Yamaha TRB-6P Six-String Bass | Part 7

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Albert's TRB-6P: Leveling the Fretboard

My initial examination of this Yamaha TRB-6P Six-String Bass revealed quite a lot, most of which I've already shared with you. What I did not mention was a slightly back-bowed neck and frozen truss rod adjustment nut. I'm glad to report that after many days of applying MultiLube and gentle coaxing, the stubborn nut has finally loosened; allowing the truss rod to relax and neck to straighten.

Before installing frets on this ebony fretboard, I'll have to make sure it's dead flat. I'll also need to sand out as much of the chipping and tearout as possible without damaging the abalone dot markers. After that, there'll be the task of carefully re-cutting the fret slots to the right depth and width. But I'm getting ahead of myself here, aren't I? Okay then, let's see what I managed to get done today.

After carefully wrapping the body in clear stretch film and taping off the top, the fretboard was marked with a carpenter's pencil. Doing this would help me identify any high or low spots while sanding. I started out with 60 grit sanding beams and blocks. Yes, 60 grit is a little aggressive, but the majority of those chips were plenty deep.

This marking/sanding/marking cycle was repeated a couple times until I was up to 400 grit. A final check with my trusty 12" try square confirmed that the fretboard was nice and flat. At this point, I called it done. You can still see those nasty chips, no doubt. However, I believe they're now shallow enough for frets to be seated securely. I'm also happy that the wear marks caused by the A, E and B strings have virtually disappeared. And that, folks, is what I managed to get done today.

TRB-6P All Wrapped Up

Chipping, Tearout and Wear Marks

More of the Same

Fretboard Marked

Sanding in Progress

Initial Result

Another Cycle Begins

After Sanding with 400 Grit

Nice and Flat

Striking a Handsome Pose

V-Style Six-String Prototype | Part 3

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Body and Related Appointments

The body of this V-Style Six-String Prototype appears to consist of a two-piece hardwood back and spalted wood top with cream binding. While the back shares the same translucent dark blue stain as the neck, the spalted top features what is best described as a light "blue burst." Rounding things off finish-wise is a clear gloss polyurethane top coat. 

In keeping with the theme set by the tuners, hardware on this body is predominantly gold. This includes the Bigsby-licensed vibrato tailpiece, TOM-style bridge, single dome control knob; and output jack plate. Of particular interest is the vibrato tailpiece, which is bolted to a metal brace that fits across the span of the body's V-shaped "legs." Truth be told, the late great Lonnie Mack immediately comes to mind. Rest in peace, Mr. McIntosh. 

This guitar left the manufacturing facility with two single-coils, a three-way toggle switch, volume control and output jack. All's not well in paradise, though. Our musician-cum-entrepreneur has removed the bridge pickup as he's not that satisfied with it. He'll be passing me a replacement soon, so no worries. Do stay tuned for future updates on this V-Style Six-String Prototype, folks.

Blue Burst Spalted Top

Spalted Top Up Close

Two-Piece Hardwood Back

Translucent Dark Blue Stain

Left Side of Body

Right Side of Body

Volume Knob and Toggle Switch

Output Jack and Jack Plate

Metal Brace for Tailpiece

Bigsby-Licensed Vibrato Tailpiece

TOM-Style Roller Bridge

Control Cavity

V-Style Six-String Prototype | Part 2

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Neck and Fretboard

This V-Style Six-String Prototype features an unbound dark hardwood fretboard that looks and feels lot like rosewood. The fretboard features a 24-3/4" scale length, 16" radius, 22 medium jumbo frets and pearloid dot inlays. Last but not least, the set-in neck appears to be a single piece of hardwood, most probably nyatoh. It sports a translucent blue stain and clear gloss polyurethane finish.

Unbound Fretboard/Dot Inlays

Left Side of Fretboard

Right Side of Fretboard

Nut to 12th Fret Measurement

Nut to Bridge Measurement

16" Fretboard Radius

Back of the Neck

Set Neck Joint

Yamaha TRB-6P Six-String Bass | Part 6

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Albert's TRB-6P: Electronics

Electronics-wise, hardly anything on this bass is factory issued. For starters, the bridge-mounted piezo pickup is no more. When the BPZ-6 was replaced with a Monorail bridge, along with it went the piezo pickup. As for the YLB-S6JZB ceramic single-coil pickups, they've been upgraded to Bartolini G66CBJDs. The stock onboard two-band 9V preamp is also history, and in its place is a custom-built Bass Lab unit.

Bartolini Pickups

The current pickups in this TRB-6P are Bartolini 6-String Classic Bass G6 Candybars [G66CBJD]. According to the literature, Classic Bass Candybars are passive "inline dual coil" humbuckers comprising "two types of carbon steel, brass, and copper powered by ceramic ferrite magnets." Kindly click HERE for more information on these pickups.

Bass Lab Onboard Preamp

Albert's TRB-6P currently features a custom-built Bass Lab 9V two-band preamp installed in April 2012. This preamp basically consists of a 9V battery power source, stereo output jack, two circuit boards, five rotary controls and a mini SPDT toggle switch. 

Pickup Volume and Tone Controls

Moving on, we examine the layout and functions of the Bass Lab preamp controls. In the pics section below, I've drawn up a diagram of this layout for your reference. Starting off in the upper row from right to left, we have three regular-sized black plastic knobs. These are the Neck Pickup Volume, Bridge Pickup Volume and Master Tone controls, respectively. This configuration is similar to that of a typical Fender Jazz Bass.

Duo-Tone Switch

On the extreme left is a mini SPDT toggle switch which I've dubbed the "Duo-Tone Switch." This switch is wired to the master tone pot and switches between two polypropylene capacitors. To my ears, switching down [Hi] attenuates lower frequencies and results in a brighter tone. This effect is especially noticeable when the Master Tone knob is rolled off completely. Conversely, switching up [Lo] attenuates higher frequencies and darkens the tone considerably.

Active Treble and Bass Controls

Two stacked concentric chrome metal knobs occupy the lower row. On the left is the Treble Control. Rotating the outer ring allows you to sweep through and zone in on a particular treble frequency, while the center knob controls the amount of boost or cut. Turning this knob clockwise from the 12 o'clock detent boosts the selected frequency, and vice versa. Next to the Treble Control is the Bass Control. The Bass Control operates in a similar fashion, albeit on bass frequencies only.

Bartolini Classic Bass Candybar Neck Pickup

Bartolini Classic Bass Candybar Bridge Pickup

Bridge Ground

Bass Lab Preamp Controls

Labeled Diagram of Preamp Controls

Back Covers

9V Battery Compartment

Control Cavity Cover

Control Cavity

Main Circuit Boards

Neck Pickup Volume Pot

Bridge Pickup Volume Pot

Master Tone Pot

Duo-Tone Switch

Bass Boost/Cut Pot

Treble Boost/Cut Pot

Control Cavity Ground Lugs

Stereo Output Jack