SPL Phonitor x

Welcome

Thank you for choosing the Phonitor x. The Phonitor x is the ultimate headphone amplifier, offering connections for headphones operated both balanced and unbalanced. With up to 3.7 W output power, it delivers impressive performance.

The Phonitor x is not just a headphone amplifier but also an excellent preamplifier capable of driving power amplifiers or active speakers.

VOLTAIR technology, also known as SPL 120V Rail Technology within the Professional Fidelity series, makes the Phonitor x an outstanding device in terms of dynamic range, signal-to-noise ratio, and headroom, delivering an exceptional sound experience with serenity, transparency, and realness.

Getting Started

Read thoroughly and follow the instructions and security advice in the enclosed Quickstart. You can also download the Quickstart here.

Navigation buttons:

• I: Table of Contents
• F: Front View
• R: Rear View
• B: Bottom View
• ← (Back arrow): Previous Content

Front View

The front panel features the following controls and indicators:

• 1 Standby: Power standby button.
• 2 VU Meters: Two meters displaying input levels, calibrated from -20 dB to +5 dB.
• 3 Phonitor Matrix On/Off: Activates or deactivates the Phonitor Matrix.
• 4 Crossfeed: Rotary control for adjusting interaural level difference.
• 5 Angle: Rotary control for adjusting interaural time difference, related to speaker placement (markings: 22°, 30°, 40°, 55°).
• 6 Laterality: Rotary control for adjusting sound perception differences between ears.
• 7 Volume: Main volume control.
• 8 Analog Source: Button to select between Analog inputs (XLR/RCA).
• 9 Digital Source: Button to select between Digital inputs (USB/Optical/Coaxial).
• 10 Mode Switch: Selects audio signal mode (Stereo, Stereo with Laterality, Mono).
• 11 Output/Mute Switch: Selects output (Loudspeakers or Headphones) or Mute.
• 12 Balanced Headphone: 4-pin XLR headphone output.
• 13 Standard Headphone: 6.35mm TRS headphone output.

Rear View

The rear panel provides connections and configuration options:

• 13 Mains Switch: Power switch.
• 14 Mains Voltage: Switchable mains voltage selector (115V/230V).
• 15 Analog Audio Inputs: Balanced XLR and unbalanced RCA inputs.
• 16 Digital Audio Inputs (Optional): USB, Optical TOSLINK, and Coaxial SPDIF inputs.
• 17 IR PGM Volume: Button for IR remote control programming.
• 18 AMP CTL: Connector for remote power control of connected power amplifiers.
• 19 Audio Outputs: Balanced XLR and unbalanced RCA line outputs.

Voltage Selection: To change the mains voltage, remove the fuse holder, exchange fuses, flip the holder, and reinstall it.

Fuses: 230V AC: T 500 mA L 250 V; 115V AC: T 1 A L 250 V.

DIP Switches (Bottom Side):

• 1 ON: HP Out +22dB
• 2 ON: HP Out +12dB
• 3 ON: VU 0 = +10dB
• 4 ON: XLR Direct Out
• 5 ON: RCA Direct Out
• 6 ON: AMP CTL power off when listening to Headphone.

Wiring:

• XLRs: Balanced, Pin 2 = Hot (+). For unbalanced operation, bridge Pin 3 to GND.
• RCAs: Unbalanced, Tip = Hot (+).

Bottom View

The bottom panel houses the DIP switches for configuration.

VOLTAIR – 120V Rail Technology

VOLTAIR is the synonym for SPL's 120V Rail Technology within the Professional Fidelity series. Audio signals are processed with an unequalled +/-60V DC, which is twice that of discrete operational amplifiers and four times that of semiconductor operational amplifiers.

VOLTAIR Technology achieves outstanding technical and sonic performances, particularly in dynamic range and headroom, and sonically in reproducing fine details, delivering a relaxed audio experience where music sounds natural.

Comparisons

These diagrams illustrate how VOLTAIR Technology compares to other circuits. The direct relation between operating level and maximum level is crucial for classification; a higher operating level allows a higher maximum level, positively impacting dynamic range, distortion limit, and signal-to-noise ratio.

Operating Voltage Comparison: A bar chart shows operating voltages for circuits using +/- 15 Volt, +/- 18 Volt, and +/- 60 Volt.

Dynamic Range Comparison: A bar chart compares the dynamic range (in dB) of OPA 134@30V (124.2 dB), OPA 134@36V (129.1 dB), and SPL-OP@120V (141.4 dB).

