About SPL

Since 1983 SPL is developing audio gear for music, film, multimedia, hi-fi and broadcasting.
Experimenting and listening is more important to this brand than designing by the book. They create innovative audio products by pushing the envelope of both technology and design in search for the unique performance that sets SPL products apart from the main stream.

Milestones of the development

• the invention of the patented Vitalizer® sound optimization
• the invention of level-independent envelope processing, which is used in the Transient Designer products
• the development of the auto-dynamic de-esser with S-sound reduction by means of phase cancellation
• the first discrete 5.1 surround microphone system Atmos 5.1
• the development of the Car Vitalizer® App for iOs devices
• the development of the 120V operational amplifier
• the invention of the Phonitor Matrix for loudspeaker-equivalent listening and mixing via headphones

SERIES ONE - New Products

NUMBER ONE IN SOUND

For us the sound is always in the foreground. When it sounds good, we like to listen. To get such a sound, you need experience and technical finesse. We have incorporated both into the Series One.

The Revolution

in the headphone amplifier is the Phonitor Matrix, with adjustable crossfeed, thanks to which you can create mixes with headphones that sound the same on speakers.

The Phonitor Matrix in its largest expansion stage has three parameters: Crossfeed, Speaker Angle and Center Level.

In the Series One, the center level is preset to -1 dB and the speaker angle to 30°. These are the most commonly used values. The crossfeed function determines the so-called interaural level difference. The intensity of the crossfeed is fully variable. At the beginning of the control path the crossfeed circuit is not in the audio path. Dialing the control in switches on the crossfeed circuit via relay (hysteresis circuit). The audio signal therefore does not pass through the crossfeed stage if this is not desired.

Best fit

If the active speakers or the power amplifier are very sensitive the playback may already be fairly loud when the Volume control is in the first third of its control range. By activating the -10 dB dip switch the output level is lowered to accommodate for a wider usable range of the Volume control.

With the Rec 1+2 dip switch both line inputs are mixed together and can be recorded via USB.

Power Supply

Good sound always starts with the power supply. This is where you lay the foundation for the performance of the entire device.

Although we “only” supply a 12 V plug-in power supply unit, the secondary power supply inside generates a voltage level of +/-17 Volts for the analog audio sections with which professional levels of up to +22.5 dB can be achieved!

An elaborate low-drop operating voltage regulation provides more “juice” and regulates cleanly even when maximum operating voltages are reached.

The Series One delivers full power when used with the included 1.5 A power supply. Only use the 12 V plug-in power supply unit within the scope of delivery. The ON-switch puts the Series One into operation.

Marc One

The Monitor And Recording Controller

with innovative features and a 32-bit AD/DA converter. A monitor controller with which you can also record. And both in impressive sound quality.

Speakers & Subwoofer

You can listen to your production via two switchable pairs of speakers. A subwoofer is also switched on and off with speaker pair A. In the middle position of the switch, the speakers are switched off, which is convenient because you don’t have to turn the volume control back.

Monitor

You can adjust the volume levels at lightning speed with the Monitor knob. In the middle, all input signals are equally loud. To the left, the analog stereo inputs get louder and the USB input signal gets quieter. Turning from the center to the right does the opposite. So you can quickly and intuitively set the right volume levels.

Line Inputs & USB

Two analog stereo inputs and one digital USB input can be connected to the Marc One. The DAW (Digital Audio Workstation) is preferably connected via USB. Other players like CD player, mixer, mic preamp, synthesizer or an analog tape machine / tape deck can be connected to the analog line inputs.

32-bit AD/DA Converter

The converter chipset is from AKM’s premium Velvet Sound® series. The AK5552 is used as the analog-to-digital converter and the AK4490 as the digital-to-analog converter. Both the AD and DA converters offer 32-bit processing. The Velvet Sound® technology makes the finest details audible thanks to its low-distortion architecture. Sampling frequencies up to 768 kHz PCM (16 times CD resolution) as well as the playback of DSD (via DoP – DSD over PCM) up to a resolution of DSD4 or DSD256 (11.2 MHz) are supported. This qualifies the Marc One for the highest resolution audio recording and playback currently available. The USB connection is Class Compliant. This means that all Mac computers and iOS devices like iPads and iPhones can use the full performance bandwidth of the AD/DA converter without driver installation. iOS devices need the Camera adapter. For Windows, a driver is only needed if higher sample rates are desired. The driver is available for download at the bottom of this page.

