[ Home | Staff & Contacts | DIY & Tweaks | Listening tests | HiFi Playground | Music & Books ]

AudioNemesis DC-1 DAC

Heresy and Black Magic - Part 1

[Italian version]

Product: AudioNemesis DC-1 Digital-to-Analog-Converter
Manufacturer: AudioNemesis - Italy
Cost: 495 Euro
Reviewer: Giorgio Pozzoli - TNT Italy
Reviewed: October, 2005

[DC-1]

Introduction

AudioNemesis.... another new actor in an already overcrowded environment, you are thinking.

Well, not really. AudioNemesis is the new brand name by Fabio Camorani, a well know audio engineer (perhaps even more abroad than in Italy...) with a long experience in audio design. We already met his previous brand name, AudioNautes, when we reviewed the LC Clock XO. This brand also sells very high quality vinyl.

AudioNemesis is currently producing a DAC, but a full line of very unconventional electronics is under development.

Camorani has been in touch with Japanese designers for years, and the approach of his products is clearly biased in this direction, even though corrected by a very personal touch. The electronics brand sound is sweet, detailed, precise. Understatement is the key word.

They are specifically designed to work with non conventional speakers: single-drivers, or Japanese-style multi-drivers, with large woofer and/or horns.

The stated philosophy is to "make it as simple as possible, but not simpler": I appreciate a lot this approach, because it exactly matches my idea of audio design.

In any case, it is clearly a non conventional approach.

This cannot be said of this DAC. No, here we go far far beyond, here it is pure heresy....

Construction

The unit is half size, but not so small, measuring 23 x 8.5 x 34 cm. IMHO, it is really beautiful, for the price. The front panel is a thick slab of beautifully worked Plexiglas(R) with only the AudioNemesis logo, which lights up in blue, and the DC-1 label, in white. No other element, apart really unobtrusive screw heads, disrupt the elegance, solidity and smoothness of this panel.

The box is very solid. The structure is very similar to the black Linn components one: the chassis is obtained from a metal sheet and integrates the bottom plate, the rear panel, the internal supports for the front panel and sides. The cover is another metal sheet bent to form top and the sides. The cover has a further bend at the rear end so that the it gains further rigidity.

The external panels are perfectly silent when knocking over them. Like with Linn products, the merit is apparently of the powder coating. In this case there is a rather thick, metallized, dark gray coat, very rough at touch. I did not test it for anti-scratching, but it is said to be very resistant. In any case, it is one of the best coating I have ever seen in a low cost product.

[Rear panel]

The back panel has, from left to right, an IEC power socket, the two audio output, gold-plated, RCA connectors for left and right channel, the electrical digital input, gold plated, RCA connector and below it the lock error led. As per the stated philosophy, only what is needed and nothing more. But here too quality is not an issue.

Taking in your hand the unit the effect is of a extraordinary solidity: the weight (3.5Kg) compared with the reduced size has also a part in this feeling.

The unit, however, has also a power supply switch. This is hidden on the bottom plate near the front panel. The high gummy feet allow for reaching the switch very easily (unless you have huge fingers....) without moving the unit. A very clever solution to eliminate a normally clumsy (or in alternative very expensive) switch from the front panel, while avoiding the user strange contortion to get to the back panel...

Technical Approach

As said, the unit is designed to be as simple as possible. Fabio Camorani and Giuseppe Intorrella, who has contributed to the technical and industrial aspects of the project, adopted one of the most popular approaches in Hi End circles, the zero-oversampling, used also in our Convertus and TNT1541. This technique, probably "invented" by Kusunoki, consists in eliminating the oversampling and digital brickwall filter from the digital signal process taking place in the DAC. This means that all the ultrasonic spurious frequencies generated by aliasing in the D-to-A process are emitted by the DAC and potentially reach the ears of the listener. According to Kusunoki, this does not cause any problem, as the ear already has a perfect anti-aliasing filter.

In practice, Kusunoki idea proves correct in listening tests, as the technique produces a very pleasant, relaxed, involving sound, apparently very rich of harmonics, and its main drawback, a drop of a few dBs in the frequency response at 20KHz, does not appear too evident at all.

For the rest, the team choose to have a general high quality level of the (not so many) components and concentrated on a few especially delicate areas.