Max. Audio Level Comparison: A bar chart shows maximum audio levels (in dBu) for OPA 134@30V (21.5 dBu), OPA 134@36V (22.5 dBu), and SPL-OP@120V (33.2 dBu).

THD&N Comparison: A bar chart shows Total Harmonic Distortion plus Noise (THD&N) for TL071@30V (-106 dBu), OPA 134@36V (-111.7 dBu), and SPL-OP@120V (-114.2 dBu).

Note on dB Scales: dB scales are exponential. A 3 dB increase doubles acoustic power, +6 dB doubles sound pressure level, and +10 dB doubles perceived loudness. VOLTAIR Technology offers approximately 10 dB higher performance in maximum level and dynamic range compared to common components.

THD measurements show a difference of over 3 dB compared to OPA134 at 36V, translating to more than 50% improvement in sound pressure level. The typical operating level for audio equipment is +/- 15 volts.

Phonitor Matrix

Basics of Stereo Listening

When listening to speakers, sound from the right is perceived by both the right (red line) and left (green line) ears. This perception involves time delay and level differences, with the sound arriving later, quieter, and with a reduced frequency range at the opposite ear. This applies similarly to sound from the left speaker.

Stereo Listening with a Traditional Headphone Preamplifier

Traditional headphone amplifiers often present the right signal only to the right ear and the left signal only to the left ear. This misses the delayed and quieter signal from the opposite side, creating an unnatural sound that can be stressful for the brain as it tries to locate the sound direction. This can also lead to an exaggerated stereo width, making instruments appear further outside than intended.

The Phonitor Matrix corrects these unnatural effects.

How Does the Phonitor Matrix Work?

The Phonitor Matrix creates a speaker-like listening experience on headphones by calculating time and level differences with specific frequency responses, accurately rendering speaker playback. By simulating loudspeaker placement, it allows the brain to correctly identify sound direction, providing a speaker-like experience.

Instruments appear in their intended stereo positions, minimizing hearing fatigue compared to traditional headphone amplifiers.

In Detail: Angle

An analog filter design creates interaural time and level differences for various speaker placements. This is controlled by the crossfeed and angle parameters.

The ANGLE switch adjusts the interaural time difference, which is related to speaker placement. Settings correspond to different speaker angles.

Crossfeed

Crossfeed defines the interaural level difference. The six crossfeed values approximate the influences of room size, reflection, and absorption characteristics.

The interaural level difference and interaural time difference are frequency-corrected because the head absorbs and reflects sound non-linearly.

Setting of Crossfeed and Angle

Both Crossfeed and Angle parameters define interaural level and time differences. To reproduce exact loudspeaker placement, first select the Angle parameter closest to your real speaker setup. Then, choose the recommended Crossfeed parameter (e.g., for Angle 30°, Crossfeed 3).

Factors like loudspeaker type, room acoustics, and individual perception influence stereo listening. The Phonitor x offers six switch positions to finely adjust Crossfeed for optimal speaker playback matching.

Table: Settings of Crossfeed and Angle

Adjustment of the Phonitor Matrix

Use the CROSSFEED switch (4) and the ANGLE switch (5) to adjust headphone playback to your room and loudspeaker setup.

• Play familiar audio material and listen in your usual environment.
• Toggle between headphones and loudspeakers using the OUTPUT switch (11).
• Set the ANGLE switch according to your loudspeaker placement (see page 14).
• Set the CROSSFEED switch to match your familiar loudspeaker-listening sound.
• Listen to instruments panned in the stereo field; they should appear in the same positions on headphones.

Matrix On/Off

Use the MATRIX switch (3) to activate or deactivate the Phonitor x's Matrix function. The Phonitor Matrix is available only for headphone outputs; the Speaker Outputs (19) are not affected by the matrix.

Source Selection

The Phonitor x serves as a preamplifier with up to five audio sources. It features two analog stereo inputs: XLR and RCA (15). With an optional DA converter, it supports USB, coaxial, and optical digital stereo inputs (16).

• Select an analog audio source using the SOURCE switch (8) for RCA or XLR.
• Select a digital audio source (USB, coaxial, optical) using the DIGITAL switch (9). Set the SOURCE switch to Digital.

Signals at the analog RCA input will be amplified from HiFi to studio level. Sources are equalized in level when switching between XLR and RCA, provided a studio signal is present at the XLR input.

