The Slavic word ‘Izvor’ can have many meanings, but principally, the origin or source stood out and best reflected the intention behind this project. For me, ‘Izvor’ represented going back to the fundamentals of digital-to-analogue conversion, exploring the engineering essence while staying in harmony with the materials and metallurgy.

This twelve-year project has been driven by a passion to return to the basics, using selected, well-known and refined components to create a harmonious, discrete multibit digital-to-analogue converter.
Why? Because when you Because when you apply a carefully balanced group of parts, every step forward yields a fuller, smoother, and richer performance, without changing the underlying circuit. In much the same way musical instruments are made, the key to superb audio design lies in harmony and complementary properties of all the components, and the Izvor DAC is no exception.

But this project did not come without its challenges. The resistors I wanted to use have a tolerance of 1%, which (if used in a conventional way, as other manufacturers do) is insufficient even for 14-bit performance in a discrete segmented DAC. So, we had to think creatively and look for innovative solutions.

The technical design target was to stay within the AD1865 DAC chip specification, but to improve it both objectively and subjectively, especially at very low signal levels. This Discrete DAC was modelled and designed around a segmented structure; 3 bits in the MSB and 16bits in R2R sections. Particular attention was given to performance below −60 dBFS, where ambience, decays, and subtle details live. Izvor’s settling time was never in question due to a specific choice of the analogue switches and very careful decoupling.

Sound wise, the goal was to achieve greater contrast and grip, improved authenticity and timing, but at the same time, a very composed and lush presentation.

To achieve this, we developed fast I2S real-time compensation and used measurement equipment with reliable 1-ppm accuracy. Corrected values were stored individually on each DAC board, each being effectively unique. This kept my friend and colleague Andrejs, who was helping write the code, very busy.

There is no oversampling and no digital or analogue filtering, only a circular I2S buffer.

We tested everything at DC-level precision using an 8.5-digit laboratory instrument. The final result exceeds the AD1865’s measured dynamic range by more than 4 dB, and subjectively, the way the DAC loads the room feels far closer to an analogue source.

None of this would have been possible without the shunt power supply, designed specifically for the DAC by Andy Grove, to support such demanding requirements. It is a solid-state interpretation of our patented Galahad feed-forward power supply, with milliohm output impedance, no less than 450mA through the specific MOSFETs, resulting in a spectacularly low output impedance.

Even before the loop was closed and combined with a strong cancellation (inverse of the shunt’s MOSFET transconductance), it was elegantly and easily possible to reach −130 dB noise floor. Schottky diodes and modest capacitance were chosen for liquidity and the absence of mechanical hardness.

We also evaluated nearly the entire range of Audio Note resistors. Although some Nichrome types came close in very strict technical terms, further refinement in metallurgy was required, resulting in a custom full silver Nichrome version for the Level 5 Fifth Element Izvor. Sonically, they were not just ‘slightly better’, they clearly produced a significantly smoother and more elegant sounding choice.

So, has it been worth the twelve-year development? Absolutely. After investigating seemingly endless permutations, personally, I couldn’t be more satisfied with the Izvor. Darko Greguras Izvor technology is available for all models in the following product ranges: DAC 4.1

Darko Greguras

Izvor technology is available for all models in the following product ranges:
DAC 4.1 Balanced, DAC 5, Fifth Element.

Audio Note (UK) Ltd
01273 830 800
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If you would like more information, please contact

Mr. Eddy Chung
hf-inquiry@elephant.com.hk
+852 9303 3156