Overview
The XR Spectra pickups are low-impedance (Lo-Z) pickups with a uniform frequency response from 20Hz to 20kHz. The XR Spectra pickup is engineered to capture the signal induced by the string with no added coloration.
Traditional high-impedance (Hi-Z) pickups have their own baked-in character. You will have to replace the pickup to get a different tone — characterized by the pickup’s frequency response and defined by its resonant frequency, which typically starts to fall off around 2-6 kHz. The XR Spectra pickups, on the other hand, allow you to change the pickup’s tone anytime using post EQs.
The XR Spectra pickup can be active (powered with a preamp), or passive (no preamp, no batteries). In passive mode, it has an output comparable to passive under-wound pickups. In active mode, it has an output comparable to an EMG81 pickup.
For detailed information, see the XR Spectra User’s Manual.
Actual measured frequency responses of various pickups vis-à-vis the XR Spectra pickup (blue line near the top).
Features
- Active or passive configuration
- Low-impedance (Lo-Z)
- Low string-pull Neodymium magnets
- 30kHz resonant frequency
- Uniform frequency response to 20kHz
- Humbucking dual rails
- Can be combined in pairs for PAF “humbucker” form-factor
- 60mm, 70mm and 82mm standard widths
- Optional Tone Block: Buffered second-order resonant filter
XR Spectra bottom view with expansive Lo-Z passive connectivity and configurations for one or more pickups in parallel or series.
Lo-Z
The XR Spectra is a dual-coil low-impedance (Lo-Z) pickup with 1000 turns AWG 38 magnet wire per coil and a magnetic structure with low permeability, utilizing Neodymium magnets that do not influence the inductance of the coils and do not induce eddy currents that degrade the frequency response. The pickup has an expansive frequency response well above 20kHz.
- 1000 Turns
- 300Ω DCR (for 60mm version)
- 76mH
- AWG38 self-bonding magnet wire
- 2mm Type 430 ferritic stainless steel rails
- Neodymium magnets
Conventional pickups require significantly many turns of wire to deliver a signal output sufficient to drive guitar amplifiers. The higher the number of turns, the stronger the output. But this comes at the expense of coloration of the sound, primarily determined by the pickup’s inductance, which forms a low-pass filter that attenuates frequencies above its cutoff frequency. As you increase the number of turns in the coil, you also increase the inductance, and the cutoff frequency is inversely proportional to the inductance. The higher the inductance, the darker the tone.
Why Lo-Z?
But I do not have bat ears. Why will I want a pickup with a frequency range that extends beyond 20kHz? People do not want “high fidelity” pickups. They want the tones they hear on a record. And that is definitely not “high fidelity”.
A full-range pickup with uniform frequency response is like a blank white canvas. Traditional high-impedance (Hi-Z) pickups have their own baked-in character. You will have to replace the pickup to get a different tone — characterized by the pickup’s frequency response and defined by its resonant frequency, which typically starts to fall off around 2-6 kHz. The XR Spectra pickups, on the other hand, allow you to change the pickup’s tone anytime using EQs.
Beyond emulating other pickups, you are free to explore the wide unfiltered open frequency space. You get to play with the full 20Hz to 20kHz (and beyond, if you do have bat ears). You do the filtering, not the pickup.
The XR Sound
We used the original XR pickup as our sonic baseline throughout the development of the XR-Spectra. In this section, we compare the sound of the XR to that of the XR Spectra v2. The sound of full-range XRs is then compared to three common high-Z pickups: the Gibson BurstBucker, DiMarzio Injector Neck, and DiMarzio Evolution Neck.
Note: Please use a decent set of headphones or speakers, or ideally, a good reference monitor.
The following audio clips were recorded dry, straight to an audio interface and a DAW. There are no effects or EQ. The samples were recorded with the pickup selector in the neck position. The strings are picked at the 24th fret (or where the 24th fret on the Les Paul and Strat should be). Every audio clip has been normalized to -0.1dB.
