John East Uni-Pre 2-Pickup 4-Knob 3-Band Vol/Bl Stack - Treb/Bass Stack - Mid/Mid Stack - Tone P/P A/P (Black Knobs)

SKU:BBG 6842


  • 3-band: 2-pickup, 4-knob
  • Volume/Blend Stack - Treb/Bass Stack - Mid/Mid Freq Stack - Passive Tone (A/P Push-Pull)
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Uni-Pre 4 Knob Black

2 Pickup, 4-knob

  1. Volume/Blend Stack
  2. Treble/Bass Stack
  3. Midrange/Midrange Freq. Stack
  4. Passive Tone (Push/Pull for Active/Passive)

The Uni-Pre 4 Knob is a new generation bass preamp system from East UK.

It's a brand new design that sets new standards with unique features, designed to fit virtually any bass which has 3 knobs with rear cavity electronics.

It also requires a toggle for active/passive switching.

Its main components are a Volume/Blend module and EQ.

The Volume/Blend has totally independent dual active and passive signal paths, controlled simultaneously with a conventional knob set.

The EQ module allows internal voicing adjustment for the treble as well as the lower and upper bass frequencies.

This is in order to allow finely tuned focus on the most crucial bass spectrum.

Modular construction makes for easy installation, with simple plug connections between modules.

External wiring, such as pickups and power, are simply connected using screw terminals.

The potentiometers have 10.0mm threaded bushings designed for rear cavity mounting in the bass. Flat wire connections to the potentiometers and toggle switch allow for a flexible layout.

The preamp comes fully wired including battery clip and Switchcraft jack.

For ease of installation, pickups are connected via screw terminals.

A ground wire will need to be connected to grounding points such as the bridge and any internal shielding.

Out of the box, just connect the pickups using the screw terminals, snap in a battery, and you'll get sound.


  • Totally independent active and passive signal paths guarantee completely smooth blend when set to active.
  • Custom designed pots allow optimal placement of all controls within active and passive signal paths.
  • Class A FET input stages for great sound quality, with two gain trim preset adjustments for each pickup.
  • Operational response of Bass Control can be set internally at both the lower and upper ends of the bass spectrum.
  • Treble Control with internally adjustable frequency voicing, plus Bright as a pull switch.
  • Mid Control with Frequency Sweep.
  • Overall response can be set as flat or with pre-shaper contour, which adds some warmth and sheen.
  • Modular concept allows for easy installation and replacement of parts should that ever be necessary, all with pluggable connections.
  • Screw terminals are used for all external connections such as pickups, power and grounding, for easy installation.
  • Reviews

    Rate and Review this item
    Verified Buyer
    Worth every penny!
    By Keith F. Kelly from on 7/20/2016
    I've done my own maintenance and upgrades on all my own basses for years. I have a Schecter Stiletto Custom-4 that came with those commonly-found crummy passive EMG-HZ pickups and the equally crummy EMG digital preamp circuit. Shortly after purchasing it, I replaced the innards with Delano pickups and a BassMods preamp (which was recommended as a cheap-but-good preamp option in the TalkBass forums). The pickups I love, but the preamp was always a mess of problems; the BassMods preamps use low-quality wiring and potentiometers susceptible to noise and interference, and the preamp "brain" itself is giant sealed black box nearly the size of a a soapbar pickup. The preamp was so awful that I ended up setting that bass aside and never gigging with it -- which is a shame, because it's a great instrument and the Delano pickups are fantastic. So recently I finally decided to suck up the high price and buy this John East preamp to install instead... and WOW, what a world of different in terms of quality! This preamp is compact, well-thought-out, and very easy to install, and comprised of very high-quality components that function exactly as you would expect. Now I can gig with this bass again and depend on it!