ChrsiP's JTL-1 "The Sphinx" - 1st Build

[chrisp]

How blue are you expecting it to be. .... Blue DT is usually a bit more like faded denim. Just trying to manage your expectations.

About this blue ....


This is just the stain coat, before the intensifying and finishing coats. I also use what I'd describe as a fast dabbing technique rather than the wipe or circular application shown in the vids. That seemed to bring out the colour and wood texture the best. I did two applications 24 hours apart.

That said, the back of the guitar will be a dark enamel spray blue. The DT blue has something to grip on the quilt maple veneer but doesn't really stain the smooth alder body or maple neck - Fretworn's 'faded denim' is a good description and I wanted a more intense colour for the headstock front and body rear. The neck itself will be a straight lacquer.

[Fretworn]

Hey! That veneer seems to have come up really well.

[chrisp]

Update - mostly been working on the neck finish. Back of neck has about 7 light lacquer coats then 2000 sandpaper, cutting polish and a final wax, it feels really smooth. I've left the stock end that fits into the neck pocket raw, and put the model name just above.





I conditioned the rosewood neck before applying my custom vinyl fretboard protectors, and have a blue enamel spray on the headstock front.



All that's really left to do is apply some clear top finish to that headstock front and install the locking tuners.

[wazkelly]

I really like the fret board design.

[chrisp]

Yeah! All finished, powered it up today, fixed intonation etc, sings like a bird. A reminder of the build ...

* A tele build into a Jazzmaster style body - Pitbull's JTL-1 with a quilt maple veneer
* Lindy Frahlin wired 4 way selector (neck, neck/bridge parallel, neck/bridge series, bridge)
* Fezz Parka tone wiring using a 15nf orange drop tone cap (sort of like a treble bleed with greater tone travel)
* Push/pull switch on volume to unload the pickups (wow! first time I've done this, it adds a whole new voice)
* 630V DC safety cap separates hardware from cable negative
* Australian hand wound Sliders Nocaster bridge pickup
* Q Pickups A3 in the neck

I really like the fret board design.

Thanks - I worked it up with a company called Neck Illusions, great crowd to do that sort of thing.

[Bakersdozen]

Can you please elaborate on this:
"630V DC safety cap separates hardware from cable negative"
Awesome build by the way mate!!

[chrisp]

Can you please elaborate on this:
"630V DC safety cap separates hardware from cable negative"!

Sure.

To begin, most guitar wiring confuses two separate circuits - ground and signal negative. The ground path includes things like the strings, bridge, control bodies and cavity shielding, and it's main purpose is to shield the signal from RF interference. The signal negative, on the other hand, is the reference 'zero volts' against which the pickup circuitry's voltage signal is measured. If everything goes right, you can simply connect these two paths together - and every time you see a potentiometer lug bent back and soldered to the pot body, that's an example of connecting the ground and sig neg paths.

In the vast majority of cases, connecting the two together doesn't matter. It all gets connected to ground in the amp via the guitar jack sleeve connector. But what if things go wrong ....

Some older tube amps can fail in a way that puts their HT (typically 300-400V DC) on the signal negative circuit, which in turn can make anything connected to that circuit dangerous. If your wiring connects ground and and signal negative, you've then got 400V on your bridge and strings, which might find its way to ground through you!

This mod is achieved by connecting all the ground circuit elements together, and all the signal neg elements (including the jack sleeve) together, but never having a direct connection between the two. Instead, you solder a 630V high value capacitor between the two paths. Caps will block DC voltage but pass AC voltages, so the RF interference (AC) will get shunted off to the amp ground but any DC volts finding their way onto the sig neg path won't get passed on to the bridge, strings or controls - it's likely that something else will blow first, rather than you getting fried.

The risk is not at all likely in modern amp design, but I do play with some older tube amps and its a really simple mod in any event. It has no effect on tone or volume, its really nothing more than a 20c bit of insurance against something that's not likely to happen. But in my view that's 20c well spent!



You can see the capacitor at the selector switch in this diagram of my build, but it can sit anywhere between the ground and sig neg paths that's convenient.

Awesome build by the way mate!!

Thanks. Your PRS is looking very pretty itself.

[Bakersdozen]

Thankyou for the detailed explanation, much appreciated.