Bartolini RT4CX-B 4-String Original Bright RT Soapbar Neck Pickup

Bartolini RT4CX-B 4-String Original Bright RT Soapbar Neck Pickup

The Bartolini RT4CX-B is the neck-position version of Bartolini's Original Bright RT soapbar, designed as a replacement for 4-string Tobias® Classic and Killer B basses. It combines the depth and punch Bartolini is known for with a brighter, more articulate top end, while its radiused housing is designed to match a 14" fingerboard radius.

The matching RT4CX-T bridge pickup is also available separately in our Reverb store.

DESCRIPTION

The Bartolini RT4CX-B is a 4-string Original Bright RT soapbar designed as a retail replacement pickup for Tobias® Classic and Killer B basses. It combines the depth and punch Bartolini is known for with a brighter, more articulate voice that helps your bass cut through the mix.

Bartolini's Original Bright voicing retains rich lows and powerful low mids while adding a crisp high end, balanced output, and flatter frequency response. The result is a punchy, precise, and modern Bartolini voice that complements the natural character of your bass.

The RT4CX also features a radiused top designed to match a 14" fingerboard radius and uses a passive dual-coil humbucking design with a 4-conductor cable.

This listing is specifically for the RT4CX-B neck pickup. If you're building a complete set, we also stock the matching RT4CX-T bridge pickup separately in our Reverb store. The neck and bridge versions are designed to balance well together.

DIMENSIONS & FIT

Position: Neck
Shape: RT 4-String Soapbar
Length: 4.06" [103mm]
Width: 1.17" [30mm]
Thickness: 0.72-0.82" [18.3-20.8mm]
Additional Cable Clearance: 0.15" [3.8mm]
Top Radius: 14" [356mm]

Mounting: 2 holes on the bass end and 1 hole on the treble end for #4 pan head screws.

Designed as a replacement for Tobias® Classic and Killer B basses. Pickup dimensions and routes can vary between instruments, so please compare these dimensions and the mounting pattern with your existing pickup before ordering.

TECHNICAL

Model: RT4CX-B
Position: Neck
String Count: 4
Voicing: Original Bright
Pickup Type: Passive Dual-Coil Humbucker
Coil Structure: Dual Parallel Humbucking
Cable Type: 4-Conductor Cable with shield and bare drain
DC Resistance: ~2.3KΩ each coil
Resonant Frequency: ~6.1kHz
Sensing Width: 2.36" [60mm] Max

Magnetic Circuit: Carbon steel, brass, and copper powered by ceramic (ferrite) magnets projected shallow for wide aperture.

Coil Polarity: Neck coil South and Bridge coil North.

WIRING

The RT4CX-B uses a 4-conductor cable with shield and bare drain, providing flexibility when integrating the pickup into your bass.

Refer to the Bartolini RT4CX wiring diagram for complete installation and wiring information.

WHAT IS THE TONE OF THE BARTOLINI RT4CX-B?

Bartolini Original Bright soapbars are designed for players who want a brighter, more articulate voice while retaining the depth and punch Bartolini pickups are known for. They deliver rich lows and powerful low mids along with a crisp high end that helps the bass cut through the mix.

Compared with Bartolini's traditional Original Soapbars, the Original Bright design has a higher resonant frequency with a smoother peak, producing balanced output and a flatter frequency response. The additional treble response adds complexity at higher frequencies for a more aggressive bite and growl.

The result is a punchy, precise, and modern Bartolini tone with strong note definition. Bartolini notes that this voicing has been used by prominent bass builders and works especially well when paired with an onboard preamp.

As always, descriptions of pickup tone are generalizations. Your experience can vary depending on your bass, strings, electronics, amplification, setup, and playing style.

WHY BUY FROM FAT BASS TONE?

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We specialize in bass pickups, preamps, electronics, and other tone-shaping gear. If you have questions about fitment, wiring, or choosing the right Bartolini pickup for your bass, send us a message and we'll be happy to help.