[PCB]

First of all, power supply is rather special: custom transformer to reduce overall size and stray magnetic fields, a Black Noise power supply filter by Systems and Magic, specially designed and tailored for this unit (it is reported to have positive effects on the overall sound and the low frequency range especially), multiple independent power rectification and parallel regulation units. Not so common at these level of price.

Following the signal path, we see that the unit has an high quality Scientific Conversion digital transformer, which allows galvanic isolation of the digital unit. This is not required by the SPDIF (IEC-958) consumer interface, while is required by the AES/EBU professional standard. In general we can say that the transformer has no effect in the worst case, and can radically solve many ground loop or interfacing problems, especially but not only in complex environments, which is welcome because detecting these problems can be all but easy.

The unit also uses reclocking: there are many types of reclocking, we will be back at this point later on.

The audio output stage is solid state, with discrete components and no input-output feedback, which in my view is the simplest solution to achieve a very good sound. The circuit is as basic as possible, always in the spirit of the general project philosophy: only two devices. This on one side makes the unit very transparent, but has two side effects: a low output (more than enough with all my systems, in any case) and a tubey distortion. Special care has been taken in the selection of output stage resistors (very low noise, metal film, military) and output coupling capacitors: these are ERO brand, and there are two of these in parallel.

Finally, looking at the interior, you can see that many components are covered by or attached to small black blocks: these are carbon blocks that help eliminating any vibration in the circuit. And also helps in hiding the marks of the components used... so yours truly cannot give you any detail.

One detail in any case is patent: the conversion is probably performed by a DAC with less than 24 bits, as the unit cannot work with DVDs 24/96 outputs.

There are also many large ferrite beads, used to suppress high frequency disturbs. All these details are not inexpensive, and very hard to find in low cost DACs.

All here? and why you said it's heretic, then??? Ohhh, no, no, it's not all here... the best is coming next!!!!

In Use

The unit is very simple and straightforward to set up, given the very reduced interface connectors. Given the presence of an input transformer, there are not even big risks of ground loops, at least on the digital side.

The sound instead has been for me a complete surprise!

First of all, I must say that I was using as a reference unit the TNT1541 (without decimation), connected to the same transport: also TNT1541 is a zero oversampling DAC, with the associated 3dB drop at 20KHz, so I expected the sound balance to be definitely similar. Nothing more wrong: the DC-1 sound is far different form any zero oversampling I have listened to.

The general character maintains many of the specific features of zero oversampling: relaxed attitude, quiet (but not slow) pace, overall natural sound.

However, the medium high frequencies are far more present than in TNT1541, which means their balance is similar to a normal DAC, if not a brilliant one. In any case, nothing in common with the terrible low cost players of few years ago: there is an hint of grain, the high end is not perfectly clean, but notwithstanding the relatively bright sound, the DAC is as far from edgy as you can imagine, unless the program itself is edgy. No listening fatigue at all. In turn, this brilliant sound clearly enhances the perceived detail.

Very low frequencies are perhaps a little back and possibly an hint less controlled than the reference. Bass is in any case more articulated, because of the larger presence of higher harmonics.

Speed, as a consequence of the enhanced high frequencies, is good. Impact seems a little reduced, as a direct consequence of less prominent low frequencies. Pace and rhythm are very good.

The soundstage is very wide, even though not especially deep. It is natural, stable and somewhat detailed, but the localization of the sources is not very precise, which is strange, given the sound balance and precision.

Fabio confirms me that he has been explicitly looking for these results, and I can believe him, as they match the other AudioNautes products I have been able to listen to. As said, this is to be used with single driver speakers and large woofers... if an audiophile makes this kind of choice, it means that, in his/her(too rarely, alas) view, control and neutrality is not as much important as detail, speed, dynamics and impact!

Also the soundstage presentation is based on a "naturalistic" approach: in the view of the designer, precise, "pinpointing" localization is irrelevant, as this is completely missing in live events: another heretic statement, but one rather difficult to refute...

Go to [Part 2] | [Part 3]

Copyright 2005 Giorgio Pozzoli - www.tnt-audio.com

[ Home | Staff & Contacts | DIY & Tweaks | Listening tests | HiFi Playground | Music & Books ]