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Yamaha BBN5a - BBEast preamp replacement

Discussion in 'Pickups & Electronics [BG]' started by ivan74, Dec 18, 2017.

  1. ivan74


    Dec 18, 2017
    Hello everyone.
    Got this great bass for about two years. For the most part, i love it. Great action and feel, well balanced, very very well built (still perfect despite the age) and for the most part, it sounds great. The fingerboard felt too big at first, but i got used to it. Its now replaced the music man as my main bass.
    What i really dont like its the preamp and i want to replace it.
    Problem is that, after searching and reading a lot on the matter, i couldn't find anyone that was able to do it. Some did it, but ended up with volume or noise problems or both. And most people just ended up replacing the whole thing (preamp and pickups), because aparently, the pickups and the preamp in this bass are really designed as a whole and dont work well with other.

    Now, my question:
    Did anybody suceeded in replacing ONLY the preamp? and if so, how did you do it?

    I know i could replace the pickups too, but replacing the pickups would be a blind guess, i just don't know how some new pups are going to sound in this bass. I´ll do it if i have no other choice, but first, want to know if the preamp replacement is possible.

    Well, at the end, that got pretty long. Sorry. I know this bass its not that common, but any info on the matter would be greatly appreciated.

    Thanks in advance.
    Jimmy Riot likes this.
  2. Stupid question time. Have you tried different type strings ? What sort of sound are you after ?

  3. ivan74


    Dec 18, 2017
    Stupid questions are the answer a lot of times, but im afraid not this time.
    Besides, i like the overall sound of the bass. Ended up with the DR Fat Beams, wich make the mids less honky.
    I just want more control of the mids to sweet them up a little, and specially, i want to get rid of the noise, wich for recording is too much, specially using one of the two mid presets.
  4. ivan74


    Dec 18, 2017
    Well, maybe i should replace the pickups too.
  5. ivan74


    Dec 18, 2017
    Bumpin this once more. I've decided to replace the pickups. Preamp replacement seems too dificult.
    If anybody has replaced the pickups in the bass, any info on the matter would be great. I´ve been looking around and found that the EMG 45 size fits almost perfectly. Pickups most easy to find here are EMGs and Duncans, maybe Aguilar too, but Aguilar and Nordstrand are a little expensive. EMG's would not need preamp at all, so maybe i should go for a pair of EMG Js and add a preamp later if necesary.
    Thoughts on the EMGs (or experiences with pickups in this bass)?
  6. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    A pickup is just a coil of wire and magnets. I fail to see how something so simple can only work with one preamp. It's possible, I guess. How about measuring them with am ohm meter and tell us what you get. I suppose they could be super hot or the opposite. But that's really all the preamp gets is a hot signal or not. Then the preamp does the rest.
  7. ivan74


    Dec 18, 2017
    Shouldn't be really that complicated. But havent found anyone that got succes with this particular bass.
    I know nothing about pickups and electronics, but having searching a lot on this, people who tried the preamp replacement, ended up with problems. (very low output and a lot of noise if i remember correctly). Its got something to do with the dummy coil in the pickups, that its added in the preamp to eliminate the hum. If you change the preamp, the dummy does not work and makes a lot of noise when balancing pickups. Also, the pickups got very low output. Could be wrong, but thats what i remember on the matter.
    I found a post once saying something about puttin resistance between the pickup and the preamp (an aguilar OBP-3) to solve the low output issue, but nothing on the hum.
  8. ivan74


    Dec 18, 2017
    Its a pity, cause the bass sounds just perfect in the second mid preset position, but this is the preset that has less output and makes more noise.
  9. songwriter21

    songwriter21 I have an obsession for wood. The musical kind. Supporting Member

    Jul 31, 2005
    Pittsburgh, PA
    Sponsored by Hipshot
    Wow, this is somewhat shocking, as these basses are supposed to slam with tone. I know that the current model sounds phenomenal, having tried one last weekend.

