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Bart NTMB questions

Discussion in 'Pickups & Electronics [BG]' started by Corwin81, Mar 5, 2004.


  1. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    I've got a 3 knob NTMB pre-wired with the mid switch. There are three modules, but the instructions/diagram only show two. I'm under the impression that the controls are volume, mid, and treble/bass(stack), but the middle pot is a dual gang(but different value than what they call for the blend pot).

    Can anyone help me figure out what this arrangement is?
     
  2. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    Are you sure the middle pot is dual ganged and not a center detent blend pot?

    Given the three modules, I'm guessing it's their preamp with active blend. My deductions are based on this diagram: http://www.bartolini.net/instructions/electronics/ntmb/ns2tmb18.htm

    Your pickup hot wires would be wired to the yellow and orange wires on the left most module. I believe left most pot is mid, middle is blend, and right is bass/treble and the switch is mid freq select (probably 250,500,800). There's no volume pot in this, the green wire goes to hot volume pot in, looks like you'd have to supply your own. Also, because of the active blend, I don't think you'll be able to have an active/passive bypass switch.

    Just curious, where did you get this? I haven't seen Bart sell a prewired harness like this before.
     
  3. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    according to the diagram I found, I think the first pot is volume and the second blend, then stacked bass/treble. I fail to see a mid pot due to the colors of the leads and what not.

    I got this preamp on eBay.

    EDIT:
    Upon closer inspection, it looks as though the previous owner did away with the mid pot and wired two small resistors to the switch as a fixed mid "pot".
    I'd actually prefer to do away with the blend since I'm using it in my OLP MM3. How would I go about doing that?
     
  4. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    could you take another photo with the components more cleanly separated, otherwise it's hard to tell
     
  5. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    The picture I posted was from the Ebay ad. I don't have a digital camera.
    The preamp does look like what you described though, except a 9V version if they made one. Not sure how easy it would be to get rid of the blend though unless it'd be feasible to be able to blend the two coils(it's currently volume/volume/tone for some unknown reason on a MM5 type pickup). Then I'd have to drill a hole for the new mid pot or get a Stingray5 pickguard if they even fit a OLP.
     
  6. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Once you figure out what you've got (that's an excellent pic but hard to decipher remotely), which shouldn't be difficult using the bart.net diagram at that link, I'd run the thing as is as an outboard preamp (at least as a trial) before I went jacking around with it any more than it'd take to get it to fire - which looks like a couple jacks and maybe a volume. I always figure someone ran it that way for a reason and since it's already there, why not see what it does as is. I've got an NTMB (but no third module) I run as an outboard. You don't have to mess with your bass and you can use it with any bass. In fact, I'm in the process of converting all of them to outboard and go passive on the pups. But if you sing, outbaord could be a problem. Things get real ugly real fast when I sing.

    For what it's worth.
     
  7. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    I'm not sure how to get rid of the blend control though. The two volumes on a MM pickup is pretty dumb and blend would probably be dumb as well, unless it'd be better/more usable on a better MM5 pickup
     
  8. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    I'm no tech but have lots of Barts I've wired. From what I can gather the yellow lead to the blend and the green to the volume are interchangeable - and there are bart diagrams that flop them for TCT preamps. For a single volume, running the green from the volume pot to the tip of the jack (where the orange wire should currently be) and then running the yellow from the blend to where the green was (left lug volume) should work. I've done as much and it worked, but iit was n making the NTMB into an outboard, so I had to run from the center lug of the volume to the input jack of preamp (2 jacks in outboard). You would have nothing there but the circuit should be completed regardless through the grounded right lug of the volume. At worst, I suspect you may get nothing.

    Thats for the standard 2 module NTMB that I have, that extra module may require something different. But if you have no wires left over you should be good to go.

    I suppose it's possible to damage something wiring onboard electronics wrong, but I haven't hit it yet. And if anybody could, I'd have been there and back - gaurantee. They're pretty indestructible. However, I'd say you could damage your amp so I always keep the volumes down and ready myself for a quick shut down as indicated - which is a good idea regardless when you first fire somethng new up. I also have an old amp that gets first crack. If it's clean and works, I go to the good stuff.

    Maybe one of the sharper dudes can second this fix or correct it.
     
  9. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    There should be a yellow wire coming from the blend pot to the middle/largest unit. You can wire your pickup hot to that, making the blend pot redundant.

