O ψηφιακός της NAD...

[Κώστας Φ.]

O πιό ακριβός ενισχυτής στη γκάμα της NAD, με ψηφιακή είσοδο και 250W στο κανάλι (500W peaks).
[Βασισμένος στην τεχνολογία της Zetex (για την οποία έχουμε συζητήσει αρκετές φορές στο παρελθόν εδώ μέσα - μία αναζήτηση για τον όρο "Zetex" θα σας πείσει).]

NAD’s first fully digital amplifier is the industry’s first digital amp that performs as well or better than the “very best linear Class A or AB amplifiers” with Class D efficiency, product development director Greg Stidsen contends.

The amp is the $4,999-suggested Master Series M2, which is rated at 2x250 watts into 4 or 8 ohms with 2x500-watt peaks and 120dB dynamic range. It ships in June to retailers authorized to sell NAD’s top-end Master Series components.


The M2 directly accepts a digital PCM signal, uses pulse width modulation (PWM) to amplify the signal, and incorporates a new type of closed-loop direct digital feedback technology to deliver better-than-Class-A performance at all output levels with 89 percent efficiency at 2x250 watts, Stidsen said.


Compared to a handful of other truly digital component amplifiers, Stidsen continued, “our amplifier is one-third the price with higher power, less distortion, and more dynamic power output.” At $4,999, it’s the most expensive amp in the NAD lineup, which previously topped out at about $2,000, but it nonetheless reflects NAD’s position as delivering audiophile performance with value, Stidsen said.


Truly digital amps promise high levels of performance but haven’t lived up to their potential, so they haven’t been embraced by the audiophile community, Stidsen said. Truly digital amps, he explained, accept a digital PCM signal, whereas other types of amps, including Class D amps, take in an analog audio signal. Direct digital inputs “eliminate analog conversion, cable issues, and lots of analog stages where you can lose information and add distortion,” he explained.


NAD’s collaboration with Zetex takes digital amplification to audiophile levels by using closed-loop digital-domain error correction developed by U.K.-based Diodes Zetex Semiconductor. “All the previous drawbacks of digital amplifiers are simply removed by use of digital feedback,” said Franz Riedlberger, Diodes Zetex’s director of research and technology development. “Power supply noise and output-stage distortion are rejected, and output impedance is very low.” As a result, he said, the M2 delivers “the lowest available distortion and noise coupled with outstanding linearity, leading to a detailed and natural sound.”


The feedback technology differs from traditional feedback technologies that loop the amplifier’s analog output to the amp’s input, NAD said. The company contends such methods are “too slow.” Diode Zetex’s Direct Digital Feedback Amplifier (DDFA) closed-loop technology, on the other hand, “corrects for the analog output in the digital domain” with a bandwidth wide enough to prevent any truncating of the original signal’s information, Stidsen said.


The M2’s chassis incorporates digital/analog converters to connect directly to a source’s digital PCM output, basic digital-domain preamp functions except for tone controls, and a PWM amplifier section. For connection to sources with analog outputs, the device features analog/digital converters, single-ended analog stereo inputs, and balanced XLR inputs. The digital inputs include coax, optical, and balanced AES/EBU. Other features include dual-mono power-supply design, two analog outputs per channel to simplify speaker biwiring.


In the device itself, NAD married Diode Zetex’s technology with some of its own proprietary technologies to boost performance. NAD’s technologies include PowerDrive to deliver high-power transient peaks and drive difficult speaker loads without upping distortion levels. Other NAD technologies are digital soft clipping and digital volume control.


In the future, the digital amplification technology could be incorporated in multichannel home theater amps, and such products could include built-in decoding of Blu-ray surround formats because the amp would have DACs and a basic preamp already built in, Stidsen said. The technology could also appear in $2,000-$3,000 AV receivers and be price-competitive with AVRs rated at the same power.


“The M20 is an audiophile amp and a test bed for future development to bring the technology to more mainstream products,” he added.


Truly digital amplification based on a Texas Instrument chip amp appear in many low-power moderate performance HTiBs, but they don’t incorporate closed-loop error correction, said Craig Bell, Diode Zetex marketing manager.

Πηγή: twice.com

 

[costas EAR]

Απάντηση: O ψηφιακός της NAD...

νά'τοι οι ψηφιακοί κι από την NAD....
Τολμώ να πω σε τιμή "κελεπούρι", δεδομένου ότι δε χρειάζεσαι ούτε DAC ούτε προ.

βέρι νάις ιντίντ...

 

[platon]

Απάντηση: O ψηφιακός της NAD...

Στην συγκεκριμενη περιπτωση εχει νοημα, το τι, τσιπακι φοραει το ντακ του?

Επισης αυτο το............ using closed-loop digital-domain error correction τι σημαινει πρακτικα?