The spectral fingerprints of the original XR and the XR Spectra v2 are nearly identical, though there are subtle differences, particularly in higher frequencies above 8kHz. This is because the magnetic structures are different: the original XR is a side-winder, whereas the XR Spectra v2 is a dual-rail. Minor differences can be compensated for with judicious use of EQ:
The key point here is that all the harmonics are present, and each XR Spectra v2 pickup is guaranteed to have the same frequency response. This consistency is critical in establishing a baseline, or reference point, before dialing in the desired EQ.
Here are audio clips from the Les Paul Studio (Gibson BurstBucker), a Fender Stratocaster (DiMarzio Injector Neck), and an Ibanez JEM7V (DiMarzio Evolution Neck) for comparison. As expected, there is a 12dB/octave cutoff somewhere between 2 and 6 kHz.
Is It For You?
- If you play clean, this is the perfect pickup for you! This is probably the cleanest sounding pickup ever.
- If you play exclusively with distortion and high gain, you are likely better off using high impedance pickups.
- If you frequently switch from dirty to clean, and everything in between, then the XR Spectra, together with the Tone Block, is well suited for you as an extremely versatile pickup.
The Tone Block is a small passive second-order (two-pole) resonant RLC filter with variable frequency and Q (resonance). It is specifically designed as post filter for the XR Spectra pickups, active mode, giving you the freedom to change each pickup’s character on the fly (more information below).
What People Say
Follow this link and see what people say about the XR pickups. Here are some of the quotes:
Hi! Pre-production is ready for my solo project Simple Music for Difficult People! I’m used to hi-fi pickup (I’m a long time user of Q-Tuner pickups) but the XRs sounds way better to me, and they perfectly fit in my style.
We are overwhelmed by the sound of this amazing pickup combination by Cycfi Research Inc. The XR is an active humbucker at the size of a single coil pickup. The sound is clean and transparent, almost acoustic.
— Touch Guitars www.touchguitars.com
Best pickup I’ve ever used in any guitar. It does not sound sterile in the slightest; it sounds full, reproducing the entire frequency range of the instrument from top to bottom with no dips anywhere in the frequency range. Since installing the XRs in my custom Jaguar, my passive guitars have remained untouched and I don’t see that changing in the future.
— Dylan Reznick
Audio Samples
Here’s another test video clip demonstrating the original XR in various positions and combinations, courtesy of Fabio Mittino:
If you want more audio demos, the original Cycfi XR sound clips showcase the sonic quality of the Cycfi XR extended response pickups.
Active Mode
The XR-Spectra pickup can be configured as active by connecting the output of the pickup to the preamplifier. The preamplifier accepts its input from the output of the XR-Spectra pickup and raises the signal level by 5x (the preamplifier gain).
The XR-Spectra preamplifier is a low-power, single op-amp differential amplifier with a gain of 5 (14dB). The preamplifier consumes only 125 µA. It is modular, and reusable. It can be connected anywhere in the signal chain; right after each pickup, after the switch, etc. It can be placed inside a stomp box to keep the instrument purely passive (no batteries).
Tone Block
The Tone Block (optional) is a small buffered second-order (two-pole) resonant RLC filter with variable frequency and Q (resonance). It is specifically designed as post filter for the XR Spectra pickups, giving you the freedom to change each pickup’s character on the fly. The Tone Block can be inserted after the preamplifier.
This passive second-order filter consists of an inductor, multiple capacitors and resistors in a parallel power of 2 configuration, switched using two miniature rotary hex switches, giving you 16 positions for frequency and another 16 positions for Q. The second-order filter provides a 12dB/octave (40dB/decade) roll-off, which is exactly the response of a traditional high-impedance passive pickup that the Tone Block is meant to emulate.
The Tone Block allows you to dial in the characteristics of virtually any pickup.
Documentation
For detailed information, see the XR Spectra User’s Manual.
Dimensions
Here are some technical drawings for reference. Click the links to the PDF files.