Audio Note DAC 4.1x IZVOR

Conceptor’s Note

​The IZVOR distinguishes itself as the first-ever DAC to use large, hand-soldered resistors rather than the usual surface-mount components typically found in ladder DACs.

Darko was able to fine-tune the IZVOR’s voicing by testing and selecting components from our vast selection of custom options, even going so far as designing an entirely new resistor for the project.

Details

The Audio Note DAC4.1x IZVOR Balanced is one of the most unique digital product available today. It uses our patented and innovative digital circuit, combined with some of the finest components, materials and power supplies possible. 

Extensive research into the fundamental properties of the data stream itself have shown beyond doubt that, regardless of the theoretical advantages of the signal manipulation employed in our competitors products, such as higher oversampling, noise shaping, re-clocking or jitter reduction, these corrective measures greatly interfere with the critical time domain requirements of the signal. 

Music is a time continuum from start to end which when broken is irreparably damaged, and no amount of clever manipulation can restore it to its original time / frequency / amplitude duration or relationship, regardless of what the theorists may tell you. 

As a result, we have developed a way of excluding or bypassing all these corrective measures, to allow the conversion from digital to analogue to be done without any manipulation whatsoever. All we do is reformat the data stream to allow the converter chip to be able to interpolate the incoming information correctly. 

In other words, the Audio Note (UK) DAC4.1x IZVOR Balanced has no oversampling, no jitter reduction, no noise shaping and no re-clocking. Having removed all of the digital filtering that is required for over sampling, all filtering is done in the analogue domain where it is easier to retain good, wide band phase-frequency and dynamically coherent behaviour.

Design and Components

Once the audio signal exits the IZVOR discrete R2R Ladder DAC module, it is fed into a pair of our in-house designed and manufactured copper / copper filter-interface transformers. The air gaps in the two filter coils are matched across the full frequency range to within 0.1dB of each other, using a specially designed program to supplement an Audio Precision System 2 test rig.​

The two versions of the DAC4.1x IZVOR Balanced feature an upgraded version of the M6 preamplifier line stage, using a ECC82 and a 5687 (6463 in the Signature version), both of which are dual triode valves. These are coupled to the output transformers, which are wound with Audio Note (UK) copper wire for the primary and secondary With a 33:1 step-down ratio. These output transformers not only have exceptionally wide frequency response, but also just about the absolutely best dynamic transfer function possible. The analogue output provides both single ended / RCA and balanced / XLR connections.​

The DAC4.1x IZVOR Balanced features a choke filtered power supply with valve regulation and rectification, as developed for the M2 range of preamplifiers. 

For the DAC4.1x IZVOR Balanced Signature, we chose to use a version of our patented Galahad feed-forward power supply, as used on our M6 preamplifier.

This PSU features full valve rectification, regulation and voltage stabilisation. This technique not only provides excellent isolation between the digital circuitry and power supply, but also provides well-isolated short and clean analogue signal paths.​

The digital power supply for both models is an exceptionally low noise, shunt-type, designed specifically for the DAC by Andy Grove. It is a solid-state interpretation of our Galahad feed-forward power supply, making it possibly to reach a −130 dB noise floor.

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Some of the superior quality components used in the DAC4.1x IZVOR Balanced include: -

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IZVOR Module; 1w non-magnetic Nichrome resistors

Audio Note (UK) 0.5 Watt and 1 Watt non-magnetic Tantalum resistors

Audio Note (UK) copper foil signal capacitors used in critical areas

Audio Note (UK) Standard and Kaisei NP electrolytic capacitors used in critical areas

In-house designed and manufactured copper / copper interface transformers

In-house designed and manufactured copper / copper SHiB core output transformers

In-house designed and manufactured BA I-E mains transformer

In-house designed and manufactured I-E PSU choke

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Some of the superior quality components used in the DAC4.1x IZVOR Balanced Signature include: -

​

IZVOR Module; 1w non-magnetic Nichrome resistors, silver lead-outs

Audio Note (UK) 1 Watt non-magnetic Tantalum resistors

Audio Note (UK) copper foil signal capacitors used in critical areas

Audio Note (UK) Standard and Kaisei NP electrolytic capacitors used in critical areas

In-house designed and manufactured copper / copper interface transformers

In-house designed and manufactured copper / copper UHiB core output transformers

In-house designed and manufactured I-E mains transformer

In-house designed and manufactured I-E PSU choke