 

[pankrok]

Απάντηση: O ψηφιακός της NAD...

απο οτι καταλαβα δεν εχει dac με την εννοια που το γνωριζουμε αρα δεν εχει νοημα και το τσιπακι του

 

[Κώστας Φ.]

τελικά έχει περισσότερο ενδιαφέρον το πράγμα.. Διαβάστε παρακάτω:


NAD Masters Series M2 Direct Digital Amplifier Challenges Paradigms

A Number of “Firsts”

NAD touts a number of “firsts” achieved by the M2 design, including these:

* First digital amplifier to provide “a fully digital signal path” (though both single-ended and balanced analog inputs are also provided, backed by what NAD describes as “a fully balanced, state-of-the-art analog-to-digital converter”).
* First digital amplifier to use “high-speed digital error correction to reduce distortion."
* First digital amplifier to “fully implement digital closed-loop processing (a.k.a. error correction).”
* First digital amplifier to “implement a new technology called Direct Digital Feedback developed by U.K.-based Diodes Zetex Semiconductors Ltd. during its collaboration with NAD on the M2 project.” The NAD press release explains that the M2 incorporates “a unique, custom implementation of Diodes Zetex's patented Direct Digital Feedback Amplifier™ (DDFA) architecture within a Xilinx field programmable gate array to provide a custom platform for blending DDFA technology with NAD's own innovations.”

More Design Details

Unlike most power amplifiers, which provide analog audio inputs only, the M2 provides a much more varied and extensive array of inputs, including two sets of stereo analog audio inputs (single-ended and balanced XLR), plus five sets of digital audio inputs (two coaxial, two optical, and one AES/EBU). Moreover, in a sharp break with typical practice for most power amplifiers, the M2 provides “a DSP (engine that) is custom programmed with NAD's high-resolution digital volume control possessing a broad attenuation range and perfect channel balance.”

One practical upshot of this design choice is that digital source components can be plugged into the M2 directly, obviating the need for a traditional preamp (though the M2 can accommodate preamps, if users so desire).

Interestingly, the M2 also provides “a five-position digital impedance compensation filter allows fine-tuning the top octave to match the selected speaker impedance, resulting in a perfectly flat frequency response at 20kHz.”

Finally, the M2 includes a “unique Digital Processor Loop(that)allows advanced users to insert external digital filters into the signal path.” NAD explains that one intended purpose of the loop is to allow PC and Mac users to access and apply wide libraries of available “crossover filters and room correction programs.”

Πηγή: avguide.com

 

[costas EAR]

Απάντηση: O ψηφιακός της NAD...

ΑΡΙΣΤΟΣ!

Είδες η NAD? Θα τους βάλει τα "γυαλιά"...

 

[vastsar]

Απάντηση: O ψηφιακός της NAD...

ΑΡΙΣΤΟΣ!

Είδες η NAD? Θα τους βάλει τα "γυαλιά"...

Ναι αλλα μονο 250 βατ? Αν εχε αλλο ενα μηδενικο απο πισω κατι γινοταν :137::114:

 

[Κώστας Φ.]

Ε, αυτός πάει για τα περιφερειακά!
Θα βγάλει και μεγαλύτερο λογικά.. Σε αυτόν δεν χωράνε καν οι Sikorel μέσα.

 

[Costas Coyias]

Απάντηση: O ψηφιακός της NAD...

Σηκωμένο καπώ, έχουμε;

 

[costas EAR]

Απάντηση: O ψηφιακός της NAD...

τι να το κάνεις το καπώ... παλιομοδίτικα πράγματα....

τώρα πια δε μπορείς να θαυμάσεις κάτι. Τι να δεις, τα παλμοτροφοδοτικά, τα παλμοενισχυτικά ή τα τσιπάκια μνήμης για τους αλγόριθμους του dsp? Ή τα τσιπάκια γενικώς? Καλύτερα να κοιτάς το PC σου τι έχει μέσα.... Αυτά χάσανε το ενδιαφέρον τους...

 

[Κώστας Φ.]

Nα κάνουμε κι ένα bump στον Zetex-based ενισχυτή της NAD - να τον δουν και οι φίλοι που είχαν απορίες ποιοί Class-D είναι ψηφιακοί (χωρίς εισαγωγικά)..

Ο Robert Harley φαίνεται ενθουσιασμένος από το εργαλείο...

Functionally, the M2 is an “integrated amplifier” that replaces a DAC, preamplifier, and power amplifier. The M2 eliminates from a traditional signal path all the electronics of a DAC as well as the active analog gain stages of a preamplifier and power amplifier. It does this by converting the PCM signal from a digital source directly into a pulse-width modulation (PWM) signal that turns the M2’s output transistors on and off. That’s it—no digital filter, no DACs, no multiple stages of analog amplification, no interconnects, no jacks, no analog volume control, no preamp. The conversion from the digital domain to the analog domain occurs as a byproduct of the switching output stage and its analog filter. This is as direct a signal path as one could envision.