    EDIT: I see that it's mainly the noise and lack of mid choice. Honestly, why not try some kind of noise gate/supressor, and an eq pedal? I bought a Darkglass Vintage Ultra Bass, with all kinds of selectable mids, and I don't even use the Millennium preamp on my US Cirrus now. Besides, two pedals would be cheaper than replacing pickups and the pre. You've got a pretty solid bass as your foundation...I'd leave the instrument be, and just experiment with out-board stuff.
  10. ivan74


    Dec 18, 2017
    It does sound great. And it plays great. Its an amazing bass.
    I already thougt about the pedal route. The bass has very little noise when the mids are flat.
    The Eden Terranova with two semi parametric mids, or the hartke bass attack 2.
    Gotta look into this Darkglass one. I'll prefer to go without pedals, but if it helps...
  11. Those pickups do NOT play nice with most replacement preamps, because the dummy coil in each is only engaged via the preamp and mixed/summed/whatever to cancel noise - it isn't wired to cancel noise "on it's own". I ran into such issues with my Nathan East (first version) and simply tore everything out and replaced with EMG 45JX - sounded MUCH better to me, but YMMV.

    The Yamaha pickups in the BBN5A (like the East) are essentially single coils + dummy coil. The neck has the active coil on the opposite end of the pickup shell compares to the bridge pickup. They are not reverse wound like on a typical jazz, so even mixing both even without the preamp won't hum-cancel. Stock with everything working as it should, I found it still a bit noisy, and somewhat bland.

    ivan74 likes this.
  12. Yeah this has come up before. I think this is the preamp where all four coils are buffered individually, and the dummy coils have trimpots to sum them just enough for hum-cancelling.

    There are ways around it though I'd say, if you know someone who is into audio electronics.

    Replacing the opamps on the board would go a long way to improving the noise. Have a look at the board, if the opamps are labelled TL062, well there's much better low current ones out there these days. I recently replaced the 062s in a cheap behringer DI and it's so quiet I've used it in the studio.

    The other option is to just use the front end of the existing preamp, and if there's room, add a new preamp. It should be possible to take the signal from the pan pot to another preamp. It's fiddly though as the existing pots would have to be removed. And you'd probably want to disable the power to the rest of the circuit.

    You could also just make four transistor buffers as in the original circuit. They are super simple to make.

    Another option would be to buy two twin-bufffers from bartolini or something and use these with summing resistors and trimpots for the dummy coils.

    You could also try summing the coils passively. Would take some experimentation though...
  13. IVAN I'm sympathetic. I'm very interested in this pickup / preamp discussion for the BB-N5A, because this bass has become my #1 5-string over my vintage ('92) NYC Sadowsky simply because of the playability. I don't dig the BBN5A electronics/preamp/tone though, as popular as it seems to be. To me it's way bass-y, no mid definition, no crisp natural highs. I keep playing it because of it's rock-hard straight solid neck & sustain, but I'm looking to swap out the guts for something better. It can still be active, but even though I've delved deeply to understand the 3-way mid switch & the parameters of the two adjustable mids, I don't like it. Can't find a setting I like, and getting tired of unscrewing the 5 backplate screws to adjust. When gigging or rehearsing it all sounds the damn same. Plus the output is enormous, even for active, but if I don't have the bass knob up it sounds wimpy & I can't blend well. Any replacement suggestions? Bartolini pups w/ Aguilar pre? DiMarzios? I forget what size these pups are (there's a name/category number for them) but there must be some "industry standard" replacements for this sort of thing... What do you all suggest? IMG_1423.JPG IMG_1424.JPG
  14. ivan74


    Dec 18, 2017
    First, i gotta thank Jamie_Funk for his great advice. It was inmensely helpful. I was afraid of the pickup change, cause i could end up ruining a very good bass, but no. It was the opposite. I just installed a pair of EMG J, and could't be happier. Its got the same vibe, but sound its much more clear and open, and very easy to get. No complicated eq or setups. And thats just with the passive tone, with no preamp.
    The sound of the bass now is very close to the second mid preset ive got before, wich i liked a lot, but without any noise and much more clarity and output.
    murphy and Jamie_Funk like this.
  15. Dragan


    Oct 5, 2009
    Bump! I have the same bass like yours, and also not excited about the preamp but l love how it sounds with Aguilar tone hammer pre/di. It slams. I am using it in 1st position on mid pot.
    Previous owner said it is a passive mode which to me doesn't makes sense as it reacts to bass and treble adjustment.
    Edit: l just tried it without battery and it doesn't work, so my guess was right, no passive mode here.
    Last edited: May 10, 2019
  16. Dragan


    Oct 5, 2009
    No need to shout, bro. We hear ya :)

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