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Version 1.5
Feb 2016
Joel de Guzman
Cycfi Research, Inc.

Overview

xr_quadCycfi XR (Extended Response) series pickups are side-wound humbuckers, meaning the coils are oriented perpendicularly to those of most familiar designs. Each pickup has a pair of coils, one on either side of the row of pole-pieces. The coils are connected series/phase-opposing, like a typical humbucker. Utilizing low-impedance coils (Lo-Z 350Ω to 500Ω DCR), a full frequency response from 20Hz to 20kHz is achieved. While the pickups can be specified for any number of strings (6, 7, 8, etc.), the operating principles remain the same.

Previous Versions

Cycfi XR Series Datasheet v1.46

Specifications

XR6 XR7 XR8
D.C. Resistance per coil 379Ω  443Ω  509Ω
Coil Inductance 13.4mH 15.5mH 17.8mH
Flux Density (Sensor at 6mm from pole)
Baseline Stratocaster: 112.17 gauss
Baseline EMG 81: 67.17 gauss
86 gauss
Frequency Response 20Hz – 20kHz
Output Impedance 10kΩ
Voltage Output (automated; moderate picking)
Baseline Stratocaster (passive): 484mV peak-to-peak
Baseline EMG 81: 720mV peak-to-peak
Double Coil: 862mV peak-to-peak
Quad Coil: 634mV peak-to-peak
Supply Voltage 9V
Supply Current 684μA

Block Diagram

The Cycfi XR pickups are modular. There are only two basic configurations, XR Passive and XR Active. The only difference between the two is the inclusion of an integrated low-noise preamplifier in the XR Active pickups. These modular pickups can be connected in a multitude of ways.

Pickup-Diagrams

Pinouts

Ground
IN Preamplifier Input
C+ Coil A Tap
C- Coil B Tap
+ 9V Power Supply
OUT Preamplifier Output
Note: Multiple OUTs may be connected together for passive mixing.

Preamp Schematic

The circuit utilizes Toshiba 2SC3324 low-noise NPN transistors with an exceptional noise figure of 0.2dB (typical). The preamp configuration is a common-emitter amplifier with both emitter feedback and self-biasing collector feedback. The collector feedback ensures that the transistor is always biased in the active region regardless of variations in Beta. The second stage is a simple emitter-follower providing current gain and low output impedance.

(Click to view PDF)

XR_Preamp_Schematic

 

Factory Wiring

The modular design of the XR series pickups allows for various wiring configurations. A few versatile factory wiring options are provided to get you up and running quickly.  All cables and shunts are provided. Standard 2.5mm (0.1″) pitch header connectors are used. Because the pickups are modular, customized wiring beyond the factory options is straightforward.

Cycfi XR Dual Active (Single-Width)

The single-width Cycfi XR Active pickups come prewired with shunts from C- (Coil B Tap) to IN (Preamplifier Input) and C+ (Coil A Tap) to – (Ground). The + (9V Power Supply), OUT (Preamplifier Output) and – (Ground) pins connect to the main switch. Click image to zoom-in for detail. The diagram below shows how the coils are connected.

Note: The small molded triangle on the connector denotes the proper orientation when making connections.

Single-Width-Active-Diagram

Cycfi XR Quad Active (Double-Width)

The Cycfi XR Quad Active pickups are comprised of one XR Passive (see below) and one XR Active pickup in a double-width form factor. This configuration comes prewired with a connector that connects Coil A+B of the XR Passive in parallel with Coil A+B of the XR Active. The XR Active’s + (9V Power Supply), OUT (Preamplifier Output) and – (Ground) pins connect to the main switch. Click image to zoom-in for detail. The diagram below shows how the coils are connected.

Note: The small molded triangle on the connector denotes the proper orientation when making connections.

Tip:  A toggle switch may be utilized for a split-pickup (coil-tap) configuration, enabling both single-width and double-width settings. Both settings are hum-free.

Double-Width-Active-Diagram

Cycfi XR Passive (Single-Width)

This single-width XR Passive pickup is comprised of one passive humbucker. The passive pickup requires a separate preamplifier to boost the lower level signal from the coils to a suitable level. One or more coils may be connected, as any other passive pickup would be, prior to preamplification.

Note: The small molded triangle on the connector denotes the proper orientation when making connections.

Cycfi XR Quad Passive (Double-Width)

This XR Quad Passive pickup is comprised of two XR Passive pickups in a double-width form factor. The passive pickup requires a separate preamplifier to boost the lower level signal from the coils to a suitable level. One or more pickups may be connected, just like any other passive pickup, prior to preamplification.

Note: The small molded triangle on the connector denotes the proper orientation when making connections.

Cables

Here are the cables included with the pickups and electronics:

 

Pickup Cable connects XR active or passive pickup to switch.
Volume Control Connects volume control to switch.
Blend Control Connects blend control to switch.
Tone Control Connects tone control to volume control.
Resonant Filter Connects resonant filter to switch (two cables: one each for resonance and frequency control potentiometers)
XR Quad Connects passive coil to active coil in XR Quad.
Output Jack Connects output jack to switch.
Grounding Connects main ground to switch.

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