Sound Performance Lab (SPL) continues to design extraordinary audio electronics, and forgetting to let the world know about it. The latest product to be dropped on the world by the company is a new digital to analog converter worthy of attention by those who need top audio playback quality from their digital sources. The new Diamond from SPL is a premium DAC and preamplifier with support for up to 32-bit/768kHz digital PCM and DSD256 audio decoding through the AKM AK4490 DAC and analog DLP120 dual low-pass filter chips.
In the best tradition of the products designed by SPL in Germany, the Diamond DAC will deliver the full sonic character of any digital source, adding the ability to select between the clock from the digital signal or a dedicated BNC word clock input – ideal for both studio and home high end audio.
Already using the latest AK4490 Velvet Sound DAC that Asahi Kasei Microdevices (AKM) started delivering in 2022, this SPL benefits from its superior 32-bit, 2 channel premium characteristics, with a superior signal-to-noise ratio of 120dB, which in this case is complemented by two DLP120 analog low-pass filter stages, which largely add the benefit of Wolfgang Neumann’s unique 120V VOLTAiR op amps and rail technology, ensuring exceptional dynamics and headroom. The reason for the two filters is that the analog output of the DAC requires different roll-off frequencies for PCM or for DSD audio, and this way each one benefits from its own optimized VOLTAiR filters.
Operation starts with a very simple front panel with a clear display that reveals the operational modes and sampling frequencies, and volume control adjusted with a solid, milled aluminum, rotary knob, which uses a Alps RK27 “Big Blue” potentiometer. And front and center, there is a clear position selector for up to 6 digital stereo sources, which can be connected to this Diamond DAC, making it one the most versatile and practical desktop options in the market.
Of course, the SPL Diamond offers each input through a stereo USB and AES input as well as two optical and coaxial stereo inputs. Via USB, both PCM audio and DSD audio can be converted. The PCM audio is received in S/PDIF format, both coaxial (RCA), optical (Toslink F06) and balanced (AES/EBU). The selected input is shown in the dot matrix LED display as USB, COA1, COA2, OPT1, OPT2 or AES. After approximately two seconds from the selection, the display shows the type of clock source and the detected sampling rate.
As a specialist in studio recording and top mastering equipment, SPL incorporated a word clock input option in this Diamond DAC. The source of the clock signal can be selected via the CLOCK switch, either to synchronize from the source signal or from the external Word Clock. The DAC automatically picks up the sampling rate and resolution of the digital playback source, no matter if a streamer, computer, CD player or an external word clock is connected.
As outputs, the Diamond DAC provides two stereo options for connecting power amplifiers or active loudspeakers, with XLR or RCA connectors. 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 allowing users to connect an external headphone amplifier with its own volume control.
A look at the board design that SPL offers always reveals a unique level of consistency and quality that is unique of a Germany-made product. As with all devices of SPL’s Professional Fidelity series, the most important components on the circuit boards are through-hole, allowing not only selecting the best sounding components, but also paving the way for potential upgrades.
SPL’s VOLTAiR technology and shielded toroidal transformer delivers superior rail voltage for the internal circuitry, ensuring that the Diamond DAC provides the highest possible dynamic range, and maximum gain levels with the best signal-to-noise ratios.
Nothing was forgotten in the design of this new DAC. To use the USB inputs, which do not require special drivers with macOS and iOS devices, SPL supplies dedicated drivers for Windows, starting with legacy versions 7/8.