Passive-ing out a Thumb NT?

thefitz

thefitz

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Hello friends,

I recently acquired my dream fretless - a 1990 Thumb NT 5 string - from bostonasphalt2. All I had to do was sabotage the Toronto Maple Leafs (but that's another story).

The bass currently has two Duncan pickups (either the SJB-5 or the AJB-5 - not sure) and the STC-3 (A or P depending on the pickups) with an active/passive functionality and a switch to engage the slap contour.

I'm a big fan of the Jaco tone that this bass nails, and am considering switching out the entire electronics setup with noiseless passive Jazz pickups (with open magnets, a la a real Jazz bass) and a V/V/T control setup.

The superfluous switch WILL drive me crazy if I do this... and I do adore the basses current sound. I just think it might end up being THE fretless if I do this. Yes, I can go passive, but there's no tone knob, and I do believe that passive, open magnet pickups just respond differently than ceramic bar pickups.

Any thoughts on this? Has anyone done this?
 
Luckily this is a totaly reversible mod :-) Do it, play it, and trust your intuition...
 
Hmm!!! I'll have to look into this more. Does anybody know of good noiseless vintage pickups that would retrofit?

And boston asphalt2 - if you ever get sick of that P-Nut 2, maybe we can arrange something :P
 
I recently converted my Streamer Stage I to totally passive and love it. I don't have a single regret, and if I did I could switch it back no problem. I have a V/V/T/T pot setup in it, with Nordstrand big singles. It sounds excellent! Nordstrand also makes jazz sized pickups that are worth looking at. Other good makers off the top of my head are Lindy Fralin and Hanson Pickups. Of course you could always go with the passive Dynamic Correction MEC pickups! Hope this helps.

Also, I'm intrigued by your Maple Leafs story.
 
Oh I was just teasing about the Maple Leafs thing, it's just a little inside joke I guess.

I did some investigating, and I think this is what I'm going to do - get a set of Nordstrand NJ5S pickups! They're the same size as the Duncans that are on there.

Now, what to do for electronics? Well, bestbassgear.com, which stocks the Nordstrands, also has a 3 pot, one switch version of the Aguilar OBP-3! V/V stack, push-pull mid, B/T stack, and an A/P switch. That's what I'm going to do!!

I'm going to order these puppies next week!
 
I've been going back and forth with bestbassgear.com, and they had issues over string spacing and the magnets lining up correctly. I'm confident that 2 neck pickups will be perfect - they're the same dimensions as what I already have in there, and the magnets themselves cover 69mm string spacing (the bridge pickups have a little wider spacing). I've measured my string spacing (centre to centre) to be 69mm neck/71mm bridge, so I'm confident.

I'll set the ball in motion soon! Stay tuned!! I have to reveal my other crazy Warwick mod as well.
 
thefitz said:
Hmm!!! I'll have to look into this more. Does anybody know of good noiseless vintage pickups that would retrofit?

And boston asphalt2 - if you ever get sick of that P-Nut 2, maybe we can arrange something :P
Click to expand...

I love that P-NUT2, it ain't going anywhere ;-)
 
Haha, worth a shot.

I'm also considering DiMarzio Area J pickups, as I've heard they're really good, and can get two of them for the price of one Nordstrand.

I'm inquiring about the radius of the pickups - if they're not that steep, I'll go for the DiMarzios. If they're way off (and frankly they appear to be), I'll go with the Nordstrands.
 
Alright!!

I have ordered the Aguilar OBP-3 with a V/V, Mpp, T/B knob config with an active/passive switch, as well as two special order DiMarzio Area J 5-string neck pickups, with pickup magnets that are flush instead of radiused. It'll be a while before this all arrives, but stay tuned!
 
why neck pu's instead of bridge? o_O
obp-3 is a good choice. just make it 18V
 
I got it spec'd for 9V because the bass has a dedicated battery compartment that fits a single battery.

But great question - why two neck pickups???

This gets a little complicated - some companies, like Seymour Duncan, make pickups that have neck pickups that are narrower than bridge pickups. Other companies make pickups that are the same size. Warwick 5-strings need two "bridge" pickups - i.e. 2 pickups that are roughly 3.75" long. That's the length of a Duncan bridge pickup, but not a neck pickup.

This matters on pickups that have open magnets (as opposed to rails, like most modern closed-cover pickups) the most. For Nordstrands/DiMarzios, the neck AND bridge pickups are both the same size, roughly 3.75". However, the string spacing of the magnets is different - 69mm on the neck pickup and 72mm on the bridge pickup. I've done the measurements, and 69mm is perfect. 72mm would have been too wide.
 
battery and electronics cavity in my thumb nt 4 string also seems to be designed for 1 9V battery
but 2 of them fits also normally
I can make a photo later

P.S. i bought obp-3 spec'd for one 9V battery but in result made it for 18V
 
This Thumb is one of the basses that has a separate compartment for batteries, and it fits exactly one 9V battery.

I could have one battery in that compartment and one battery bouncing around in the control cavity, but with passive pickups I'm good with how I have it spec'd.
 
I don't have separate battery compartment in my Thumb :/
 
This one is from 1990, back before the easy access control cover - this one has a screwed on control cover that sticks out, and a separate battery compartment. My 92 Streamers had their batteries in their control cavities, and the easy access cover.
 
Made an account to ask - how did the DiMarzio swap turn out? Did the pole piece spacing work out ok?
 
`

thefitz said:
...............................
The superfluous switch WILL drive me crazy if I do
this ... and I do adore the basses current sound.
............
Click to expand...

A verrrry wise man once said ... maybe even said it more
than once ... and certainly many men after him have also
said it more than once .........

" If it ain't fix, don't broke it ! "

And puh-leeeze, let's not hear from neither nor both of
our two female brethren about the "men" thing. This is
definitely something MEN say ... and have always said.
It is simply not a chick thing. AAMOF it's typically said,
by men, in response to items on a "honey do" list :)
 
`

Whump said:
Made an account to ask - how did the DiMarzio swap
turn out? Did the pole piece spacing work out ok?
Click to expand...

In nearly all instances, pole piece spacing is just
a cosmetic thing, no practical effect.
 
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