The Vertex AQ Aletheia dac-1 is unusual in having no upsampling or noise-shaping in its design. Results emerging from their Measurement Initiative with one of the MoD's research agencies show that such processing can break up the musical flow.
Instead, Vertex apply the extensive RFI* and EMI* technology that they have developed over 11 years right in the heart of the DAC to individual components.
Even greater care is taken with the dac-1.5
, using expensive, exotic components throughout the design and implementing vibration and RFI absorption even more comprehensively. The result is a yet higher retrieval of fine detail, a noticeable gain in naturalness and timbre of instruments and voices.
The sound of both DACs is rich, vibrant, incisive yet smooth, without a hint of treble grain. As musical complexity builds, it remains incredibly easy to follow - bathing the listener in a dazzling display of musical interplay and emotion. The presentation is also incredibly transparent – the DACs regularly revealing new sounds in even the most familiar recordings.
The dac-1 has received a glowing report in the magazine hifi+ where Alan Sircom realises that it has actually affected his appreciation of music – almost re-wired his brain. After the DAC had been returned he realised: "This was mourning for the loss of music. That’s how far under your skin the Aletheia gets and I can think of no recommendation higher than that." Download the full review: dac-1 hf+85-1.pdf
The very experienced reviewer Paul Messenger also wrote enthusiastically in HIFICRITIC about his time with the dac-1 and discussed the significance of different CD transports. More information here dac-1 and links to the review and how well the dac-1 scored against the competition.
Vertex's research with the MoD's Acuity agency has revealed what they describe as "tracking errors" with many music systems, where the equipment fails to follow rapid changes in the music. Think of a heavy lorry (the whole system) compared with an agile sports car (the music signal), each driving fast on a twisting country road. At every bend the lorry will be sluggish, tend to overshoot and be slow to recover, while the sports car will confidently jink and dive and be both more precise and much faster.
Tracking error becomes increasingly obvious as music – such as heavy Rock or dense orchestral music – builds in complexity and volume, creating more damaging acoustic energy to be carried around the system.
The Aletheia DACs employ 16 bit D-to-A conversion with no oversampling, to reduce processing complexity, and have no noise shaping or filtering, to avoid possible phase shifting, filter ringing and break-down of signal integrity. The DACs are deliberately very basic in processing terms, with the majority of the design effort – right down to a component-by-component level – focused on reducing those interactions that plague systems.
There is extensive RFI and microphony reduction throughout the designs, more in the dac-1.5, and an ultra high-quality, dual-stage power supply topology is used. Analogue output is passive thus avoiding active output stages and output capacitors are Mundorf Supreme (silver/gold in oil) and Duelund solid copper foil CAST in the dac-1.5.
An example of the quality of the internal components is that the power supply is filtered with the equivalent of a Vertex HiRez Jaya shunt filter that alone costs over £1000 as an external plug-in mains cleaner.
Input and output socket panels, isolated from the chassis, SPDIF and Optical inputs on the right, RCA single-ended and XLR balanced outputs on the left. Switches toggle between the inputs and outputs and turn front panel LEDs on/off.
Quite apart from the care taken with the internal components, another sign of the thought that has gone into the DACs is that the input and output sockets are mounted on isolated panels that reduce acoustic energy input to the circuitry from the rest of the system.
Digital sources can be conventional 16bit/44.1kHz SPDIF signals into the RCA or BNC sockets, or up to 96kHz signals into the TOSLINK optical socket. Outputs are both single-ended RCA and XLR balanced.
Read a detailed description of the design ideas and the refined Vertex technology that is built into these highly unusual DACs – aletheia handbook 1.pdf and more information on the design and specifications Vertex DACs
Prices: £10,995 dac-1 and £15,995 dac-1.5
Why Aletheia? The Wikipedia entry reads: "disclosure" or "truth". The literal meaning of the word ἀ–λήθεια is "the state of not being hidden; the state of being evident" and it also implies sincerity, as well as factuality or reality.
* RFI – radio frequency interference, EMI – electromagnetic interference