Output Selection

Use the OUTPUT switch (11) to send an input signal to the selected output: Loudspeakers or headphones. In the Mute position, no signal passes to the outputs, and the VU meters illuminate red.

When set to the loudspeaker setting, the selected input signal passes through to both analog audio outputs (RCA and XLR).

Note: The standard headphone output (13) has priority over the balanced headphone output (12). No signal is sent to the balanced output if a headphone is plugged into the standard output.

⚠️ Warning: Never connect a mono jack cable to the standard headphone output (front panel stereo jack). Ensure the stereo jack is fully inserted, otherwise a short circuit might damage the headphone amplifier!

MODE Switch

Use the MODE switch (10) to select the audio signal mode: Stereo, Stereo with Laterality control, or Mono. In Mono mode, both stereo channels are summed, maintaining loudness by reducing each channel by 6 dB.

Laterality

Laterality refers to the deviation in sound perception between ears. The Laterality control (6) compensates for perceived volume differences that may arise from hearing impairments. Unlike conventional balance controls, it attenuates one channel while increasing the other by the same amount (e.g., +2.25 dB for left, -2.25 dB for right). This control offers finer resolution and a narrower range than standard balance controls.

Set the MODE switch to LATERALITY to control laterality.

VU Meters

The VU meters (2) display input levels for the selected source, ranging from -20 dB to +5 dB (0 dB corresponds to +4 dBu).

Sensitivity can be lowered by 10 dB via DIP switches, allowing meters to register up to +15 dB input level.

The VU meters feature ballistics that ensure optimal visual perception, with time calibration meeting BBC requirements. The rise time to 0 dB is approximately 300 ms.

If the VU meters remain lit red even when unmuted, the protection circuit has activated, disconnecting the output connectors from the amplifier to protect headphones. Contact your local dealer for service.

AMP CTL (Amplifier Control)

If you own an SPL Performer s800, you can connect it to the Phonitor x's AMP CTL (18) using a mono mini-jack cable. This allows both units to be switched into and out of standby together. A 3.5 mm mono mini-jack cable is required.

The Phonitor x offers two outputs (A and B) for connecting two Performer s800 units in bridge mode or bi-wiring applications.

Set DIP switch 6 to ON to switch the Performer s800 into standby when the output selection is set to Headphone.

IR Remote Control

The volume potentiometer can be remotely controlled using any infrared (IR) remote control. The Phonitor x learns your remote, eliminating the need for a universal remote. You can assign Volume up/down functions to unused buttons on your existing remote (e.g., a CD player remote).

• During learning, set the OUTPUT switch (11) to Mute; the VU meters will light up red.
• Press the PGM IR VOLUME button (17) on the rear until the actuation point is noted; the Power LED will light up brighter.
• Point your remote at the VU meters (2) and press the button for volume down. The Power LED flashes once per push. Repeat until the LED flashes three times consecutively to complete programming.
• To program volume up, repeat the process. Learn mode ends after the second button is learned.

Note: Strong direct light (sunlight, halogen lamps, neon tubes, fluorescent tubes, terrariums, aquarium lights, large flat screens) may cause misoperation of remote control functions.

DIP Switches

The DIP switches (20) on the bottom of the unit allow for various settings:

Level Increase of the Headphone Output

Use DIP switches 1 and 2 to increase headphone output levels for power-hungry headphones:

• DIP switch 1: ON = Headphone output boosted by +22 dB.
• DIP switch 2: ON = Headphone output boosted by +12 dB.
• DIP switches 1 & 2: ON = Headphone output boosted by +24 dB.

Attenuate the Sensitivity of the VU Meters

Use DIP switch 3 to attenuate VU meter sensitivity by 10 dB. With the switch activated, a +15 dB input level can be displayed.

• DIP switch 3: ON = VU meter sensitivity attenuated by 10 dB. 0 dB on the VU meter then represents +10 dBu.

Slave Thru

Use DIP switches 4 and 5 to pass the chosen input directly to the outputs without volume control:

• DIP switch 4: ON = Input passes directly to the XLR output (Slave Thru).
• DIP switch 5: ON = Input passes directly to the RCA output (Slave Thru).

Standby of Connected Performer s800 Power Amp When Set to Headphone

Use DIP switch 6 to set connected units (Performer s800 power amp via AMP CTL) to standby to save power when the output selection is set to Headphone.

