Inventing Da Vinci DAC

How Light Harmonic Created the Da Vinci 384K USB Digital to Analog Converter

Da Vinci is the world's first true bit-perfect 384K asynchronous DAC using USB 2.0 technology.

It's unprecedented, unique, and superb. But don't just take our word for it. Editors have
widely praised Da Vinci's award-winning design and performance, calling it
"state-of-the-art," "way ahead of the curve," "stunning" and "truly outstanding."
And described the music Da Vinci produces as "lively, detailed and fresh,"
"elegant and coherent" and "phenomenally rich."

Like Leonardo Da Vinci, the famed Renaissance artist,
architect and engineer, the Da Vinci DAC embodies superb
digital artistry, innovative product architecture, precision engineering
and a passion for perfection.

Rich with patent-pending technologies, Da Vinci boasts 40 ultra-low-noise
power regulators, dedicated digital power, a three-layer buffer, triple clocking,
and a proprietary audio processing unit. Additional characteristics include a
lifelike soundstage, musical coherence, transparency, and a best-in-class
noise floor.

Read AudioStream's review of Da Vinci DAC here.

Setting a Standard

As in Vitruvian Man, Leonardo's iconic drawing illustrating
the perfect merging of science and art, we set out to make
our Da Vinci a contemporary expression of that Renaissance ideal —
in the form of a digital component that would perform as close to an analog audio source as humanly possible.

To test our progress, Light Harmonic engineers assembled a stellar analog (not digital) audio reference system to serve as a good representation of true high-end sound. The system included a Clearaudio turntable, an SME tonearm, a Koetsu Rosewood cartridge, and an Aesthetix tube phono amplifier. We compared Da Vinci's performance to this set-up throughout our research and development process.

What DACs Do

To the uninitiated, DACs may seem mysterious, even irrelevant. After all, analog systems don't use them. But today, most music exists as packets of binary code on CDs, DVDs, the Internet, and in an expanding library of file formats, like MP3.

Simple in theory, complex in execution, audio DACs convert digital codes into analog or physical form so they can be fed into an amplifier to drive speakers and be heard. CD players, iPods, other digital music players, PC sound cards, and the like already come with DACs, usually as integrated circuits. High-end audio systems include more capable standalone DACs.

DACs also reconstruct signal information from music samples, but this can introduce errors that show up as low-level noise. Filters, oversampling and other techniques can reduce or eliminate most noise. But there are many varieties of DACs and many techniques to perfect their performance, making DAC design almost as much of an art as it is a science.

How Da Vinci Shines

Light Harmonic designed Da Vinci from the ground up, incorporating the latest thinking, developing new technologies, and addressing a multitude of issues, including the following:

Automatic LSB Correction
As research advanced, we confronted the Least Significant Bit (LSB) extension error, a problem that plagues every currently available DAC. LSB is a mathematical error affecting 16- and 24-bit digital files that causes a mismatch of up to three percent in every note. Da Vinci solves this with new and proprietary technology that automatically corrects each music sample.

Precision Timing
In digital signal conversion, timing is everything! To ensure computer speed fluctuations would not influence Da Vinci, and that it would run at a constant speed, Light Harmonic developed a proprietary (and patent-pending) Three-Layer Buffer similar to the buffering technology many of today's high-speed computers employ. This is the first time such a design has been applied to audio.

At the same time, our Triple (3X) Clock architecture divides the tasks usually handled by one clock among three clocks — one for 44.1K audio, a second for 48K audio, and a third for USB signal transmission. Da Vinci also uses the best non-phase-locked loop (PLL) clocks, which are set very near the analog conversion module. Advanced computer simulations and PCB modeling ensures that the transmission length of each digital audio signal is identical, with a maximum possible error of one one-thousandth of an inch.

No Up or Over-sampling
Light Harmonic's analysis suggests that 99 percent of audio DAC manufacturers upsample and over-sample. This makes measured numbers appear impressive, but the DACs doing this never sound quite right to our ears. We even tried, during Da Vinci's gestation, to make the industry's best upsampler using top-level delta sigma conversion technology and a finely tuned digital filter. But the results couldn't compete with our analog reference system, and we scrapped them. In the end, we stuck to our guns: bit-perfection all the way!

Technical Specifications
Type Digital-to-Analog Converter
Finish Options Standard: Black
Upgrade: Silver
Dimensions 18.5" (L) x 18.5"(W) X 7.87" (H)
Weight 61 lbs/28.0 kg
Converter Type Bit-perfect R2R architecture with patent pending 3-layer buffer.
Analog Outputs Output Levels: 2.05V rms unbalanced / 4.1V rms balanced.

