously difficult to replicate with another bass.

Two design flaws of the Kubicki Factor bass are that the Switchcraft 125B output jack is positioned dangerously close to the preamp circuit board, and in some cases the solder terminals literally touch the board. With much jostling around, this can lead to shorts in the circuit, and as a result intermittent signal and audible pops.

The other flaw lies in the drop D lever. Since it's designed to hold the string at the 2nd fret (like a capo) to achieve the open E note, over a relatively short amount of time the string begins to dig into the fret, and intonation can be compromised and string buzzing can occur.

New custom shop Kubicki models sell for $2,000-4,000, whereas the original Factor models are difficult to find and fetch not much less than that.

If you come across an older Factor bass, I highly recommend buying it. If not, there's always the Kubicki custom shop. You can even get your new Factor bass in your choice of exotic veneer.