Flexible digital input options include AES XLR 3-pin, two S/PDIF RCA coaxial jacks, two optical TOSLINK S/PDIF jacks, and a USB-B port, which provides the highest sample rates, while balanced XLR and unbalanced RCA outputs are provided stereo analog connection to your speakers or mixer. The innovative onboard VOLTAiR technology and shielded toroidal transformer delivers superior rail voltage for the internal circuitry, ensuring that the Diamond provides the highest quality audio experience possible by vastly improving dynamic range, distortion, SNR, and maximum gain levels.

Everything Under Control
The volume is adjusted with a solid, milled aluminum, rotary knob. The Alps RK27 Big Blue potentiometer gives a pleasant spoon in the honey rotary feel.
Six Stereo Sources
Up to six digital stereo sources can be connected to the Diamond, making this DAC/preamp an ideal heart for any digital audio system. Diamond offers both a stereo USB and AES input as well as two optical and coaxial stereo inputs. The selected input is also shown in the dot matrix LED display.
Via USB, both PCM audio and DSD audio can be converted. PCM audio is received in S/PDIF format, both coaxial (RCA), optical (TOSLINK F06) and balanced (AES/EBU).

Always in Time
Diamond can not only synchronize to the clock integrated in the digitally fed source signal. As a specialty for digital players, Diamond offers a word clock input. The source of the clock signal can be selected via the clock switch.

Well Informed
The DAC automatically picks up the sampling rate and resolution of the digital playback source, regardless of whether a streamer, computer, CD player, or an external word clock is connected. The detected sampling rate and the selected clock source are shown in the dot matrix LED display. For example, U768 is an acronym for a clock signal in the USB stream with a sampling rate of 768 kHz.

All Variable or Slave Thru
Diamond provides two stereo output pairs for connecting power amplifiers or active loudspeakers. One pair of outputs utilizes XLR 3-pin connectors while the other uses RCA outputs. Both have the same output signal, which is controlled by the volume control on the front panel.

The volume control for the RCA outputs can be switched out of the signal path via DIP switch on the back of the device. For example, a headphone amplifier with its own volume control can be connected to one of the outputs.

The DAC
The highly acclaimed AKM AK4490 Velvet Sound premium DAC chip is used as the converter chip in the digital-to-analog converter, which thanks to its architecture reproduces the finest sound details. It converts PCM audio with a resolution of 32 bits and a sampling rate of up to 768 kHz, which is equivalent to 16 times CD resolution. Direct Stream Digital is also supported up to resolution of DSD4 or DSD256.

The DLP120 (Dual Low-Pass)
Every signal that is passed from a DAC chip into the analog world must be filtered be filtered by a low-pass filter. Two of them are implemented in the DLP120: One for PCM audio and one for DSD audio, since different roll-off frequencies are required. In contrast to all other DACs in the world, the low-pass filters here are built using VOLTAiR technology, which provides a plus in dynamics, headroom, and sound.

Sounds Great
With all devices of the Professional Fidelity series, we develop not only according to plan, but also by ear. Many important components are installed on the circuit boards using Through-hole technology. This way, SPL can ensure that they use the best sounding components.

VOLTAiR: 120V Rail Technology
VOLTAiR is the synonym for SPL's 120V Rail Technology within the Professional Fidelity series. The audio signals are processed with an unequalled ±60V DC, which corresponds to twice that of discrete operational amplifiers and four-times that of semiconductor operational amplifiers.

VOLTAiR Technology reaches outstanding technical and sonic performances, especially in terms of dynamic range, headroom, and in reproducing the finest details and delivering a totally relaxed sounding audio experience. Music sounds absolutely natural.

SPL Diamond Specs
Form Factor Tabletop
Number of Headphone Channels Single Channel
Digital Chipset DAC:
1 x AKM AK4490 Velvet Sound
Analog Circuitry Low-Pass Filter IC:
2 x DLP120
EQ None
Display 1 x Monochrome LCD
Connectivity
Analog Audio I/O 2 x XLR 3-Pin Balanced Master Output (1 Stereo Pair, Rear Panel)
2 x RCA Coaxial Unbalanced Line Output (1 Stereo Pair, Rear Panel)
Digital Audio I/O 1 x XLR 3-Pin AES3 Input
2 x RCA Coaxial S/PDIF Input
2 x TOSLINK Optical S/PDIF Input
USB 1 x USB-B (Digital Input)
Wireless Connectivity None
Performance
Frequency Response 10 Hz to 300 kHz
Maximum Output Level 32.5 dBu
Dynamic Range 135 dB
Impedance 75 Ohms
THD+N 0.001001% (0 dBu, at 10 Hz to 22 kHz)
Noise -102.3 dBu (A-Weighted)
Crosstalk -108 dBu (A-Weighted)
Digital Audio
Sample Rates TOSLINK Optical S/PDIF Inputs:
44.1 / 48 / 88.2 / 96 / 176.4 / 192 kHz (PCM)
RCA Coaxial S/PDIF Inputs:
44.1 / 48 / 88.2 / 96 / 176.4 / 192 kHz (PCM)
XLR AES3 Input:
44.1 / 48 / 88.2 / 96 / 176.4 / 192 kHz (PCM)
44.1 / 48 / 88.2 / 96 / 176.4 / 192 / 352.8 / 384 / 705.6 / 768 kHz (PCM)
2.8 / 5.6 / 11.2 kHz (DSD)
Compatibility
Mobile App Compatible No
*As of February, 2023: Check with manufacturer for the most up-to-date compatibility
Mobile Device Compatibility None
Power
Power Requirements AC Input
Rail Voltage Preamp:
±120 V (High Power)
AC Input Power User Selectable:
115 to 230 VAC, 50 / 60 Hz (T 1 A)
Ground Lift No
AC/DC Power Adapter None
Power Consumption 40 VA (Maximum)
Physical
Dimensions 118.1 x 109.4 x 22.4" / 300 x 278 x 57 cm
Weight 6.9 lb / 3.1 kg