    If you're putting this in a Ray type bass, space is going to be tight under the pickguard.

    Note: it's really hard to help without another photograph showing the current wiring : so I can't be responsible for any damage you do as I'm giving advice based on past experience and basically sight unseen. This isn't one of the standard harnesses that Bartolini sell from what I can see.
     
  10. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    hmmm, I suppose I could always make it a OLP/Lakland and put a Jazz neck pickup in there. I've got a spare Bartolini and use the blend.. I don't care how much I have to rout under the pickguard.
     
  11. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Yeh,

    David's right I think. I've been jacking with these outboards so much lately I forgot all about the pup wire, since an outboard doesn't have any. The wiring I was suggesting would of course have the pup wire going to the center lug of the volume pot, not without wire as I had stated before. But Dave's would be the simplest. Wouldn't think the sound would be any different.

    I keep my bass alterations as reversible as possible. When it comes time to sell, people won't pay for the upgrades and they're usually looking for a bass that sounds like one they've heard - stock. So I always keep the original guts and pups and reinstall them come selling time and then sell the upgrades seperately and at minimum break even. In my experience the dominant sound of a bass comes from the electronics, so you could install the upgraded electronics in another bass if you liked the sound and be close enough to work with.

    So obviously I haven't done much routing. But I'm guessing there's a good chance that removing meat from the body would take out some bottom end accordingly. I have a bass that's a real thudder right now and have thought about removing a substantial amount of wood but I'm reluctant to do so for that reason - I don't want to lose that sound. And I don't think I'm willing to do so for sake of experiment.
     
  12. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    so if I connect the yellow wire straight to my pup and take out the blend/third module, it'd work?
     
  13. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    What you've got is an NS2TMB-18. Diagram at Bartolini.net may help. The third unit is a buffer. I picked one up too that I'm going to wire as an outboard. I'm going to pull the blend pot too so if you don't figure something out from the diagram, I'm going to get to it later and I'll answer your question then if someone doesn't do it in the meantime. Pressed for time on the moment.
     
  14. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Well I jacked with that thing for several hours last night, and it's not an NS2TMB. That's just the link page at Bart that Anthony shipped.

    You should be able to retain the buffer by using either the yellow or orange wire and going to your pup and capping off the other. The green and blue wires are outgoing, so you can connect one of those wires to yellow that went to the blend pot then capping off the other outgoing. You'll have to go trial error at which of the outgoing wires works. For what it's worth, you can also run a mid pot off that switch and then you not only have the switch ranges but you can moderate it with the pot (that's what I did). Also you could just run your pup wire to the yellow off the NTMB module and x the buffer altogether (that should definitely work). There's also the possibility that the wires I said to cap may either need to be connected to each other or grounded. You just have to play with it and see what happens.

    I don't think I've got the buffer working but I'm not sure. Rigging up this as an outboard you have no pup wires. I just tied the incoming wires to the buffer together and did the same to the outgoing and left the hot wire and the ground hooked up as it came - cause I got output that way. I'll have to see if Anthony knows anything. Apparently he wired these up cause that switch ain't normal Bart wiring.
     
  15. nemo

    nemo

    Mar 19, 2004
    Czech
    Hello Corwin81, its 8 months later..
    I dont know in which situation you are with your preamp now, but I know what you have got!!

    Its most probably the custom Bart preamp from MTD Grendel. I have EXACTLY the same wiring in my newly purchased Coral Blue baby :cool:. Pots are volume, pups blend, stacked bass+treble and the three position switch is for mids 1kHz up, mids flat and 1kHz down. This is non-standard configuration custom made for MTD. The biggest black box is marked NTMB.

    Yeah it is 8 month later so I suppose you have already figured out your way, so this information can be totally useless.. nevermind..

    Actually I am thinking about replacing this 1kHz mids switch section with stacked pot for sweepable mids freq and mids gain for more tonal flexibility (stacked pot - so I just can use existing selector hole and dont need to drill another one).
    I know that standard setting for NTMB is mids freq. selector and mids gain pot. No diagram for sweepable mids is available.
    So let me please ask you guys, did anybody of you tried to wire NTMB with sweepable mids freqency? Thanks.
     
  16. luknfur

    luknfur

    Jan 14, 2004
    DIXIE