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For Sale John East "J-Tone" drop-in preamp!!

Discussion in 'For Sale: Parts, Strings, and Accessories' started by RockBoxBass, Dec 2, 2019 at 6:28 PM.

  1. RockBoxBass

    RockBoxBass Supporting Member

    Drop in. Vol/Blend, Bass/Treble a-p/passive tone.black knobs, chrome plate..$165 shipped CONUS ONLY

    J-Tone - Pure & Simple
    • Pure Classic J Tone
    • Full passive & active
    • High performance musical EQ

    Retain the original sound of a J style bass with a modern active EQ in the same preamp - no changes to your bass required!
    John East created the J-TONE pre amp, replicating the authentic original passive wiring of the J style bass with a high spec active EQ. It's designed as a direct drop-in replacement, including a place for the battery. It's easy to fit at home using basic tools, no soldering, no physical changes to the instrument.

    The passive wiring is available as either the classic Volume / Volume / Tone, or for those who prefer a master volume - Volume / Blend / Tone. Plug-in tone caps allow additional fine tuning of the passive tone control.

    The active EQ is simplicity itself, incorporating highly responsive bass and treble controls, taken from our new high end UNI-PRE system. Internal edge wheels allow individual custom voicing for both the bass and treble control spectrum. Instrument qualities can be enhanced in conjunction with tone-shaping to match playing styles.

    Summary of Features & Basic Spec
    • Classic Volume / Volume / Tone passive path version, replicating original J style wiring.
    • Volume / Blend / Tone version for those who prefer a master volume.
    • Push-Pull active/passive on passive tone.
    • Class A FET input stage for great sound quality, with master gain trim preset adjuster.
    • Highly responsive Bass and Treble control adjustments in active.
    • Frequency Wheels to set the width of the bass and treble spectrum individually.
    • Passive tone is always operational, in both active and passive.
    • Passive tone has plug-in tone cap to allow easy swapping of the cap value for different roll-off frequencies.
    • Bass control can be set as boost/cut or boost only, with an internal jumper link setting.
    • Screw terminals for all external connections - pickups and grounding, for easy installation.
    • Designed as drop-in replacement for standard J electronics with no physical changes to the instrument*
    • Design allows 9V Battery to mount beneath the preamp in a standard J style bass.

    Basic Response, Gain & EQ Spec
    • PASSIVE MODE: Neutral at response in accordance with passive control settings.
    • ACTIVE MODE: Neutral at response when Bass & Treble controls are set to their centre clicks.
    • GAIN TRIM: Internal Trimmer 0-12dBs setting overall gain of active circuit.
    • BASS CONTROL: +/- 18dBs Cut/Boost with internally adjustable shelf frequency 40–200Hz.
    • TREBLE CONTROL: +/- 18dBs Cut/Boost with internally adjustable shelf frequency 1kHz – 7.5kHz.
    Note: * The J-Tone will fit in the majority of J style basses, but the routing width and depth of cavities does vary, so we can't guarantee it. It's important to check that a 9V battery drops into the cavity close to the jack, and that there's a depth of 32mm.


    Attached Files:

    Last edited: Dec 6, 2019 at 12:01 PM
  2. bassguyky48

    bassguyky48 Supporting Member

    Oct 6, 2009
    Central KY./Danville
    Vol/volume or volume/blend?
  3. RockBoxBass

    RockBoxBass Supporting Member

    bassguyky48 likes this.
  4. 2 band?
  5. Was this ever installed?
  6. RockBoxBass

    RockBoxBass Supporting Member

  7. RockBoxBass

    RockBoxBass Supporting Member

    yes. super easy. no solder..screw connections
    bassguyky48 likes this.
  8. Funkinthetrunk

    Funkinthetrunk Registered User Supporting Member

    Adjustable bass and treble frequencies makes this one of the best onboard preamps on the market. Then throw in the ability to change out the passive tone capacitors...boom!

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