Director MK 2

The SPL Director MK 2 is a digital-to-analogue preamplifier with connections for up to 10 stereo sources, including 6 analogue and 4 digital inputs. The analogue section provides 2 pairs of balanced XLR inputs and 4 standard inputs on gold-plated RCA connectors.

The 4 digital inputs accept PCM audio through coaxial Cinch, optical Toslink and balanced XLR AES connections, as well as PCM and DSD audio via USB. Source selection is shown on the dot matrix LED display. Analogue inputs are identified as IN 1 through IN 6, while the digital inputs are labelled AES, USB, COAX and OPTIC. After approximately 2 seconds, the detected sampling rate is displayed, with U768 indicating the USB input operating at a 768 kHz sampling rate.

Source selection can be controlled remotely when the rotary switch is set to the Remote position. The 45 mm aluminium volume control knob is milled from solid material and operates the motorised Alps RK27 Big Blue potentiometer. A red marker LED shows the volume setting in darkened environments. The volume control can be operated with any infrared remote control, and the Director MK 2 can learn its commands at the press of a button.

The integrated DAC automatically detects the sampling rate and resolution of the connected digital source, whether this is a streamer, computer or CD player. No further settings are required on the SPL Director MK 2. The detected rate appears on the dot matrix LED display, for example U768 for USB at 768 kHz.

DAC768

The DAC768 uses an AKM AK4490 Velvet Sound™ DAC chip. It converts PCM audio at up to 32-bit resolution and 768 kHz sampling rate, equivalent to 16 times CD resolution. Direct Stream Digital is supported up to DSD4 or DSD256. Compared with the DAC 768xs, the DAC768 adds an AES/EBU digital input and the SPL DLP120 with VOLTAiR technology.

DLP120 (Dual Low-Pass)

The DAC chip's analogue output is filtered by 2 low-pass filters, one for PCM audio and one for DSD audio. They use different roll-off frequencies for the 2 signal types. The filters are built with VOLTAiR technology, providing increased dynamics and headroom.

SPL develops its Professional Fidelity products both to a planned design and by ear. Many important components are fitted to the circuit boards using through-hole technology, allowing SPL to select the components used in the circuit.

VOLTAiR Technology

VOLTAiR is SPL's 120V reference technology. It operates at a DC voltage of 120 volts, which is 4 times the voltage used by IC-based semiconductor operational amplifiers. The audio operating voltage supports dynamic range, signal-to-noise ratio and headroom, as well as detail and a relaxed listening experience.

The 120V technology operates at +/-60 V. SPL developed the proprietary SPL 120V SUPRA operational amplifiers to handle this voltage. Conventional components and operational amplifiers would be damaged by it.

The 120V designation refers to the operating voltage inside the device, not the local mains voltage from the power socket. The internal linear power supply uses a toroidal transformer to convert the mains voltage to the required secondary voltage. Rectifiers then convert this AC voltage into the DC voltage required by the audio circuitry.