The Ultra features a special wiring system using 4 Lace Sensor pickups. The pickguard comes shielded from the factory. One thing all Ultras did have, and that was the 4 Lace Sensor and the 3-way mini-switch used for the two red Lace pickup referred to as a Dually in the bridge position. Most came with a Blue/Silver'Red Dually Lace Pickup configuration, but there were a few early models that had a Gold Lace in the middle position. When you pop the hood on some of the Ultras you often find things like Fender's Custom Shop logo on the inside of the pickguard, as some of these were used on the CS Neck-set Strats which often used Lace Sensors. There will sometimes find the word "Ultra" stamped inside the neck socket.
NECK pickup is a Blue Lace Sensor which has an increased output with the warmer 50's humbucking sound. It delivers a Gibson P-90 type sound.
MIDDLE pickup is a Silver Lace Sensor which delivers a fat 70's single coil sound with increased output and more midrange. Great for those out of phase sound when combined with the neck or bridge pickups. Some ealry Ultras came with a Gold Lace in the middle position.
BRIDGE pickup is a Dually Red Lace Sensor which is two Red Lace Sensors placed side by side. The Red Lace are the hottest output of the Sensor Series, and gives a fat, punchy humbucking output. Sometime you pop open these and find interesting things inside like finding out the pickguard came from Fender's Custom Shop. Some have Ultra stamped in the neck socket!
Very few people know the secret to the Ultra wiring schematics, which produces a unique variation in sound. Here is how the switch works:
Position #1: The bridge pickup using a 3-way mini-switch. This alone gives several variations, which are really cool. Here is what the "mini-switch" does to the Dually bridge pickup (and remember too, that these settings can be mixed with the other pickups). Up) activates the front bridge pickup which creates a out of phase hollow sound, which then can be mixed with the middle pickups with the 5-way Super Switch. Middle) has the bridge pickups in series creating a hot humbucker sound. Down) activates the back pickup on the bridge to give a single coil sound which mimics the tone of a Telecaster bridge pickup. The distance of the pickups from the bridge creates different tones.
Position #2: The bridge and the middle pickups mixed together, which can get a multitude of Strat out-of-phase tones because of the mini-switch and the TBX tone control.
Position #3: Here is where we part from standard Strat wiring. Instead of just running the middle pickup, this position mixes the neck pickup with the bridge pickup like on any 2 pickup guitars, such as a Telecaster. Again, with the mini-switch you can shape the color of the sound. Full, rich rhythm sounds. And both tone controls are also combined in this position too.
Position #4: Is the neck and the middle combined in an out-of-phase vintage Strat tone.
Position #5: Is totally vintage Strat with just the neck pickup and the middle tone control.
As on all the Plus Series, the Ultra comes with Fender's TBX tone system. I explain the the TBX tone control here in great detail (When you click on that link, just scroll down!) The bottom tone control is a stacked set of potentiometers that cuts either treble or bass instead of the standard style of tone that cuts treble only. T (treble) B (bass) X (Cut) thus TBX). When you turn this knob, you can feel a halfway point which is tone neutral. This tone control gives the bridge and middle pickups a unique variety of sounds