...

NAD believes that the M2’s technology could eventually become the basis for nearly all of its amplification products. In fact, NAD suggested that the M2 was not designed to capitalize on Class D’s functional advantages, but rather to establish a new benchmark of performance in amplification, no matter what the technology.

...

The M2’s topology has interesting ramifications for a system’s overall noise performance. In a traditional system of digital source, analog preamplifier, and analog power amplifier, any noise introduced ahead of the power amplifier greatly degrades the system’s signal-to-noise ratio (SNR). For example, if we start with a CD player with a SNR of 115dB, feed its output to a preamplifier with a SNR of 108dB, and then drive a power amplifier whose intrinsic SNR is 115dB (all great specs), the system’s overall SNR is only 84.1dB referenced to 1W (all SNR numbers are un-weighted). Noise at the front of the chain gets amplified by the power amplifier, no matter how quiet that amplifier is. In the M2, the only source of noise is in the DSP and the switching output stage, and the noise level is completely independent of the gain. That is, the SNR doesn’t degrade at low volume. The DSP’s noise is kept low in part because of the 35-bit data path. The M2 has an SNR of 91dB (un-weighted, referenced to 1W) at any signal level. Indeed, I turned the gain all the way up and put my ear next to the tweeter of the highly sensitive Wilson Audio Alexandria X-2 Series 2 loudspeaker (95dB 1W/1m) and heard no noise.

Περισσότερα στην αρκετά αναλυτική τεχνική περιγραφή στο blog του Harley: avguide.com

Σε μπελάδες θα μας βάλει η NAD...
A, sτα comments κάτω από το άρθρο γράφει και κάτι που θα αρέσει στον costas:

Ηas a sense of explosive power and unlimited dynamic reserves.

:116:

 

[costas EAR]

Απάντηση: Re: O ψηφιακός της NAD...

A, sτα comments κάτω από το άρθρο γράφει και κάτι που θα αρέσει στον costas:

"Ηas a sense of explosive power and unlimited dynamic reserves."

:116:

Αν τυχόν δεν αρέσει ΚΑΙ σε σένα, χιούστον, γουι χεβ ε πρόμπλεμ...:143::135:

 

[GF]

Απάντηση: Re: O ψηφιακός της NAD...

Nα κάνουμε κι ένα bump στον Zetex-based ενισχυτή της NAD - να τον δουν και οι φίλοι που είχαν απορίες ποιοί Class-D είναι ψηφιακοί (χωρίς εισαγωγικά)..

Υποννοεις κατι??:116:
:144: point well taken! Ετσι οπως τα ειπατε (και τα λετε ) ειναι!
Οσωνουπω θα εχω και τα δικα μου "ψηφιακα" !

 

[Dam]

Επιγραμματικά, ποια είναι τα πλεονεκτήματα μειωνεκτήματα του?

 

[costas EAR]

Απάντηση: O ψηφιακός της NAD...

επιγραμματικά, γ@μεί και δέρνει.

αυτό βέβαια, μπορεί να είναι και μειονέκτημα....

 

[Σπύρος Μπλάτσιος]

Απάντηση: O ψηφιακός της NAD...

επιγραμματικά, γ@μεί και δέρνει.

αυτό βέβαια, μπορεί να είναι και μειονέκτημα....

Άστα αυτά...

Χροιές έχει;
Κόκκο;
Γρέζι;
Μικροδυναμικές του τίμπρου;

 

[Κώστας Φ.]

Re: Απάντηση: Re: O ψηφιακός της NAD...

Αν τυχόν δεν αρέσει ΚΑΙ σε σένα, χιούστον, γουι χεβ ε πρόμπλεμ...

Δην τα μπουρώ ηγώ αυτά! Μη τρουμάζουν!
(Are u f*ckin' kiddin' me?! )

Οσωνουπω θα εχω και τα δικα μου "ψηφιακα" !

Ε, πες ντε!

 

[costas EAR]

Απάντηση: O ψηφιακός της NAD...

Άστα αυτά...

Χροιές έχει;
Κόκκο;
Γρέζι;
Μικροδυναμικές του τίμπρου;

έχει ντελικατέτσα.

μετράει?

 

[GF]

Απάντηση: Re: Απάντηση: Re: O ψηφιακός της NAD...

Ε, πες ντε!

http://users.otenet.gr/~msagfle/IMG_4623.JPG :144:

 

[PAULT]

Απάντηση: O ψηφιακός της NAD...

Ο τετρακάναλος της T-AMP δεν είναι?Εντυπώσεις?