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Fender JP 90 club?

#301
Hey there. Just picked up my Second JP-90 bass. The first one was a weird aqua blue color, picked up from Ed Roman Guitars in Las Vegas circa 2005. I traded it for my first synthesizer and found out the new owner quickly traded it to the local music store for weed money. I was pissed. It has always been 'the one that got away'. I got this one locally for $600. You think you see everything while you are evaluating a guitar for purchase, but missed the fact that this one was missing the outside saddle screw on the G string. Luckily for me I had bought a bridge off a JP-90 for abt $15 on reverb for another project and just gave it the quick swap. Much happier and less of a hassle than bickering at the music shop.

I have a few questions:

Has anyone pulled off a nut replacement with an off the shelf nut? There seems to be some discrepancies between Fenders spec sheets and TB members own accounts of their own nut width. I assume such nut would be flat bottom as it looks like a slab board but ive seen readings anywhere from 38mm to 41mm. Is there a variance over the years of production? In short, link me if youve had success with a particular nut replacement. Mine has the dreaded A string buzz.

Can someone post a picture of their cavity/wiring? Im suspecting someone modded mine as the tone cap looks suspect and someone may have gone so far as to attempt a treble bleed mod on mine. Also the screw holes for the pickguard are stripped, dead giveaway. Also the ground from the 3rd leg of the tone pot is knocked loose from its joint on the ground bus-bar.

Any luck jamming a Fender stealth string retainer under the ferrule of the LBSchaller tuning keys? Ive already ordered one but didnt notice this was not the type of tuners with the screw lug built in. Oh well. Ill find a use for it.
20210301_185218.jpg


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#303
The nut can be replaced with a GraphTech PT-1215-00. I bought one, but was able to save my original bone nut with the baking soda and super glue trick. The G string slot was a little deep so some backfill and re-filing have done fine. There are different sizes, but the 1215-00 is the right size for this particular J-bass.

On the A-string, I looked at the same device, but have been able to satisfactorily wind at least 3-turns around the peg to eliminate the A-string buzz in the nut slot. An easy way to do this is to pull the new string taught to the post, then trim it to the same length as 4 string posts on the headstock. That will get you 3 or slightly more full wraps. Also, wind them down towards the headstock.

That looks like the original capacitor to me and circuit to me. It was a green polyester cap on mine. I did re-wire mine though with new Bourns 95 pots and did the "grease bucket" tone (hate the name) mod. The solder blob on the third leg is a sign someone diddled with it. I still have my originals as removed.

Weakest point in the bass are the crap electronics on the pickguard. Those pots crackled not long after I bought the bass brand new in the 90's.

The bridge is just standard off-the-shelf Fender stamped bridge. Parts are pretty easy to come by. Mine got a black BadAss-II bridge the day I brought it home from the store long ago.
 
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#304
larrysb said:
The nut can be replaced with a GraphTech PT-1215-00. I bought one, but was able to save my original bone nut with the baking soda and super glue trick. The G string slot was a little deep so some backfill and re-filing have done fine. There are different sizes, but the 1215-00 is the right size for this particular J-bass.

On the A-string, I looked at the same device, but have been able to satisfactorily wind at least 3-turns around the peg to eliminate the A-string buzz in the nut slot. An easy way to do this is to pull the new string taught to the post, then trim it to the same length as 4 string posts on the headstock. That will get you 3 or slightly more full wraps. Also, wind them down towards the headstock.

That looks like the original capacitor to me and circuit to me. It was a green polyester cap on mine. I did re-wire mine though with new Bourns 95 pots and did the "grease bucket" tone (hate the name) mod. The solder blob on the third leg is a sign someone diddled with it. I still have my originals as removed.

Weakest point in the bass are the crap electronics on the pickguard. Those pots crackled not long after I bought the bass brand new in the 90's.

The bridge is just standard off-the-shelf Fender stamped bridge. Parts are pretty easy to come by. Mine got a black BadAss-II bridge the day I brought it home from the store long ago.
Click to expand...
most helpful! thanks!
 
