SPL Diamond DA Converter User Manual
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Welcome
Thank you for choosing the SPL Diamond. The Diamond is a perfect DAC and preamplifier for users who exclusively play music from digital sources. It offers connectivity for five digital sources and an external word clock. The superior VOLTAIR technology, combined with the premium DAC including DLP120, allows digital players to experience soundscapes never encountered before. The analog volume control ensures high-resolution dynamics even at low volumes.
Getting started
Read thoroughly and follow the instructions as well as the security advices of the Quickstart which is enclosed in the scope of delivery! You can also download the Quickstart [here].
By pressing the [Index] button you get to the table of contents.
By pressing the [Front View] button you get to the front view of the unit.
By pressing the [Rear View] button you get to the rear view of the unit.
By pressing the [Previous] button you get to the previous content.
Front view
The front panel features the following controls and indicators:
- 1 Stand-by: Power on/off button.
- 2 Display: Shows selected source, sampling rate, or error messages.
- 3 Word-Clock-Schalter: Switch for selecting the word clock source (internal or external).
- 4 Lautstärkeregler (Volume knob): Controls the analog output volume.
- 5 Quellenauswahl (Source switch): Selects the digital input source.
- 6 Power LED: Indicates the power status.
Input indicators include USB, Coax 1, Word, Coax 2, Optic 1, Source, Optic 2, and AES. Technology indicators show 32BIT, PCM768, DSD4, and DLP120. The unit is described as a "Digital to Analog Converter" with "VOLTAIR 120V DC Audio Rail" technology.
Rear view
The rear panel provides connections and settings:
- 7 Digital Audio Inputs: Includes AES/EBU (XLR), Coax 1, USB, Optic 2, Word In, Optic 1, Coax 2.
- 8 DIP-Schalter: Switches for configuring output settings.
- 9 Mains Voltage: Selector for 115 V AC / 230 V AC.
- 10 Mains Switch: Power switch.
- 11 Analog Outputs (RCA fixed output): Unbalanced analog outputs.
- 12 Analog Outputs (XLR fixed output): Balanced analog outputs.
- 13 Word-Clock-Eingang: Input for external word clock signals.
Safety warnings are present: CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN (ATTENTION RISQUE DE CHOC ÉLECTRIQUE NE PAS OUVRIR).
Power specifications include mains voltage (switchable), fuses (T 1A for 115V, T 0.5A for 230V), and power consumption (max. 30 W).
VOLTAIR – 120V Technology
VOLTAIR is the designation for SPL's 120V Technology used in the Professional Fidelity series. Audio signals are processed with an unequalled +/-60V DC, which is twice the voltage of discrete operational amplifiers and four times that of semiconductor operational amplifiers. This technology achieves outstanding technical and sonic performance, particularly in dynamic range, headroom, and the reproduction of fine details, delivering a relaxed and natural sound experience.
SPL's 120V Technology refers to the internal audio processing voltage (+/- 60V DC) and should not be confused with the external mains voltage (e.g., 115V or 230V AC).
Comparisons
These diagrams illustrate how VOLTAIR Technology compares to other circuits, focusing on operating level and maximum level, which impact dynamic range, distortion limit, and signal-to-noise ratio.
Operating Voltage
A bar chart compares operating voltages: "+/- 15 Volt" versus "+/- 60 Volt". The "+/- 60 Volt" level is significantly higher.
Dynamic Range
A bar chart shows dynamic range in dB: "OPA 134@30V" measures 124.2 dB, while "SPL-OP@120V" measures 141.4 dB.
Max. Audio Level
A bar chart displays the maximum audio level in dBu: "OPA 134@30V" reaches 21.5 dBu, and "SPL-OP@120V" reaches 33.2 dBu.
THD&N (Total Harmonic Distortion + Noise)
A bar chart shows THD&N in dBu: "TL071@30V" is -106 dB, and "SPL-OP@120V" is -114.2 dB.
Note: 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 12 dB higher values for maximum level and dynamic range compared to common components, representing over 130% improvement in THD measurements.
Operation
Volume
Control the volume of the analog outputs using the volume knob (4). The RCA and XLR outputs can also be set to a fixed level (Unity Gain) via the DIP switches on the rear panel (see page 15).
Source Selection
Use the Source switch (5) to select the input source: USB, Coax 1, Coax 2, Optic 1, Optic 2, or AES.
Display
After selecting a source, the display (2) initially shows the source name for two seconds (e.g., USB, COAX1, OPT1, AES). Subsequently, it displays additional information based on the clock source (selected source or external word clock). Error messages appear if no signal or word clock is detected.
