Piet's Tele Nashville mod

This page describes the modification that I made on my telecaster-style Jet JT-300 guitar.

Btw : there is a cool review of the JT-300 here on YouTube.

Highlights

added middle pickup for SSS pickup layout
10 pickup configurations :
- each pickup can be selected individually (3)
- each pair of pickups can be selected in parallel (3)
- all three pickups can be selected in parallel (1)
- both bridge and neck pickups can be put in series with the middle pickup (2)
- bridge and neck pickups in parallel can be put in series with the middle pickup (1)
tone control can be disabled for clearest tones

Adding the middle pickup

Some time ago, I replaced the three Roswell single coils in my Harley Benton ST-62MN VW with Fleor hot rails.

That left me with the three original single coils.

I decided to reuse the middle pickup for my JT-300.

The famous 'Nashville' telecaster acted as an inspiration.

The template for pick guard and pickup cavity

I made this template for both the pick guard and the pickup cavity.

The pick guard

Pasting the template, drilling a number of holes, filing, cutting, fitting, ...

Hacking the pickup cavity

I have no router and I din't want to invest in one for this project.

My template contains the centers of 5 25mm holes (using a Forstner drill bit).

The rest was done by chisel. Not the best looking job but no-one will ever see.

Fret job

While I was at it, I did a fret job. Sharp fret ends be gone.

The wiring

Pickup configurations

I designed the wiring diagram with simplicity in mind, only using one blade of a 5-way selector switch (typically sold as a 'strat' switch) and just three miniature SPDT rocker switches.

The wiring diagram shows the three single coil pickups on the left.

The hot wires coming from the pickups are indicated by a '+' ; the ground wires by a '-'.

Note that not all of these ground wires are connected directly to the ground.

Important : my bridge pickup had its ground wire connected to the base plate (which is effectively grounded through the three mounting bolts ; I had to cut that connection. (see pics further)

The hot wires are connected to the 5-way selector switch S1 in the usual manner.

When switches S2 and S3 are both in position 1 all of the pickup ground wires are effectively connected to the ground and the circuit behaves as a standard 3-pickup plus 5-way switch setup.

See also the table to the right.

When S3 is in position 2, the neck and bridge pickups are connected in parallel regardless of the position of the 5-way switch S1. This allows for combinations with neck and bridge in parallel en with all three pickups in parallel.

With S2 in position S2, the in-series magic happens. The middle pickup can be put in series with either the bridge or de neck pickup or even with both bridge and neck in parallel.

The table shows all possible combinations. The * symbol denotes parallel. The + symbol denotes in-series. Just like in calculus, * has precedence over +. In total there are 20 possible combinations with a total of 10 pickup configurations. (sorry about the duplicates)

IMPORTANT UPDATE : The combinations with the middle pickup in parallel or in series with other pickups sounded rather weak and thin. That was until I reversed the wires of the middle pickup. After this 180º phase shift, the guitar really sings. 😀

Tone control

The JT-300 comes standard with a A250kΩ tone pot and a 47nF capacitor.

I left these in place but I added a switch (S4) to disable the circuit altogether.

This gives the clearest tone one can get.

After all, a tone circuit does not add anything to the signal ; it only takes away the high frequencies.

Volume control

The JT-300 comes standard with a A250kΩ volume pot. I left it in place.

The control plate

I started by desoldering everything and removing all the components from the control plate. Then I drilled three holes between the pots for the toggle switches. No template here, just some calipers and a center punch. Then I continued by soldering everything together according to my wiring diagram.