Fender Jaguar Bass
I often wondered why Fender never offered a Jaguar bass in the old days and always thought it would've been cool if they did. For years I contemplated making a version of my own, so when I saw that the started producing one (crafted in Japan) in 2005, I knew that I'd just have to have one. I was a bit disappointed that it didn't have a block and bound neck, and the first few years that they were available in the USA, they only offered them in black and, in my opinion, the gawdy and cheap looking 'hot rod red.'  I mean, black is cool, but if they were going to do a red one, candy red, Fiesta red or Dakota red would have been more appropriate (and I don't even care for red guitars). In Japan, the two colors available were much cooler,  in three tone sunburst and olympic white, both with tortoise pickguards. It wasn't until the last year (2009) that you could get a burst or white one here in the states unless you bought it directly and had it imported from Japan. At first, I had my mind set on a burst one, but them got the idea that, since I love the maple/white/black look on Fenders, that I'd just go with a black one and modify it.

Being recently discontinued (at least here in the US), I figured that I'd better get one before it was too late, so luckily, I found a 2009 one locally on craigslist for a reasonable price. When all of the online dealers had them, they retailed at $1180.00, and often had a 'street price' of $749.00. At the very end of the stock on hand, they were blowing them out at $599.00, which I thought was a bargain.

First impressions:
I prefer the sound and comfort of lighter weight fender basses and my first jag weighed in at a reasonable 9 lbs 4 oz. Even though it's a bit heavier than my other fenders, when worn on a strap it doesn't really feel as heavy as it is, but due to its body shape, it is a little neck heavy.

As is very common, the nut was cut a bit too high (which I quickly remedied) as well as the neck had a bit of a front bow. after addressing those two issues, and adjusting the action/pickups, it played like butter, and the neck was now as straight as any bass that I've ever owned (more than 150 of them).

Time to plug it in. The preamp was noisey, hissing and spitting, so I took the 9V battery out and measured it. it measured 8.6V, and even though it should be enough voltage, I replaced it with a new one and after testing it, all of the hiss and most of noise was gone.

First of all, I prefer the sound of the 60's J bass pickup spacing over the 70's ones (like the Jag bass has) as I find the bridge pickup can be a bit too harsh and brittle when it's that close to the bridge. And when you couple that with the Jag's bright J bass pickups, it's even worse. I removed the bridge pickup and measured it's DC resistance to be 5.68K ohms , so i had a USA fender Jazz bass bridge pickup in my parts drawer and replaced it with that. it helped, having more lows, mids and a smoother top end but, IMO still left something to be desired, still had quite a bit of noise if only using one pickup at a time.

I really like the pickup selector and series/parallel switch, since it yields yet another usuable tone from a standard j bass.

IMO, the preamp is okay, as long as you don't roll either the treble or bass up very high. the highs are very bright, and the bottom can come on like gangbusters, if you roll either one of them in any more than 20%.

The first day, I replaced the pots with USA CTS ones so it would fit the USA j bass knobs (IMO, the japanese ones look cheap).

I decided to try a set of Dimarzio ultra jazzbass pickups  since, for me, this bass just has too much mids and a clackiness in it , and they have been a perfect match for this bass.

The Jag  bass has a nice feeling neck (straight with a nice, slim J bass profile), but I really prefer the look of block/bound jazz bass necks, so that was the next thing that I replaced.
Stock Jaguar Bass
After playing it for a day, I noticed that the electronics had quite a bit of hum, so I checked the continuity of the shielding paint and found it to have a reistance of 70 ohms within each cavity and that it wasn't grounded properly. So, I repainted the cavities with "Nickel print" and grounded them. This lowered the hum level drastically. Now onto some more 'serious' modifications.

