P90 Blacktop Jazzmaster

Talk about modding or building your own guitar from scratch.
User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

P90 Blacktop Jazzmaster

Post by sirspens » Sat Jul 15, 2017 4:30 pm

A while back I parted together a Blacktop Jazzmaster with a body (unknown origin, but standard dimensions), loaded Warmoth pickguard and neck I got off of Reverb. The neck is from a current Squier Standard Stratocaster with the CBS headstock, which I prefer, for the headstock and the slim neck.

Image

After a few weeks of playing I decided I didn't really like the sound. The neck pickup didn't have that clean sparkle I have come to love in my VMJM and -- time to be honest with myself -- I just don't like humbuckers. I've spent years in denial, but they don't fit my style. I decided to do a bit of a take on the Blacktop by replacing the bridge pickup with something gnarly, but more my style... a P90.

I got a black cover JM101N for the neck pickup (the same neck pickup as the VMJM) and a P90 from a Fender Modern Player Jaguar. The pickguard from the first incarnation is from Warmoth, so I ordered another pickguard from Warmoth, in black, with a JM in the neck and P90 in the bridge. The electronics just got here from StewMac, the most important being the 1M pots.

Image

Image

So here is what it should look like when I'm done...

Image

My plan was to knock this out over the weekend and post it. But what's a guitar mod without a major complication, right?

Even though the original pickguard is Warmoth, and the new pickguard is Warmoth, guess what!!??!?

Image

The pickguard is just under a quarter inch longer than the original pickguard... ... ... Not going to be a quick mod.

Does anybody have any experience with Warmoth? I know they have all kinds of warnings that their pickguards are only for their bodies, but the previous pickguard was Warmoth and fit perfectly. This one doesn't fit at all. Not only is it too long, the neck pocket vs where the JM pickup route is located is different between the two pickguards. Should I assume this one was a mistake and ask for a replacement, or... I don't know.

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sun Jul 16, 2017 8:26 am

Did a bit of researching and problem solving last night.

First, I think I figured out what I did wrong with ordering the Warmoth pickguard. You can choose a bridge option, between a standard Jazzmaster bridge, a Hardtail/Tremolo bridge and a Floyd Tremolo. I didn't think much of it because it didn't seem to make a difference in the rendering of the pickup, but I left it on the default setting, for a standard Jazzmaster bridge. I probably should have picked the Hardtail/Tremolo option and it would have taken off the extra length.

I also have a solution to my situation, which may or may not work. Worst case scenario, I am ordering another pickguard.

Image

I am going to cut a notch into the pickguard to wrap around the bridge plate.

I also need to trim off a bit of wood to fit the P90, which I think I can accomplish with my "inverse conical sander" (drill press with conical sanding attachment). I will take a router to it if that doesn't work, but I am nervous to try to trim off that little wood with that much power.

Does anybody have any advice on cutting the pickguard with a clean finish? This small change doesn't exactly call for a template and router. I'll just be going for a vertical cut on this. I'm thinking a Dremel with a cutting disc for the straight part, and maybe a sanding drum to make a clean curved corner. Then come back with a razor blade and rough cloth to clean it up.

My other temptation on the pickguard is to use a Forstner bit on slow speed to cut the corner, then Dremel cut the straight part. But I'm worried about potential slippage of the bit, even at a good low speed.

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sun Jul 16, 2017 3:59 pm

I took a shot at cutting the pickguard.

Image

Now, if you look at the previous post, you will see that I mounted the bridge, with a spacer below, over the pickguard, then traced it, so I would know where to cut. And, when I was done cutting, that line was still left. But, somehow I still managed to screw it up. But I can still rescue this. I learned quite a bit just by doing it.

I did this by hand with a Dremel. First a cutting disc and then a sanding cylinder. Then I came back and cleaned it up a bit with a razor blade. It looked really good until I got it mounted to see how far off I was.

What I learned is that the Dremel is actually a fairly okay took to cut pickguards with. The sanding cylinder actually cut it easier than the cutting disc. What I need to do is get more control. I need to mount the Dremel in a basically router table fashion. I am going to look at Dremel bits and whatnot.

My plan is to recut this to make everything have the spacing as the top part with the curve more like the bottom part.

Also, with the use of my drill press sander and a chisel I got the body ready for the P90.

I have some time to get the pick guard right, because I need to paint the cavity with that black goop that I'm too tired to think of the name of at the moment. And that takes several days.

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sat Jul 22, 2017 10:18 pm

Today, in my continued quest to prove just how inept I am at even the simplest of tasks that involve working with my hands, I spent over an hour painstakingly setting up a routing template out of 1x2s to cut a squared and smooth notch into the pickguard to fit around the bridge, then used a router with a bearing bit to make the cut, cleaned up the corners a bit with a Dremel, still using the routing template.

