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

SKU:Uni-Pre 4-Knob


  • 3-band: 2-pickup, 4-knob
  • Volume/Blend Stack - Treb/Bass Stack - Mid/Mid Freq Stack - Passive Tone (A/P Push-Pull)
$325.00 - $350.00
$325.00 - $350.00

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Uni-Pre 4 Knob

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.
  • Question: Where Can I Buy a John East Uni-Pre 2-Pickup 4-Knob 3-Band Vol/Bl Stack - Treb/Bass Stack - Mid/Mid Stack - Tone P/P A/P?

    Answer: You can buy this from Best Bass Gear by Calling 877-839-3531 or Emailing us at or chatting with our Bass Techs


    Rate and Review this item
    Verified Buyer
    Now I have a new favorite bass
    By Paul
    I put this in a Zon Sonus 4 which required drilling 2 holes, but it turned out great and I love the new tonal possibilities. This is the first time I’ve ever modified electronics on a guitar, but I do have some experience soldering so I decided to give it a go. The only soldering was to the input jack since the one included was too short for my bass. I made a mistake on the 9v wiring which caused the battery to drain, but quickly corrected that and all is working and sounding great!
    Verified Buyer
    John East Uni-Pre does it all!
    By Curtis
    I have in all my basses because I know John's stuff and so I have the tone that I'm accustomed to. However, this adds more to the spectrum! I think even 'passive' players will agree that versatility is a great thing to have in your arsenal.
    Sound guys don't complain (and thats rare), other band members compliment (rare too) and all goes well (which makes the listeners happy).
    Kudos to John East for looking after the bottom end!
    Verified Buyer
    John East Uni-Pre : Homerun from across the pond!
    By Alex Mouroulis
    The pickup balance feature is the primary reason to rock this preamp. This allowed me to dial in a ton of bridge pickup on my J J configuration. Though I play this bass primarily in passive mode, now I have a much more modern sound on tap with one click. I went with the flat setting (no pre-shape) to keep the sound pretty honest. The bass window adjustment is a bit tricky to adjust at 1st, but once dialed in to the right frequencies, becomes very usable. Mid sweep and boost I adjusted the frequency once and is very useable. The treble is a bit crispy, I may not have the shelving adjusted correctly yet. I do play with the tone control wide open for the most part. That could be an influencing factor on my treble perception. I did pay a bit more to go with BBG but Max's time and advice was priceless. The follow up pre and post sale makes it well worth it. I am very pleased overall
    Verified Buyer
    Worth every penny!
    By Keith F. Kelly
    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!
    Verified Buyer
    great preamp.
    By the mauler
    This is a top notch preamp. I am enjoying the new possibilities it grants me and this bass. Installation is very simple. I recommend you use copper foil/tape to shield/ ground your instrument- and don't lose the jumpers!
    This unit sounds clean, quiet, and it's operation is very smooth. It gives the bass an exciting tone and sparkle without changing the overall tone and feel of the bass much.
    The EQ is voiced where I like it. I love the bass control's restraint. It gets big big big, but doesn't overpower the other frequencies or the tone of the bass itself. The bright pull is voiced ideally for that top sizzle without having to crank up all the highs in order to get it. Very slick. The high is high, not high-mid, if you know what I mean. I like that.
    I got the mid sweep, too, which is also very quiet, clean, and voiced for pretty much all of our needs. it can pump the low mids for a punchy motown groove or cut the high mids for a contemporary slap sound. Plus, at center, the mid control is neutral. The midsweep is worth getting, in my opinion. Most preamps offer a fixed or switchable mid frequency. This is design offers more flexibility.
    A cool feature of this preamp is that you can use the trimpots to gain up or down each pickup individually. This allows you to make the bass hotter, but also to balance the output of each pickup. This is a great feature for my bass, which has mismatched pickup outputs. However, this feature is bypassed in passive mode, which is another reason I'll not use passive mode unless the battery dies.
    I usually play passive, but this preamp doesn't really support passive mode. The passive mode works fine (even with no power, if your battery dies!) and sounds good/clean, etc. But the active/passive modes are very different in gain/volume. You can't go from passive to active on the bandstand without a major change in gain. Even with the trimpots at the lowest setting, the active mode is hotter than passive. I'll only use the passive mode when the battery dies.