The neck:
While I found the stock neck to have a very nice and thin Jazz bass profile, with a good amount of rollover on the edges, I still wanted a block / bound neck, and on a black one, felt that a one piece maple neck would yield an interesting look, so I ordered a new neck from Allparts.com. In my opinion, the Allparts necks are excellent sounding necks and are constructed in the same manner as the vintage Fenders (i.e. the truss rod adjuster is at the heel and the rosewood ones do not have a skunk stripe on the back. Whne the neck arrived, I fit it to the body and installed a set of Gotoh 'Res-o-lite' machine heads. The new heads weigh 5+ ounces less than the originals, which not only reduce the overall weight of the bass, but reduce it exactly where it needs it, at the end of the headstock for better balance. The bass had NO neck dive issues now.
Jag with neck maple neck (test fit):
Since the Allparts necks are a  little chunkier than my '60's jazz basses, and come with a thin poly finish, it was time to remove it and strip the poly. I also shaved it to a thinner 60's profile and added a fair amount of 'roll-over' on the edges. They come with 2mm side dots, so I redrilled them and installed 3/32" side dots as found on vintage fender necks as well. Next, I applied a nitro lacquer finish on it and installed a new jaguar bass decal that a firend custom made for me, since I don't care for blank headstock basses, and the neck neck is made in the Tokai Fender factory anyway.
New one piece maple neck with logo,  nitro lacquer finish and Gotoh res-o-lite machine heads:
I found that the new maple neck sounds much better than the stock one, with a more even, balanced tone with more clarity, transparency and better note definition.
While I usually prefer and recommend to leave all Fender basses stock and original, with the Jaguar bass, I just wasn't thrilled the way that it came in its 100% stock form, and without modifications, I would've ended up just selling it since I already have so many nice stock basses. I really like its vintage look, and love its look even more so now.

Other modifications:
The original Jag knobs just look cheap to me and the pots that they're mounted on are no picnic either, so one of the first things that I did was to replace the pots with USA Fender CTS solid shaft pots, USA Bakelite Jazz bass knobs, a switchraft jack and an original NOS Fender .047uf Cornell-Dubilier capacitor. I also felt that the switches profile protruded too high from their control plates, making them too easy to switch accidently with aggressive playing. The simple fix for this was to install some 8/32" nuts, used as spacers on their mounting screws to lower them about ..150" (more than an 1/8").
Picture showing the 'lowered' switches on the pickup selector control plate:
Being alot more pleased with the new Dimarzio Ultra jazzbass pickups (#DP149), I did find that since they are 'flatop' pickups with all of the magnets being even with the bobbin, I noticed that the A and D strings were a bit weaker in output, since they didn't follow the radius of the fingerboard and action curvature. Back in the late 70's, Leo Fender offered me some steel discs to solve the same problem on my stingrays, so I fabricated some .125" thick discs from some drill stock and used CA glue to adhere them to the 8 inner magnet poles. This little mod yielded a perfect string to string balance without the need for changing my finger style  or using compression to compensate for the volume differences with the stock ultrajazz pickups.

Here's a picture of the pickups with the magnet shims in place:
A little closer shot of the modded pickup poles:
Total modifications:
1. New one piece maple neck (reshaped and lacquered) new fender nut installed w/ USA string retainer
2. Gotoh Res-o-lite  Tuning heads
3. CTS pots and Switchraft jack with new .047 capacitor
4. USA bakelite knobs
5. DiMarzio Ultrajazz bass pickups with pole modification
6. Switches given a lower profile
7. Reshielded and grounded all cavities
I was so pleased that the way that this bass turned out, I bought another black one, but on the second one I decided to go with a block/bound rosewood fingerboard with a matching black heastock. On this one, I already had a set of Seymour Duncan 'Hot Stack' Jazz bass pickups, so I used them in this one instead of the Dimarzios. They have a bit less highs than the DiMarzios, but have a really nice midrange punch to them. This second Jag bass has all of the same modifications as the first one, with the exception of having the Duncan pickups.
Since the headstock is black, I had to have a new decal made that used only silver ink so all of the writing would show up against the black background:
Before and after pics of the second Jag bass:.
Both jag basses after modifications:
I think that the reason that these basses were discontinued was because of them not meeting the expected amount of sales, and I think that there are a number of reasons for that, First, there are many people that think that a Precision or Jazz bass are the ONLY basses that Fender should make and the Jag is a departure from that, but i think that the poor shielding, hum and noise that these basses have stock also contributed to their lack of popularity. If you went into a music store to try one, and it either didn't work or was noisey, you'd put it aside and quickly demo the next bass. But I saw them as an opportunity to bring a good bass design up to a pro-level bass quality, and with these modifications I have not been disappointed.
Thanks for taking the time to read my Jaguar Bass page------- and keep on rockin'. ;-)
Not being extremely thrilled with the Jag's kinda loose, and 'boom/sizzle' stock preamp (treble and bass controls) I just replaced it by installing an EMG BTS system in it. The EMG's treble and bass controls have center detents (as a reference to flat), 4 selectable treble frequencies, a better bass boost/cut frequency, as well as a cleaner, more punchy circuit. (the fender circuit was just about all boost with hardly any cut).