And I really pulled it off. It took preparation and careful work, but I managed to create a gnarled and jaggedy -- and almost straight -- cutout for the bridge.

Image

So, having given up on any pretense of quality workmanship, and just wanting to play the guitar, I started wiring it up this afternoon. That could take a while, though. I'm especially bad at this whole "getting anything to stick to the back of a pot" soldering thing. I can literally spend hours at being unsuccessful at it.

Should have something playable soon.

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sat Nov 04, 2017 6:43 pm

It's been over three months, but i have some time to come back to this project. I did some research a month or two ago and found out that Warmoth does make a pickguard sized for the hardtail bridge, so I ordered one.

That just left getting things wired up. Which I started earlier this afternoon.

Image

Got it all together.

Image

And... it makes not a sound. So I spent the next couple hours examining my wiring, checking it against the diagram, checking my solders, redoing a couple of solders just to be sure. My soldering isn't the best, but it seems to work. Except, I couldn't find anything wrong. After several hours, I had to give up.

I guess I'll be spending tomorrow trying to track down where it stops making noise...

User avatar
HNB
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 10074
Joined: Tue May 10, 2011 7:55 am
Location: Puyallup, Washington
Contact:

Re: P90 Blacktop Jazzmaster

Post by HNB » Sat Nov 04, 2017 7:49 pm

I had thought the jack wires were reversed, but that looks ok.
Last edited by HNB on Sat Nov 04, 2017 7:54 pm, edited 1 time in total.
[Christopher]
God, grant me the serenity to accept the things I cannot change, Courage to change the things I can, And wisdom to know the difference.

User avatar
HNB
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 10074
Joined: Tue May 10, 2011 7:55 am
Location: Puyallup, Washington
Contact:

Re: P90 Blacktop Jazzmaster

Post by HNB » Sat Nov 04, 2017 7:54 pm

So I might be wrong, but looking at your toggle it looks like you have your grounds connected to the toggles output and the output wire connected to where the grounds go.

Either that or your pickup hots might be touching the ground with the switch. If you bend the tabs away from it a bit, that could help if that is the issue. I am guessing it is in the switch. :D
[Christopher]
God, grant me the serenity to accept the things I cannot change, Courage to change the things I can, And wisdom to know the difference.

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sat Nov 04, 2017 9:25 pm

HNB wrote:
Sat Nov 04, 2017 7:54 pm
Either that or your pickup hots might be touching the ground with the switch. If you bend the tabs away from it a bit, that could help if that is the issue. I am guessing it is in the switch. :D
That was it!

Thank you!

User avatar
timtam
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 1252
Joined: Sun Oct 22, 2017 2:42 am
Location: Melbourne

Re: P90 Blacktop Jazzmaster

Post by timtam » Sun Nov 05, 2017 1:58 am

While I don't possess the correct tools for doing professional pickguards either, I usually find that rough cutting first then finishing up the non-beveled straight edges manually with a flat file leaves everything nice and straight and at least 'looking' professional. It's only bevelled edges that I think probably do need the professional tools.
Timtam (noun): Iconic Australian multi-layered chocolate biscuit.

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sun Nov 05, 2017 8:27 am

Another testing session this morning, after quickly fixing the wiring problem last night.

Clean, it sounds pretty good. But with overdrive gain all the way up, the neck (Jazzmaster) pickup has a hum to it while the bridge (P90) has no hum to it. Which doesn't make any sense on its own, being that the P90 is hotter than the JM pickup. If anything, I would expect the P90 to have the hum because the ground wire on it was short and I had to extend it.

Then I thought maybe I had a cold joint at the ground to the volume knob from the JM pup. However, upon inspection, I twisted the ground wires from both pups together very tightly and soldered it. So, if one wasn't working, it would make sense for both of them not to work.

Maybe the JM pickup is more susceptible to hum than the P90?

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sat Feb 03, 2018 2:25 pm

Okay. I need some help!

I have inspected and tried to fix up the grounding on this guitar, but things have gotten worse.

I am getting a low growl from the P90 (switch in bridge position) and a high hum from the JM pickup (switch in neck position). When I touch any element (bridge, pots, switch, jack), the sound goes down by about half, but not fully. And nothing gets better in the middle switch position.

I checked all my solders, and they aren't pretty, but they all seem fine. I have tested connection between every element and I get reading that there is connection. Bridge to (back of) tone pot. Switch to tone pot. Volume pot to tone pot. Tone pot to jack. I went even further and tested from beginning to end... Bridge to jack. Switch to Jack. Bridge to switch. That one node on the volume pot to the back of the volume pot. I'm getting connectivity on everything I can test.