#305
Not strictly JP-90 related, but my new Fender USA Geddy Lee Jazz Bass came in today. I have to say, I'm super impressed so far with it. The neck is much meatier than the JP-90, even more than I expected. But so far, finding it quite comfortable. I'll probably post some comparisons if y'all don't mind.
 
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#307
Here we go! I got a little more playing time in after work. Unfortunately I sliced my right middle finger in the kitchen over the weekend. Nothing serious, but I can't pluck the strings with it properly until it heals up. The tone is great on the Geddy. Hard to make a comparison because I put half-round strings on the JP-90 a couple of weeks ago and I'm not using the stock pickups.

Still a virgin bass with all the plastic wrap on it. My second brand new bass ever.

IMG_2066 (1).jpeg
 
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#308
About those stock JP-90 pickups...

I promised to write this up a year ago. So, if you're curious about the stock pickups on the JP-90, all will be revealed...

The pickups appear to be standard J and P type from the outside. The J pickup has "neck" spacing. That's because on the JP-90, the bridge pickup is 3.0" from the nominal bridge saddle point. On the regular Jazz bass, the bridge pickup is 2.25 from the saddles. Though, that has has moved around through the years.

Also, you'll note from the picture, these pickups are ceramic magnet types. The classic Fender pickups have alnico magnets, which are the pole pieces. These have soft-iron pole pieces, and all the magnetic energy comes from the two bar magnets on the bottom. The magnets also make the pickup thicker, so if you replace with standard alnico, you'll also need new, thicker suspension foam. The coils are also potted (embedded) in epoxy which glues the pickup, cover and magnets together as a unit. Typically, you can easily remove the cover from standard Fender pickups.

This is typically the pickup construction found in imported Fender, like later Japan models, standard Mexico models and low-cost Squier from various countries. Nothing wrong with this type of pickup. They usually have a bit warmer and woolier sound. The magnetic field is not as focused as with the alnico poles. My personal preference is for the classic alnico p'ups. I swapped for a Fender Yosemite JP set, mostly because they were on sale. So far, they've been good.

The windings measure roughly 11k and 7k.

IMG_1501.jpeg
IMG_1502.jpeg
IMG_1503.jpeg
 
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#309
So, I've had this crazy idea rolling around my head for a while. I really have enjoyed my JP-90 all this years since it was new. I think the idea and the design is great. The execution came up a bit shy in my opinion, since it was built to a price point. Fender set out to make the least expensive instrument that they could stamp "made in USA" on. I have loved mine since new, inspite of its quirks and flaws.

The idea: Design and order the fantasy Fender Custom Shop JP-90.

What I like:

1. light weight.
2. good balance.
3. simplicity.
4. fun to play, especially on stage.
5. slimmed down and restyled jazz-bass body.
6. the quirky 'end of new-wave era' design aesthetic, even the totally weird "comic-bubble" pickguard.
7. Truss adjustment at the headstock (early JP90 have heel adjustment, later have headstock)

What could stand improvement:

1. Electronics upgrades, mostly the quality of pots, jack and switch.
2. materials - woods, plastics, just use better stuff
3. workmanship - mine was not drilled properly and pickups was all cattywampus.
3. fitments - high mass bridge, lightweight tuning pegs, something to pull down the A-string, hardware.
4. A custom selected or wound pickup set, perhaps a noiseless J-pickup and P pickup that really pairs well with the J.
5. Shielding the electronic cavity.

Stuff I'd consider:

1. a thumb rest.
2. color schemes to really play up the quirky design
3. quarter-sawn neck (especially if skinny like the original)
4. Slightly increased neck profile
5. Maybe some options on the tone circuit or tricks on the electronics.
6. Perhaps moving the bridge pickup closer to the bridge. (2.25" on j-bass, 3" on ours)
7. Maybe a 9.5" radius fretboard vs. the 7.25" radius.