Line Out

The Line Out carries the mix between the Line Inputs and USB playback and is controlled by the Monitor knob. The level is unity gain, thus independent of the volume control. So the Marc One can be looped between devices without “losing” an output. For example, if several people should listen in via headphones, headphone amplifiers can be connected to the Line Out. But you can also record the signal analog or send it to a mixer for further processing.

Three Monitoring Modes

are offered by the Marc One. In the middle is the default setting “Stereo”. To check the mono compatibility set the switch to “Mono”. The special feature is the channel swap function.

L/R > R/L

reverses the stereo image. L/R becomes R/L. This is important and extremely time-saving when you are searching your sound library for samples in video dubbing that should match a scene with direction of movement. If the direction is not correct, you usually will have to import the sample into the DAW to swap channels before you can hear and judge if the sample with reversed direction fits to the picture. With the L/R > R/L function this is no longer necessary. You can now simply swap the direction of movement while pre-listening samples in the library.

The Headphone Power Amp

Poor sound over headphones?

Not enough juice?

Not here. Marc One delivers a rich headphone sound and it can get really loud.

The output stage of the headphone amplifier is designed as a push-pull amplifier in class AB mode. The bipolar transistors share the amplification of the positive and negative half-waves, which produces a higher gain and a higher output voltage than in Class A operation, where only one transistor amplifies both half-waves. The output stage transistors are thermally coupled and thus run particularly coherently, which contributes to a consistent and stable sound image. The power supply has a buffer circuit with low source resistance, ensuring generous current reserves even when driving low-impedance headphones.

Control One

The Monitor Controller

with innovative features, developed for fast workflow and impressive sound quality.

Speakers & Subwoofer

You can listen to your production via two switchable pairs of speakers. A subwoofer is also switched on and off with speaker pair A. In the middle position of the switch, the speakers are switched off, which is convenient because you don’t have to turn the volume control back.

Two Stereo Inputs

Two analog stereo inputs can be connected to the Control One for sources such as a DA converter, CD player, mixing console, mic preamp, synthesizer or analog tape machine/tape deck, which can also be listened to mixed together (1+2).

Line Out

The selected input signal is output unchanged at the Line Out. This allows the Control One to be looped between devices without “losing” an output.

If, for example, several people are to listen in via headphones, a headphone amplifier can simply be connected to the Line Out. You can also record the signal analog or send it to a mixer for further processing.

Three Monitoring Modes

are offered by the Control One. In the middle is the default setting “Stereo”. To check the mono compatibility set the switch to “Mono”. The special feature is the channel swap function.

L/R > R/L

reverses the stereo image. L/R becomes R/L. This is important and extremely time-saving when you are searching your sound library for samples in video dubbing that should match a scene with direction of movement. If the direction is not correct, you usually will have to import the sample into the DAW to swap channels before you can hear and judge if the sample with reversed direction fits to the picture. With the L/R > R/L function this is no longer necessary. You can now simply swap the direction of movement while pre-listening samples in the library.

The Headphone Power Amp

Poor sound over headphones?

Not enough juice?

Not here. Marc One delivers a rich headphone sound and it can get really loud.

The output stage of the headphone amplifier is designed as a push-pull amplifier in class AB mode. The bipolar transistors share the amplification of the positive and negative half-waves, which produces a higher gain and a higher output voltage than in Class A operation, where only one transistor amplifies both half-waves. The output stage transistors are thermally coupled and thus run particularly coherently, which contributes to a consistent and stable sound image. The power supply has a buffer circuit with low source resistance, ensuring generous current reserves even when driving low-impedance headphones.

Phonitor One

The Audiophile Headphone Amplifier

with innovative Phonitor Matrix and outstanding sound quality.

The Design Of The Amplification Stages

The Preamplifier Stage

Two Burr-Brown OPA 2134 SoundPlus™ operational amplifiers provide the pre-amplification. These are specially designed for audiophile circuits and are characterized by extremely low noise and minimal distortion of only 0.00008%.