Balanced Outputs - 1 stereo pair on 3-pin male XLR connector (pin 2 hot).

Unbalanced Outputs - 1 stereo pair on RCA Phono connector.
Digital Inputs 1x Asynchronous USB 2.0 interface on standard USB-B connectors. Will accept up to 32 bit PCM at 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384K S/s

1x Asynchronous AES/EBU on 3-pin female XLR connectors. Will accept up to 24 bit PCM at 44.1, 48, 88.2, 96, 176.4, 192K S/s.

1x Asynchronous SPDIF on one RCA Phono connectors. Will accept up to 24 bit PCM at 44.1, 48, 88.2, 96, 176.4, 192K S/s
Clock Frequencies 3X Clock architecture without PLL. TCXO with -166 dBc/Hz @ 10MHz. 45.1584M Hz for 44.1, 88.2, 176.4, 352.8K Mode. 49.152M Hz for 48, 96,192,384K Mode. 13M Hz for USB interface.
THD+N (unweighted) Better than 0.0018%
Frequency range: 20Hz - 20kHz
LSB Auto-Correction Always enabled
Residual Noise
(unweighted)
Better than –115dB @ 20Hz - 20kHz
Residual Noise
(A-weighted)
Better than –125dB @ 20Hz - 20kHz
Channel Separation
(Crosstalk)
-142dBFS @ 10kHz
Filters Digital Filters: None.
User selectable Analog Filter: -3dB @ 100K Hz.
Power Supply Factory set for 115~120 , 220~230 V AC, 49 – 62Hz.
Power Consumption 2 Watts in Standby mode/ 58 Watts operational maximum

Core Conversion
Da Vinci refrains from using common delta-sigma integrated circuits (ICs) for the digital-to-analog conversion modules at its core. Instead, we use precision resistor-ladder architecture with low noise, a complex programmable logic device, parallel mechanisms for core conversion, and eight of the finest shunt local regulators we could build. The result: precise signal conversion.

Proprietary Duet Engine
Our patent-pending Duet Engine effectively doubles low sampling rates without digitally up- or over-sampling signals or using digital filters. Instead, sophisticated aligned analog interpolation does the trick. The result: Duet Engine technology delivers smoother highs and eliminates any need for a so-called brick-wall filter to cut off audio signals above or below a selected frequency. The improvement is especially apparent when listening to CDs.

Pristine Analog Output
Instead of opting for negative feedback, off-the-shelf integrated circuits or operational amplifiers, we created a unique, proprietary analog stage to achieve the output needed to meet Da Vinci's demanding goals.

The stage consists of a dual mono, discrete, balanced, single-ended Junction Field Effect Transistor (JFET) with an output buffer and non-negative feedback. It uses no operational amplifiers, and the buffer has far fewer high-order harmonic distortions than other designs. We've found this offers a more natural sound, especially in the high frequency range, even if at the expense of what we consider to be synthetically impressive measurements.

Six-Piece Aluminum Chassis
Solid as a brick, Da Vinci possesses the best-designed chassis in the industry. It is constructed of CNC-milled aerospace-grade, 6061-T6 aluminum blocks, which provide exceptional thermal stability, resonance control, and shielding from radio and electromagnetic signal interference. Special damping materials between the chassis's several layers minimize internal vibrations, and Da Vinci's 61-lb. weight and unique shape effectively eliminate vibrations from outside sources.

Multistage Isolated Power
Da Vinci's unique design enhances its appearance while also isolating the power supplies and preventing overheating. Set in the lower half of the two-piece chassis, the power supplies handle all AC to DC conversions, the display and controls, and the clocks. The lower half also houses a uniquely shaped heat sink that ensures Da Vinci runs within specific temperature tolerances.

To minimize AC and inter-modulation noises, Da Vinci employs more than 40 high-quality regulators, including 8 discrete shunt regulators in the primary digital conversion module, 3 nano-volt noise regulators in the clock power circuit, 5 high-precision regulators in the USB module, and 8 high-current discrete shunt regulators for each channel of the analog output and buffer. An R-Core transformer ruthlessly minimizes electro-magnetic signal interference.

Conclusion

Da Vinci is the culmination of thousands of hours of R&D by engineers and designers dedicated to making the best digital-to-analog converter on the planet. The results have been described, as noted above, as "stunning," "impressive" and "way ahead of the curve."

When we set out to design Da Vinci, we wanted its audio to be as close to a superb analog source as possible. We believe we've accomplished our goal, and offer it to you now.

To try Da Vinci out for yourself, we invite you to visit your local dealer.