Having played my new Geddy Lee USA Jazz a few days now, I remembered what I like about J-bass and JP-pickup basses. The J-bass has a quadrillion range of sounds since you can blend the controls as you wish.

I think the switch/V/T actually works better for the JP pickups. A lot of times, I just want that pure grunty P-bass sound. I could be convinced otherwise.

I'm not sure about active electronics. I've had and liked them, but there's something good about simple passive pickups.
 
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#310
I'd be really curious whether the FCS would do a JP90. The main issue I've got with the instrument is the use of poplar, which is an understandable tradeoff, but I wouldn't mind a few more ounces for alder.

The good news is that most of the upgrades you mention can be done by the hobbyist. I stuck a Badass on mine, but mostly because I rest my hand there and I had one lying around. I'd love a late 80s color scheme, with graphics on the PG... Maybe something you'd find on a Trapper Keeper, or on a Maui and Sons shirt.
 
Last edited:
#311
larrysb said:
What I like:
...
6. the quirky 'end of new-wave era' design aesthetic, even the totally weird "comic-bubble" pickguard.
Click to expand...
I tried to find some of this Formica design for a pickguard (my JP-90 is red), but I couldn’t locate a sample of the required size. The pattern mimics the pickguard shape really well. It would have been really cool.

upload_2021-3-13_17-30-30.jpeg


larrysb said:
Stuff I'd consider:

1. a thumb rest.
Click to expand...
Here’s mine (thanks, LEGO), plus the pickguard I ended up with:

upload_2021-3-13_17-42-24.jpeg
 
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#315
larrysb said:
So, I've had this crazy idea rolling around my head for a while. I really have enjoyed my JP-90 all this years since it was new. I think the idea and the design is great. The execution came up a bit shy in my opinion, since it was built to a price point. Fender set out to make the least expensive instrument that they could stamp "made in USA" on. I have loved mine since new, inspite of its quirks and flaws.

The idea: Design and order the fantasy Fender Custom Shop JP-90.

What I like:

1. light weight.
2. good balance.
3. simplicity.
4. fun to play, especially on stage.
5. slimmed down and restyled jazz-bass body.
6. the quirky 'end of new-wave era' design aesthetic, even the totally weird "comic-bubble" pickguard.
7. Truss adjustment at the headstock (early JP90 have heel adjustment, later have headstock)

What could stand improvement:

1. Electronics upgrades, mostly the quality of pots, jack and switch.
2. materials - woods, plastics, just use better stuff
3. workmanship - mine was not drilled properly and pickups was all cattywampus.
3. fitments - high mass bridge, lightweight tuning pegs, something to pull down the A-string, hardware.
4. A custom selected or wound pickup set, perhaps a noiseless J-pickup and P pickup that really pairs well with the J.
5. Shielding the electronic cavity.

Stuff I'd consider:

1. a thumb rest.
2. color schemes to really play up the quirky design
3. quarter-sawn neck (especially if skinny like the original)
4. Slightly increased neck profile
5. Maybe some options on the tone circuit or tricks on the electronics.
6. Perhaps moving the bridge pickup closer to the bridge. (2.25" on j-bass, 3" on ours)
7. Maybe a 9.5" radius fretboard vs. the 7.25" radius.

Having played my new Geddy Lee USA Jazz a few days now, I remembered what I like about J-bass and JP-pickup basses. The J-bass has a quadrillion range of sounds since you can blend the controls as you wish.

I think the switch/V/T actually works better for the JP pickups. A lot of times, I just want that pure grunty P-bass sound. I could be convinced otherwise.

I'm not sure about active electronics. I've had and liked them, but there's something good about simple passive pickups.
Click to expand...

Regarding the pickguard, definitely make it three ply instead of one ply. I've seen a number of JP-90s where the pg cracked near the output jack. A one ply is way too weak. The shape itself is strangely endearing after some time, definitely unique. When I had my JP90, I shielded the cavity, it definitely helped.
 
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