Display after two seconds – Word Clock: Source
The display shows the first letter of the selected source along with the detected sampling rate (e.g., U384 for USB at 384 kHz, C192 for Coax at 192 kHz).
| Digital source | Sample rate PCM (kHz) | Sample rate DSD (n * 44.1 kHz) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 44.1 | 48 | 88.2 | 96 | 176.4 | 192 | 352.8 | 384 | 705.6 | 768 | 64 x | 128 x | 256 x | |
| USB | U 44 | U 48 | U 88 | U 96 | U176 | U192 | U352 | U384 | U706 | U768 | DSD1 | DSD2 | DSD4 |
| Optical | O 44 | O 48 | O 88 | O 96 | - | - | - | - | - | - | - | - | - |
| Coax | C 44 | C 48 | C 88 | C 96 | C176 | C192 | - | - | - | - | - | - | - |
| AES/EBU | A 44 | A 48 | A 88 | A 96 | A176 | A192 | - | - | - | - | - | - | - |
If there is no signal at the selected source, the first letter of the source will blink (e.g., U for USB, C for Coax 1 or Coax 2, O for Optic 1 or Optic 2, or A for AES).
Display after two seconds – Word Clock: Word
When an external word clock is used, the display shows the letter "W" along with the sampling rate (e.g., W 96).
The following error displays are possible:
| Digital source | No Signal at selected source | Word samplerate and samplerate of selected source do not match | No Word signal |
|---|---|---|---|
| Optical | O (flashes alternately with W) | SR~W (flashes) | W |
| Coax | C (flashes alternately with W) | SR~W (flashes) | W |
| AES/EBU | A (flashes alternately with W) | SR~W (flashes) | W |
The USB source does not support external Word Clock.
Word Clock
If an external Word Clock is connected, set the Word Clock switch (3) to the "Word" position. When set to the "Source" position, the Diamond derives its clock from the selected digital source.
DIP Switches
The DIP switches (8) on the rear of the unit allow for the following settings:
- DIP switch 1: OFF = The level of the RCA analog output is adjusted with the volume control.
- DIP switch 1: ON = The level of the RCA analog output is fixed (Unity Gain).
- DIP switch 2: OFF = The level of the XLR analog output is adjusted with the volume control.
- DIP switch 2: ON = The level of the XLR analog output is fixed (Unity Gain).
Diagram shows: 1 ON: RCA fixed output, 2 ON: XLR fixed output.
Specifications
Inputs and Outputs
Digital inputs
- 6 digital inputs
- AES/EBU (XLR), balanced
- 2 x Coaxial SPDIF (RCA)
- 2 x Optical TOSLINK (F06)
- USB (B)
- 0 dBfs = 15 dBu
- Converter Chip: AK4490-Velvet Sound
Sample rates 32 Bit
- Encoded PCM (kHz): 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384, 705.6, 768
- DSD: DSD1 (DSD64), DSD2 (DSD128), DSD4 (DSD256)
Outputs
- 2 analog stereo outputs
- Neutrik XLR, balanced, Pin 2 = (+)
- RCA, unbalanced
- Impedance: 75 ohms (balanced)
- Max. output level: 32.5 dBu
Measurements
- Frequency range: 10 Hz – 300 kHz (-3 dB)
- Crosstalk at 1 kHz: -108 dB
- THD: 0.001 % (0 dBu, 1 kHz)
- Noise (A-weighted): -102.3 dB
- Dynamic range: 134.8 dB
Internal Voltage
- Audio: +/- 60 V
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
- Standby power consumption: < 0.3 W
Diagram shows a standard IEC power connector with N (Neutral), L (Live), and Ground symbols.
Dimensions (incl. feet)
- 278 mm W x 57 mm H x 300 mm D
- 10.95 in W x 2.24 in H x 11.81 in D
Weight
- 3.15 kg; 6.94 lbs (unit only)
- 5.35 kg; 11.79 lbs (shipping)
Reference: 0 dBu = 0.775V. All specifications are subject to change without notice.
Important Notes
Version: 1.0 – 11/2022
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 product delivery by SPL electronics GmbH. The design and circuitry are under continuous development and improvement; technical specifications are subject to change.
© 2022 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 in this manual are the trademarks or registered trademarks of their respective companies.
Declaration of CE Conformity
[CE Conformity Mark] The construction of this unit is in compliance with the standards and regulations of the European Community.
