SPL Director DA Converter
Director is a full-fledged stereo preamplifier with an extraordinary DA converter.
There is provision for connecting up to six stereo sources – two in the analog domain offering RCA connectors for e.g. phono preamplifier like the Phonos and four in the digital domain with USB, AES, Coaxial and Optical connectors. At the output side a power amplifier or active loudspeakers can be connected balanced (XLR) and unbalanced (RCA). We recommend the Performer s800 as power amplifier in order to maintain a 120V Rail audio chain from the DAC to the speakers for best audio performance.
Volume is controlled strictly in the analog domain – for good reason. Commonly volume is regulated in the digital domain as part of a chip's functionality. Apart from being inexpensive the down side is that the playback at lower volume than unity gain (0dB) is compromized due to a shrinking bit resolution. And as you never listen with the preamp turned up fully clockwise you always hear at a lower bit resolutions with diminished audio fidelity. It makes not a lot of sense to listen to high res audio then, does it? As this is not acceptable we opted for an analog solution that gives you infinite resolution at all listening levels. We use a motorized ALPS RK27 "Big Blue" potentiometer with excellent feeling and channel matching. Being motorized Volume can be remotely controlled.
A great feature is a small DIP switch at the bottom of the Director. DIP switches number 3 and 4 allow to decouple the volume control and to deliver a unity gain output at the XLR or the RCA output or both. You can connect a headphone amplifier like the Phonitor e and have individual volume control for the headphones. Another application is that connection of a digital recorder.
On the front of the Director is a toggle switch for the selection of the input source. Toggle to the left to select the previous source and toggle to the right to select the next source. The selection is shown in the dot matrix display: IN 1 and IN 2 for the analog inputs and USB, AES, COAX and OPTI for the digital inputs. The detected sample rate of the selected digital input is displayed after about 2sec. (e.g. U384 = USB input, 384kHz sampling rate). The input source can also be remotely controlled.
Volume as well as input selection can be remotely controlled using any existing infra-red (IR) remote control. The cool part is that the Director learns your remote! Take, for example, the remote control of the CD player. Out of the many buttons there are maybe four you hardly use if at all and that do not directly trigger a function on the CD player. Alternatively you can use the Apple remote control which is small, slick and offers just the buttons you need. Assign Volume Up / Volume Down to two buttons and Next Input / Previous Input to two other buttons and let the Director learn them. The procedures are described in the manual.
The Director is equipped with the best Digital-to-analog converter (DAC) we ever made. It sports four digital stereo inputs (USB, AES, Coaxial and Optical) and supports PCM audio as well as DSD audio playback.
World Premiere Design with VOLTAiR technology
We have been looking at many DAC designs and we have always wondered why all the innovations happen on the digital side. Almost no innovation is to be found on the analog part for the DAC. Maybe that is because most designers have a background in digital engineering and as a result they apply only standard 'cook book' designs on the analog side. We, having a little background in analog, find cook book design out dated and boring. We believed we can do that part much better and –simply put– revolutionize the design of DACs. Here is how:
The output of a DAC chip is either a voltage or current (as in our design) that represents the value presented on their digital inputs. This output is to be converted to voltage (in case of a current output) and filtered with a low pass filter. These two stages are typically designed with the same reference voltage of the DAC chip at e.g. 5V. Think about this: the first stage that the analog waveform is exposed to has a headroom limited to 5V. Now imagine this to be 120V! This is what we have done in the Director. The current to voltage conversion as well as the low pass filter are both running on a 120V rail - our VOLTAiR technology. The incredible headroom and the enormous power lets the analog wavefront come to life and evolve without limitations. And that is audible. Very much so.
SPL Director DA Converter Features
- 120V rail preamplifier with integrated DA converter
- Four digital inputs: USB, AES/EBU, coaxial, optical
- DAC: up to 384 kHz (PCM) and DSD 2 (Double Rate DSD, DSD128)
- Win driver; Apple class compliant
- Two analog inputs (2x RCA)
- Balanced and unbalanced outputs (XLR, RCA)
- Analog volume control with motorized ALPS R K27 "Big Blue" potentiometer; remote controllable (learns any IR remote control)
- Remote controllable source selection (learns any IR remote control)
- Avago dot matrix display shows selected input and sample rate frequency for digital inputs
- Frequency range (analog): 4 Hz to 300 kHz (-3 dB)
- THD: 0,0008 % (analog), 0,0004 % (digital)
- Dynamic range: 137,6 dB (analog), 120,8 dB (digital)
- AMP CTR connection to Performer power amplifier for coupled on/off switching
- Windows® driver, Apple class compliant
- Stand-By/power on switch
- Linear power supply with toroidal transformer
- Made in Germany
SPL Director DA Converter Specifications