The John East preamp club

Discussion in 'Pickups & Electronics [BG]' started by datsaxguy, May 16, 2013.


  1. Cody Farwell

    Cody Farwell

    Mar 8, 2020
    LA
    Hello!
    I'm thinking of ordering a UNI 4 preamp for my 2016 Fender Deluxe Jazz V.
    Will this fit without routing? I was thinking about the Retro, but I prefer the frequency & passive options of the UNI-4. Has anyone run into trouble fitting the UNI into a Jazz cavity?
    Also, is it safe to assume the UNI-4 run at 18v?

    Thank you!
     
    Nuage420 likes this.
  2. Don Vitos

    Don Vitos

    Feb 22, 2018
    Yes i think that will fit it. I installed the Uni in my Precision ultra and fits tight but worked.
    Run at 9v.
     
    Cody Farwell likes this.
  3. Cheers,

    I think you will be OK going from one preamp to the Uni Pre 4. (Pics are always helpful!)

    I see nothing that East states as 18 volt operation in any literature on the Uni Pre.

    I do not see a reference in the schematics for optional 18 volt operation.

    Assume 9v NOT 18v. But, could have no need for 18v for optimal performance!
     
    Cody Farwell likes this.
  4. Cody Farwell

    Cody Farwell

    Mar 8, 2020
    LA
    Yeah, I couldn't find anything either for the UNI Pre- though, on the J Retro page, it states at the top: "That said, all units are designed to operate up to 18V in which case a separate battery compartment will be necessary with most J-Style basses."

    I guess that's why I assumed!

    Thanks for the responses!
     
  5. Gotcha!

    I only looked at Uni Pre.

    I played J-Retro 01 for 5 years in an '08 Fender Am. Std. Jazz on 9v and loved every minute of it!

    Good luck!
     
    Cody Farwell likes this.
  6. ShawnG

    ShawnG Supporting Member

    May 2, 2020
    Ft Worth, TX
    It will run on 18v.
    I believe (but standby to be corrected) 18v gives more headroom to the pre-amp, but actually reduces battery life.
     
    bigtone23 likes this.
  7. Geri O

    Geri O Endorsing Artist, Mike Lull Guitars and Basses Gold Supporting Member

    Sep 6, 2013
    Florence, MS
    Not to be contrary, but I do 2 batteries with my J Retro Deluxe and it seems to be about normal. I’ll have to look, but I can’t remember if I wired them in series for 18V or in parallel for 9 volts with 2 batteries.
    Whatever, I’m seeing an easy 4 months of life before they drop below 8V (individually) and I change them out for peace of mind.
     
  8. flojob

    flojob Gold Supporting Member

    Oct 15, 2011
    You might want to ask for measurements on those preamp boards. I have the unipre 5 and it's pretty bulky in a mtd kingston 6. It's was doable, but for me the components required some finesse and dictated my knob layout somewhat
     
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  9. powerplant

    powerplant

    Apr 8, 2019
    Sweden
    Got a MARUSZCZYK frog that I got "updated with a John east uni-Pre. Sounds fantastic. 9V operation. I have not changed battery yet (four months) and I practice about and hour a day.
     
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  10. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of East Tone UK Ltd
    Just to confirm, all our units are designed to work on 9V or 18V. The only modification is to add another battery connector.

    Doubling the voltage doubles the headroom (an additional 6dBs) and the current consumption will increase slightly.

    We'll add this message to each individual product spec so that it's clear. The fact that we supply all products with just one 9V battery connector, tends to belie the fact that 18V operation is fine.
     
  11. XLunacy

    XLunacy

    Nov 28, 2013
    France
    Just received a Uni-Pre 4 for a new build, can't wait :hyper::hyper::hyper: I've started working out how all the components will fit inside the cavity, because the EQ PCB is quite long :) But it should be fine.

    The preamp will be used with 3 Nordstrand Zen blades, and a rather versatile switching system (described there : 3 pickup switching : please comment (wiring diagram provided)).
    The Uni-Pre was chosen specifically for its versatility, to complement the build, and go all-in in terms of options :D
    Will definitely post samples when it's done
     
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  12. I'm running my uni pre in 24 volts with no issues sounds absolutely amaizing
     
  13. Don Vitos

    Don Vitos

    Feb 22, 2018
    Hi guys! I am really amazed with the preamp but i have a problem.... the mid knob when i go past the middle and i pop or play hard any string makes a noise. if you move the knob a little to the sides, up or down the noise is louder. what can it be? thanks for your help
     
  14. Geri O

    Geri O Endorsing Artist, Mike Lull Guitars and Basses Gold Supporting Member

    Sep 6, 2013
    Florence, MS
    Hi, John, always good to see you helping here.

    I sent an inquiry in about the drop-in Precision Preamp, but can you tell us when they will be available again?

    Thank you!
     
  15. Syl_Funky_bass

    Syl_Funky_bass

    Jun 4, 2016
    Hi guys,

    Two questions about the Uni-Pre 4:

    -Does anyone here have any experience with owning both a Uni-Pre and a SANSAMP BDDI and combining both or having in some way to choose between the two?

    -What/where is the flat position on the passive/active tone control of the Uni-Pre ?

    My gear:
    -2006 Fender Victor Bailey Jazz Bass V (Uni-Pre 4 + Nordstrand NJ5FS)
    -Pedalboard: Boss TU-3->Keeley Bassist comp.->SansAmp BDDI v2.
    -Amp and cab: Little Mark Ninja + 4 Ohm Markbass 410 HF (or MB Ninja 122).

    Thanks in advance for the replies.
     
  16. powerplant

    powerplant

    Apr 8, 2019
    Sweden
    I have the uni pre 4 but not the sans amp thing,
    The tone control question I don't really understand - it is very transparent when it is fully up in both passive and active and it has no dent like the bass/mid/High pots. I hope this answers your question if not please rephrase the question to help a non native English speaker like me.
     
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  17. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of East Tone UK Ltd
    -What/where is the flat position on the passive/active tone control of the Uni-Pre ?

    When the knob is set fully up, that is the most neutral setting for the passive tone control.
    (The above applies to most passive tones in bass guitars)

    A conventional passive tone can only cut the high frequencies. So without boost, there is no flat setting at 50% like most EQs, for example.
    (There are some passive tones with resonator circuitry, which can create a boost peak)
     
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  18. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of East Tone UK Ltd
    Apologies if you didn't hear back from me so far, Geri.

    We don't have a P-Retro release date yet due to work necessary to redesign the rechargeable battery system, the original is no longer available.
     
  19. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of East Tone UK Ltd
    * Can you tell us what the preamp is, please? Is it a UNI-PRE?
    - Are you working with 1 X 9V battery?

    * Do you have a lot of boost dialled in too, when you are playing hard?

    * If the volume is at max, does it go away if you back off the volume?
     
    Nuage420 likes this.
  20. Don Vitos

    Don Vitos

    Feb 22, 2018
    Hello John thanks for you answer!! Yes it’s a UNI PRE 4
    The problem did not exist before. It started now.
    1- yes I am working with 1x9v.
    2-no the boost is in the half.
    3-no if I back off the volume the noise continue only when I pop or play with the finger strong or hard. If the mid knob is in the first half the problem does not exist.
    Thanks again.
     
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Jun 24, 2021

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