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Upgraded my Yamaha TRB 1005 Lefty

Discussion in 'Basses [BG]' started by Santraginus, Jan 15, 2006.

  1. I want to let you know about a pretty successful modication I recently did on my lefty Yamaha TRB 1005.

    The bass was bought in summer 2004. Even though its playability and sound were quite all right, I was never fully satisfied... there seemed to be something missing, soundwise. And since I read some TB posts about its stock preamp being a bit too far from perfection, I figured out that sooner or later I'd be going to replace it.

    Well, it happened... I started modifying the bass by replacing the stock bridge with a Hipshot Style B. Replacing was pretty easy, although I had to drill new screw holes and filled the old ones with wood/epoxy.
    After that, nothing happened for a couple of months. I was researching the preamp market and was not able to decide what I should get.
    Until John East announced the U-Retro 5-Knob Deluxe. That was what I was looking for: An active preamp with fully functional passive mode and fits the TRB, because it has five knobs.

    My only issue was that I was not able to find good information on the pickups of my TRB... Some wrote they are passive, some stated they are active, and since each PU has 4 cable connections to the preamp board, I could not really figure out how they work.

    So I decided "they are passive"... ordered a U-Retro via Bert Gerecht (Hotwire Basses), picked it up at his place (thanks for the coffee and the Bass Talk, Bert!), and started.

    It turned out to be a pretty easy thing. The U-Retro 5-Knob has cable connectors that work with little screws holding the cables in place. I found that the PU wiring of the TRB is pretty uncomplicated:

    Two black wires: Ground
    Red wire: PU "Hot"
    White wire: PU "Cold"

    I took care to star-ground everything to the output jack ground; i.e. to avoid grounding loops. Battery wiring is easy, just follow the instructions that come with the U-Retro.

    Some trouble I had was installing the pots. The wood was too thick for the pot's bushes to fit, so I had to remove some wood to make it thinner. However, this was again pretty easy, since there is a thin layer of black wood unterneath a "top" of about 7mm. So I removed some wood around the pot holes from within the control cavity - and stopped just at the black layer of wood. Now the thickness was fine for installing the pots.

    Also, I had a bit of trouble with a defective balance pot - but John East quickly sent me a repacement (Thanks again for your help and responsiveness, John!).

    Now, after having the U-Retro installed, the bass feels like a brand new instrument. The output level increased substantially. And the tone... Well, I think that I am not really able to describe what happened. Feels like a thick curtain was removed, and my bass sounds like it's supposed to - everything from passive vintage sounds to bright Marcus-Miller-sparkle is in there, and I have even started to explore. It sounds just so... "present"... again, I can't describe it. Maybe other happy U-Retro users can.

    I highly recommend every TRB 100#-owner to get rid of the stock preamp and bridge... Of course, YMMV

  2. oversoul

    oversoul fretless by fate

    Feb 16, 2004
    Nice going, when I tried this bass the sound was OK, but that stock bridge seemed a little lame for such a good looking instrument, I'm sending this thread to a friend who wants to buy one.
  3. joboatbuilder


    Oct 12, 2010
    Hi read your old post about putting a john east U-retro 5 knob deluxe preamp into your trb1005.

    I've just done exactly the same thing, and was wondering whether you noticed any noise? I get a lot of hiss if i turn the treble up, even worse if I pull the 'bright' knob on.
    I never noticed this with the stock pre amp.
    Have you experienced this? Or do I have a shielding or grounding issue possibly?

    thanks in advance!
  4. Bloodhammer

    Bloodhammer Twinkle Twinkle Black Star

    Jul 7, 2009
    Shreveport, Louisiana
    I wish I hadn't read this. I'm making the final payment on a TRB1005 fretless next week. Sounded fine in the music store, though...
  5. joboatbuilder


    Oct 12, 2010
    just an update, it turned out that the active/passive tone pot was duff. Because of that, it was causing the overall tone to be totally muddy which was why i had to turn the treble up so much and got the hiss.
    John East helped me find the problem over the phone (simply by disconnecting the tone pot wires made it sound SO much better) and so he then sent me a new pot immediately.
    I've now installed it and the change is amazing. I no longer need the treble and high mids right up, so there's no hiss. The tone is fantastic just what i was looking for, and the variations possible are infinite! It is like having a new guitar, and at the same time already knowing the neck etc. :hyper: It's so good to have the option to use the guitar in passive mode (not able to with the yamaha preamp), great for recording, or perhaps if you did run out of batteries half way though a gig:eek:
    think I'll be playing this a lot over the next week!!

    If you're buying a TRB1005, it will sound pretty good, but I really strongly suggest save up some more gig money and then buy a U retro cos it'll sound even better still. ;)

    I really recommend John East who is the nicest most helpful person I've ever come accross, and his product which is really well designed.

    Also a quick note about the unusual yamaha P'ups wires: John says to disconnect and insulate the 3rd (black) wire from the dummy coil. He's installed his preamps on TRBs himself before and did that.
    As I understand it, when they were connected to the yamaha preamp board they actually worked using some circuitry to create the opposite to the main coil therefore creating a humbucking like effect and so cancelling noise. There is no such circuitry on the U retro board as it's designed for normal P'ups. So if you connect them to the ground they could pick up interference and therefore create noise. so therefore the p'ups now become single coil, so I have copper foil lined all the cavities in case to avoid any extra noise.
    If I've got this wrong then I'm sure someone more knowledgable than me will tell us!! :eyebrow:
  6. Great you fixed it!

    Well, regarding that bass: I was really really happy with the sound of my TRB, as well as the preamp... Until I got myself a Sadowsky, that re-defined what I expect from a B-string. So I sold the TRB.... but still: nice bass, and the East preamp really made it shine. Sad that Yamaha doesn't seem to put too much effort in their preamp designs.... I really loved the option to go passive and the added tonal options I got with the U-retro.
  7. Smit_Dogg


    May 17, 2009
    Cumbria, UK
    Im looking at doing the very same thing with mine, switching out for a hipshot B. What I'd like to know is, what size string spacing did you get as i realise they do these in different sizes, (i'm actually unsure of the string spacing on the yamaha stock bridge, but all i know is its tighter than i like)