I don't know what I am doing wrong. I'm not good at this, but I've never had this kind of problem before.

I would appreciate any help anyone can provide. Thanks!

Image
Full quality image: http://cliftonstuckey.com/guitars/Vinta ... Wiring.jpg

User avatar
HNB
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 10074
Joined: Tue May 10, 2011 7:55 am
Location: Puyallup, Washington
Contact:

Re: P90 Blacktop Jazzmaster

Post by HNB » Sat Feb 03, 2018 4:14 pm

They are both single coil and will have some noise. Touching metal and having the noise get quieter is a sign your grounding is done correctly. If it got louder when touching the bridge or metal parts, then that would be a ground issue. To reduce the noise, you could shield the cavities and the back of the guard with copper tape or shielding paint. It helps greatly reduce the hum that comes with single coil pickups.
[Christopher]
God, grant me the serenity to accept the things I cannot change, Courage to change the things I can, And wisdom to know the difference.

User avatar
timtam
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 1252
Joined: Sun Oct 22, 2017 2:42 am
Location: Melbourne

Re: P90 Blacktop Jazzmaster

Post by timtam » Sat Feb 03, 2018 5:19 pm

One thing that may help at this stage is hearing what the pickups sound like independent of the guitar's other circuitry, to prove that they are both still working and see roughly what the final hum level should be. I have a short length of standard guitar cable with alligator clips on one end and an output jack on the other end for that purpose. Best done with the pickguard roughly in place so that so you get the benefit of the shielding.

You don't need to make that cable - some cheap test leads like those below will do. Use one from pickup hot to jack tip on a standard cable. Another goes from pickup ground to the jack shield. Run them out under the edge of the pickguard to the cable jack. Use short test leads and maybe twist them to limit any extra hum pick up.

Image
Timtam (noun): Iconic Australian multi-layered chocolate biscuit.

User avatar
sirspens
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 780
Joined: Sun Nov 08, 2015 8:26 pm
Location: Austin, Texas
Contact:

Re: P90 Blacktop Jazzmaster

Post by sirspens » Sat Feb 03, 2018 11:21 pm

timtam wrote:
Sat Feb 03, 2018 5:19 pm
One thing that may help at this stage is hearing what the pickups sound like independent of the guitar's other circuitry, to prove that they are both still working and see roughly what the final hum level should be...
I made something for that once!

Image

I'll give it a test.

However, I do want to be clear about this. The hum is louder than the pickups. That seems wrong to me. But I'll test out the individual pickups in the morning.

Also, I'll just go ahead and shield the cavity. I need to head back to the hardware store anyway.

Thanks HNB and timtam!

User avatar
Steadyriot.
PAT. # 2.972.923
PAT. # 2.972.923
Posts: 611
Joined: Wed Mar 09, 2011 2:16 pm
Location: The Netherlands

Re: P90 Blacktop Jazzmaster

Post by Steadyriot. » Sun Feb 04, 2018 11:22 am

Oh man, pardon my French but those solder joints look fucked.

For solder sticking to the back of the pot, sand the back with 400 grit to get rid of oxodization etc. This'll help. Also, what kind of iron are you using? Pots will suck up some heat and you'll need a little bit of oomph behind it to adhere the solder.
I solder on high heat (that's how we were tought in theaterschool). Just remember to be careful and to not touch anything with your soldering iron for longer than two to three seconds.

Touch the iron to the pot for about one or two seconds, then flow in your solder for another two to make a pool. Remove the tip and let it slightly cool. Pre-tin your wires, hold them to your now solidified pool of solder on the back of the pot and touch the pool, the tinned wire and just a little dab of fresh solder to make it all flow together. Remove the iron, hold the wire in place (try not to move it!) and wait for the solder to cool.

Eyelets work pretty much the same way, clean them with a little file or sandpaper, pre-tin your wires, feed them into the hole, touch the tip of your solder iron to the wire and your solder at the same time and let it fill the eyelet. Easy as pie!

Practice makes perfect when it comes to soldering; just spend some time soldering pots without them having to do anything to get a feel for this and you'll have it down in no-time!

Everything in the picture looks fixable so you'll have it up and running in no-time! No point in troubleshooting one problem when you're not certain any other thing wil work... Fix those joints and I bet your problem will be gone.

Good luck, you got this! Just keep your head cool and everything will turn out right.
"If someone duetted with a Bald Eagle, they could rule the Country charts from here to eternity." ~shadowplay

Post Reply