Version 1.46
May 2015
Joel de Guzman
Cycfi Research, Inc.
Overview
Cycfi 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.
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 |
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| 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.
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)
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.
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.
À la carte Examples
Here are some more wiring possibilities using standard modular components.
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.
Cycfi XR Dual Active Pair (Double-Width)
This XR Dual Active Pair is comprised of two XR Active pickups in a double-width form factor. Each XR Active’s + (9V Power Supply), OUT (Preamplifier Output) and – (Ground) pins connect to the main switch. Click image to zoom-in for detail.
Note: The small molded triangle on the connector denotes the proper orientation when making connections.
Tip: This configuration is best suited for an H-H configuration that connects to the 5-way switch. One XR Dual Active Pair may be utilized for the neck (or bridge) pickup and another XR Quad Active pickup for the bridge (or neck) pickup for a total of three active pickups.
5-Way Switch
The switch is the main hub in your guitar through which all signals pass. The pickups, control potentiometers, output jack, power supply, and string ground all connect to the main switch via gold-plated 2.5mm headers connectors. Click image to zoom-in for detail.
Note: The small triangles in the image above denote the proper orientation when making connections via the header connectors. Each connector has a small triangle molded into the housing.
| Bridge | Connect to the Bridge Pickup. |
| Middle | Connect to the Middle Pickup.
Tip: For an H-H configuration, use an XR Dual Active Pair and connect the pickup closer to the bridge here. |
| Neck | Connect to the Neck Pickup.
Tip: For an H-H configuration, use an XR Dual Active Pair and connect the pickup farthest from the bridge here. |
| Power | Connect to a 9V battery or power supply. |
| Blend Control | Connect to an (optional) Blend Control. The blend control mixes the Neck and Bridge pickups, allowing for neck/bridge and neck/middle/bridge settings. Leave open when not in use. |
| Volume Control | Connect to the master Volume Control. The Volume Control (see below) may connect to a passive tone control. |
| EQ / Effects Insert | Connect to (optional) Eq or Effects. Use this to connect to the Resonant Filter, for example. Leave open when not in use. See bypass connections on the back of the switch below. |
| Output Jack | Connect to the output jack. |
5-Way Switch Back
Additional header connectors are provided at the back of the switch.
| “-” String Ground |
 Connect to string ground. Connect this to the supplied 2-Wire IDC Butt. Splice the end of the wire connected to the single-pin header with the end of the wire going to the string ground. Insert the bare wires inside wire-butt connector and crimp the connector with a pair of pliers until it snaps to make a firm connection (image at the right →). |
| PWR SW | Power Switch. Optionally connect to a SPST power switch. Use the supplied shunt when not in use. |
| BYP OUT FX |
EQ / Effects Bypass. Optionally connect to a SPDT bypass switch to toggle the EQ / Effects in and out. When not using a bypass switch, use a shunt:
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Volume Control
The master volume control utilizes a 25K audio taper (Bourns PDB181-GTR Series) potentiometer. The volume control includes a connector for an optional passive tone control. Without the tone control, simply leave the pins for it unconnected.
Note: The small molded triangle on the connector denotes the proper orientation when making connections.
Tone Control
The basic tone control is a simple passive low-pass filter using a 25K audio taper (Bourns PDB181-GTR Series) potentiometer in series with a 0.1μF capacitor to ground. It allows you to attenuate the high frequencies.
Note: The small molded triangle on the connector denotes the proper orientation when making connections.
Resonant Filter
Technically speaking, a pickup is an audio voltage source followed by a second-order lowpass filter. The tone (color) of the pickup is characterized by its cut-off frequency and its resonance contour — the so-called Quality factor or simply Q. The Resonant Filter allows you to dial in the characteristics of virtually any pickup with two high quality dual-ganged Bourns potentiometers.
Output Jack and 9V Connector
These should be self-explanatory, but for completeness:
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The negative supply from the battery is routed to the output jacks’s “ring” which shunts to ground when a mono plug is inserted. This connection is typical of active guitar electronics. Power is essentially disconnected when the guitar is unplugged. As previously mentioned, an SPST power switch may also be installed so that you don’t have to unplug the guitar to turn the power off.
Cables
Here are the cables included with the pickups and electronics:
- XR Active: Cable connects XR Active pickup to switch.
Important: The cable ends are not interchangeable. The cable ends will be labeled with “To Switch” and “To Pickup” for proper connection. The pickup end (“To Pickup”) is wired that way for compatibility with EMG pickups. - XR Passive: General purpose cable.
- 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 Coil to Coil: Connects passive coil to active coil in XR Quad.
- Output Jack: Connects output jack to switch.
- Ground Wire: Connects main ground to switch.
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