I didn't want to route or modify the body in any way, so in order to use the jag's stock thumb wheels, I had to find and order some 50K linear pots with a shorter threaded mounting shaft that still had the center detent.. Mouser had them and they arrived in three days.
Here's a pic of the EMG pots:
Here's the new pot as compared to the EMG one.
(notice the threaded mount is about 1/2 as long):
I bent the 5 pin connector 90 degrees so it would fit underneath the switch in the upper control plate cavity.

Here's a pic of the new (bass control) pot wired to the EMG's main pcb:
Here's a pic of the new treble pot (left) and EMG treble pot mounted to it's pcb:
.........and here's a pic of the new treble pot wired to the pcb:
Finally, I used the old preamp's cavity under the pickguard to add another 9V battery in series to the original one, so the system runs on 18V for better performance and maximum headroom (as recommended by EMG for bass):

Well, I found out very quickly that first I had to reverse the outer wires on the new pots since the controls worked backwards (easy one minute fix).

Once i got them running the same way as the original controls, I gave it a listen. This preamp is TONS better than the stock one. It's still completely bypassable (with the switch on the upper control plate), but I actually prefer to always leave it on. In the center detents, the tone gets a tad brighter, and a very slight rise in gain (1 1/2-2db) occurs, which I suppose is due to the buffering. And when you roll the volume down, it's tone stays pretty much the same in any position (the highs don't roll off near as much as in the passive mode).

The DiMarzio ultrajazz bass pickups in this bass sound great and are extremely quiet. When the preamp is kicked in, there is no additional hum, but there is a slight amount of hiss added, which is normal for any preamp that is buffering/boosting the signal and frequencies, and it is much quieter than the Fender preamp that it replaced.

I have an EMG VMC (variable midrange control) on its way to me, and I'm going to experiment with replacing the jag's passive master tone with the EMG's mid control. It has a concentric pot (300hz-3Khz freq on the ring, and a center detent boost/cut on the upper) so I also ordered the Fender stacked knob kit that looks like a regular jazz bass non-stacked knob (not a conventional jazz bass stack knob) fo it.

After tweaking the new EMG  BTS preamp a little bit more, trying to get it to be as invisible as possible with the bass and treble controls in their center detents ( i.e. zero gain boost, or eq change)  I believe that I acheived it. In this bass, the preamp is after the (passive) master volume & tone controls, so rolling either one down has no effect on the hiss. The EMG BTS was a little brighter when switched in, so I added an .022uf cap to ground. Now there is absolutely NO difference in volume, and the hiss (at around 8-10Khz) was reduced by more than 75%. It still sounds transparent and can get too bright if I crank the treble (just as it was before), but this way, it sounds and feels much more natural. I was looking for no volume boost so that when on stage it wouldn't be too 'hyped' when clicked in, and for me, it is absolutely perfect this way, and I couldn't be happier with this modification.

I'm generally a passive bass guy, but after using my EMG JV/TBC jazz bass at the last gig, and loving it, I thought it might be cool to have treble, sweepable mids, and bass controls all onboard at least one of my Fender basses. I mean, the way I see it, i might as well take advantage of all the knobs and switches that they put on this thing.
I used very thick (3/32") 3M heavy duty clear double stick tape to mount the main pcb in the cavity, and the small one on the control plate. The thick tape is super strong and insulates the bottom of the pcb's from the shielded/painted cavity and the chrome control plate.