• DIP switch 6: ON = Units connected to AMP CTL are switched into standby.

Specifications

Inputs

XLR Inputs

• Neutrik XLR, balanced, Pin 2 = (+)
• Impedance: ca. 20 kohms
• CMR: -82 dBu (at 1 kHz)
• Max. Input level: +32.5 dBu

RCA Inputs

• Unbalanced
• Impedance: ca. 10 kohms
• Max. Input level: +32.5 dBu

Digital Inputs (Optional) / Sample Rates

• Coaxial SPDIF (RCA) - sample rates PCM (kHz): 44.1, 48, 88.2, 96, 176.4, 192
• Optical TOSLINK (F06) – sample rates PCM (kHz): 44.1, 48, 88.2, 96
• USB (B) – sample rates PCM (kHz): 44.1, 48, 88.2, 96, 176.4, 192

Outputs

Balanced Headphone Output

• Neutrik 4-pin XLR connector
• Pin wiring: 1 = L (+), 2 = L (-), 3 = R (+), 4 = R (-)
• Impedance: 0.36 ohms
• Damping factor: 180 @ 40 ohms
• Frequency range: 10 Hz to 300 kHz (-3 dB)
• Crosstalk at 1 kHz: -90 dB
• THD & N: 0.00091 % (at 0 dBu, 1 kHz, 100 kohms load)
• Noise (A-weighted): -98 dBu
• Dynamic range: 130.5 dB

Standard Headphone Output

⚠️ Warning: Never connect a mono jack cable to the standard headphone output (front panel stereo jack). Ensure the stereo jack is fully inserted, otherwise a short circuit might damage the headphone amplifier!

• 6.35 mm TRS connector
• Pin wiring: Tip = Left, ring = right, sleeve = GND
• Impedance: 0.18 ohm
• Attenuation factor: 180 @ 40 ohms
• Frequency range: 10 Hz to 300 kHz (-3 dB)
• Crosstalk at 1 kHz: -90 dB
• THD & N: 0.00091% (at 0 dBu, 1 kHz, 100 kohms load)
• Noise (A-weighted): -103 dB
• Dynamic range: 135.5 dB

Max. Output Power (at +30 dBu @ 1 kHz)

• 2 x 1 W at 600 Ohm impedance
• 2 x 2 W at 300 Ohm impedance
• 2x 3.7 W at 120 Ohm impedance
• 2x 2.9 W at 47 Ohm impedance
• 2x 2.7 W at 32 Ohm impedance

Line Outputs

• Neutrik XLR, balanced, Pin 2 = (+)
• RCA, unbalanced
• Frequency range: 4 Hz to 300 kHz (-3 dB)
• Crosstalk at 1 kHz: -106 dB
• THD & N: 0.00085 % (at 0 dBu, 1 kHz, 100 kohms load)
• Noise (A-weighted): -103.8 dB
• Dynamic range: 136.3 dB

Internal Operating Voltages

• Analog: +/- 60 V
• Digital: + 5 V and + 3.3 V (optional)

Power Supply

• Mains voltage (switchable): 230 V AC / 50 Hz or 115 V AC / 60 Hz
• Fuses: 230 V: T 500 mA; 115 V: T 1 A
• Power consumption: max 40 VA
• Stand-by power consumption: 0.7 W

Dimensions (incl. feet)

• (WxHxD) 10.94 x 3.94 x 12.99 in (278 x 100 x 330 mm)

Weight

• 9.48 lbs (4.3 kg), unit only
• 11.90 lbs (5.4 kg), shipping

Important Notes

Version 1.3 - 04/2017

Developer: Bastian Neu

This manual describes the product but offers no guarantee for specific characteristics or successful results. Unless stated otherwise, all information corresponds to the technical status at the time of delivery by SPL electronics GmbH. Design and circuitry are under continuous development and improvement; technical specifications are subject to change.

© 2017 SPL electronics GmbH. This document is the property of SPL and may not be copied or reproduced in any manner, in part or fully, without prior authorization by SPL. Sound Performance Lab (SPL) continuously strives to improve its products and reserves the right to modify the product described in this manual at any time without prior notice. SPL and the SPL Logo are registered trademarks of SPL electronics GmbH. All company names and product names are trademarks or registered trademarks of their respective companies.

Declaration of CE Conformity

The construction of this unit complies with the standards and regulations of the European Community.