Thanks to a true FET stage, the OPA 2134 achieves a slew rate of 20V/µs, making it a high-speed operational amplifier. This has an immediate positive effect on the liveliness of the playback.

In addition, low capacitance film capacitors are installed in the signal path as bypass capacitors of the coupling capacitors, which ensures a more precise transmission of the high-frequency signal components. The excellent Panasonic ‘Electric Double Layer’ gold electrolytic capacitors are used as coupling capacitors. They offer the highest storage capacity of all capacitor technologies.

The Power Amplifier

The output stage of the headphone amplifier is designed as a push-pull amplifier in class AB mode. The bipolar transistors share the amplification of the positive and negative half-waves, which produces a higher gain and a higher output voltage than in Class A operation, where only one transistor amplifies both half-waves.

The output stage transistors are thermally coupled and thus run particularly coherently, which contributes to a consistent and stable sound image. The power supply has a buffer circuit with low source resistance, ensuring generous current reserves even when operating low-impedance headphones.

Two Line Inputs

Two analog stereo inputs can be connected to Phonitor One.

Sources such as a DA-converter, CD-player, mixer, synthesizer or an analog tape machine/tape deck can be connected to the analog line inputs either balanced (TRS jacks) or unbalanced (RCA).

If you want to connect your computer, tablet or phone directly, check out Phonitor One d with USB input and a state-of-the-art 32-bit DA-converter.

Phonitor One d

The Audiophile Headphone Amplifier

with innovative Phonitor Matrix, 32-bit DA-converter and outstanding sound quality.

The Design Of The Amplification Stages

The Preamplifier Stage

Two Burr-Brown OPA 2134 SoundPlus™ operational amplifiers provide the pre-amplification. These are specially designed for audiophile circuits and are characterized by extremely low noise and minimal distortion of only 0.00008%.

Thanks to a true FET stage, the OPA 2134 achieves a slew rate of 20V/µs, making it a high-speed operational amplifier. This has an immediate positive effect on the liveliness of the playback.

In addition, low capacitance film capacitors are installed in the signal path as bypass capacitors of the coupling capacitors, which ensures a more precise transmission of the high-frequency signal components. The excellent Panasonic ‘Electric Double Layer’ gold electrolytic capacitors are used as coupling capacitors. They offer the highest storage capacity of all capacitor technologies.

The Power Amplifier

The output stage of the headphone amplifier is designed as a push-pull amplifier in class AB mode. The bipolar transistors share the amplification of the positive and negative half-waves, which produces a higher gain and a higher output voltage than in Class A operation, where only one transistor amplifies both half-waves.

The output stage transistors are thermally coupled and thus run particularly coherently, which contributes to a consistent and stable sound image. The power supply has a buffer circuit with low source resistance, ensuring generous current reserves even when operating low-impedance headphones.

Three Stereo Inputs

Two analog stereo inputs and one digital USB input can be connected to Phonitor One d. The computer, tablet or phone are preferably connected via USB.

Other players such as a CD player, mixer, synthesizer or an analog tape machine / tape deck can be connected to the analog line inputs either balanced (TRS jacks) or unbalanced (RCA).

32-bit DA-Converter

The converter chip used is the Premium AK4490, a new generation of premium 32-bit DACs equipped with AKM’s Velvet Sound®. This technology makes the finest details audible thanks to its low-distortion architecture.

It supports sampling frequencies up to 768kHz PCM (16x CD resolution) and DSD (Direct Stream Digital) playback up to DSD4 or DSD256 (11.2 MHz) resolution.

This qualifies the Phonitor One d for the currently highest resolution audio playback.

The USB connection is Class Compliant. This means that all Mac computers and iOS devices like iPads and iPhones can use the full performance bandwidth of the DA-converter without driver installation.

iOS devices require the camera adapter. For Windows a driver is required, which you can download at the bottom of this page.

Line Out

The selected input signal is output unchanged at the line out. This allows Phonitor One d to be looped between devices without “losing” an output connection.

If, for example, several people are to listen in via headphones, a headphone amplifier can simply be connected to the Line Out.

But you can also record the signal analog or send it to a mixer for further processing.

Thus, the Phonitor One d can also be used as a state-of-the-art DA-converter, which recommends it for a series of other tasks.