Audio Note DAC 5

Stereotimes Review (Summary)

The Audio Note DAC5 is the most unique digital product available today. It uses the most unusual and innovative digital circuit on the market, 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 over sampling, 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 to 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) DAC5 have no over sampling, 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. It uses the highest grade Analogue Devices AD1865, 18Bit stereo converter chip solely because we found it to be the best sounding available (yes, even better than the 20Bit versions!).

The filter-interface coils / transformers are of the highest possible quality, using 80% nickel Super mu-metal cores with 99.99% pure Audio Note™ silver wires. The air gaps in the two filter coils per channel 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 DAC 5 Special features an upgraded version of the M6 pre-amplifier line stage, using a 5814a (ECC82/12AU7a) and a 6463, both of which are dual triode valves. These are coupled to an output transformer, wound with Audio Note (UK) silver wire on a High B C-core. With a 33:1 step-down ratio, this output transformer not only has exceptionally wide frequency response, but also just about the absolutely best dynamic transfer function possible. The analogue output has provisions for both unbalanced and balanced operation, using the best available quality RCA and XLR connectors.

The DAC 5 Signature features an upgraded version of the M6 preamplifier line stage, using a 5814a (ECC82 / 12AU7a / 6189) and a Telefunken 6463, both of which are dual triodes valves. These are coupled to an output transformer, wound with Audio Note (UK) silver wire on a 55% Nickel Audio Note (UK) Supa-Perma C cores. With a 33:1 step-down ratio, this output transformer not only has exceptionally wide frequency response, but also just about the absolutely best dynamic transfer function possible. The analogue output has provisions for both usingle ended and balanced operation, using the best available quality RCA and XLR connectors.

To power this spectacularly revealing arrangement, we have incorporated a dual channel power supply with double choke filtering and valve rectification. 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 is an exceptionally low noise, shunt-type.

Internal component quality of this calibre has never before been seen, in either consumer or professional equipment. There is an abundance of Black Gate and Cerafine Audio capacitors, and Audio Note (UK) Tantalum film resistors throughout the circuit. Analogue stage filter inductors and internal wiring are all produced with Audio Note (UK) 99.99% pure silver wire.