Nakamichi 1000p - DAC + preamp

Najskuplji i najbolji Nakamichi uredjaj ikad, proizveden u vrlo limitiranoj seriji. Spoj je DAC-a najvise klase i STASIS (Pass Nelson, Treshold) FET pretpojacala najvise klase.
- 2 dvostruka DAC chipa TDA1541A S1 Silver Crown (jedan od 2 najbolja DAC chipa svih vremena)
- najbolji DAC modul DA-111p (studijska verzija najvise klase), potpuno diskretni analog stage u A klasi
- XLR ulazi izlazi, zasebni izlaz iz DAC-a ( fiksni ili varijabilni, XLR + RCA)
- 2 toroidna transformatora, 15 visoko stabiliziranih ispravljaca + naponsko rasprezanje za svaki sklop,
- pojacalo za slusalice u diskretnoj tehnici u A klasi
- najbolji Black Beauty Alps potenciometar
- od DAC chipa do izlaza bez ijednog veznog kondenzatora (cisti DC), spindelima podesen offset
- dvostruko kuciste, vanjsko aluminijsko 4 mm potpuno nerezonantno, unutrasnje kuciste od bakra, svaki sklop zasebno oklopljen bakrenim plocama ( prakticki 5 kutija u jednoj kutiji)
- 48 db mrezni filter
- sorbotanske antivibracijske nogice
- kompletno servisirano
- 20 kg

Cijena za ovaj izuzetno rijetki Nakamichijev High End dragulj je samo 3590 €.

Uz doplatu USB to SPDIF konverter visoke klase XMOS U208 Amanero uz pomocu kojeg se na Nakamichi moze spojiti kompjuter, streamer, mobitel, a preko OTG konvertera i iPhone, iPad, iPod…

The D/A converter was developed in combination with the Nakamichi1000 DAT deck in pursuit of the highest sound quality beyond the highest analog deck.

The digital filter uses a 20-bit 8 x oversampling digital filter.

************
The D/A conversion section uses a 20-bit full calibration D/A conversion system.
This circuit uses three key technologies : digital ROM calibration, tandem 20-bit converter, and glitch eraser to achieve extremely high conversion accuracy and extremely low distortion rate at the theoretical limit.

In digital ROM calibration, all bits are digitally corrected by a calibrated ROM that stores correction data for each D/A converter IC. This prevents characteristic changes due to time and temperature, and realizes extremely high conversion accuracy.
Calibration and writing data to the ROM are performed for each unit at the time of shipment from the factory. First, a 22-bit A/D converter for measurement is connected to a 1000p test point in operation to accurately measure the D/A conversion error. Then, the subtle peculiarities of each converter IC are grasped by special arithmetic processing assuming all situations. Then, this error data is written in the ROM, which is mounted on the D to A converter circuit board of each unit. Unlike analog methods such as semi-fixed resistors, the ROM directly adjusts digital data to achieve complete accuracy correction.
This circuit completely eliminates the slight noise associated with the original sound, which could not be eliminated by conventional D/A conversion.

In the tandem 20-bit converter, the 20-bit output of the digital filter is first divided into upper 14 bits and lower 6 bits, then processed by a dedicated 16-bit D/A converter and digitally added again to achieve 20-bit operation. Each D/A converter operates with a sufficient margin. For the lower 6 bits, which require particularly high precision, only the high-order bits of the 16-bit converter are used to achieve linear conversion. For the upper 14 bits, a margin of 2 bits is left to ensure conversion accuracy.
Complete accuracy correction by digital ROM calibration has achieved the 20-bit limit performance.

In a typical D/A converter, a signal contaminated by glitch noise is sent directly to an analog circuit, where the glitch is removed (sampled and held) in an analog manner. However, in this method, the switching noise of the sample-and-hold circuit itself masks a small signal of 60 to 80 dB, making it difficult to reproduce music accurately.
In order to eliminate this glitch noise at the digital data stage, it is equipped with a glitch eraser originally developed by Nakamichi. In this circuit, in order to eliminate the very minute glitch noise at each bit transition except for the 0 cross point, which has been considered as a problem until now, every occurrence point of the glitch is predicted in advance, and it is completely cancelled out, realizing an ultra-low distortion rate of 0.0015% which is the theoretical limit.

The Autobit Calibration System starts automatically when the power is turned on and is tuned to nearly perfect 16-bit accuracy in 1.4 seconds using a digital tuning method to prevent accuracy degradation due to aging.

It employs a twin PLL stabilized interface, and Nakamichi's unique digital data stabilizer and two PLLs shut out disturbances such as jitter superimposed on digital signals.

Equipped with a 32-dot peak level meter that reads digital data directly.
This meter is a professional specification ultra-high precision type with an error limit of ± 0.2 dB. The discrete driving circuit and dedicated LSI enable full static lighting without adversely affecting sound quality.
This meter has a peak hold function and a meter off function.

The audio circuit uses a fully balanced discrete transmission system.

A multi-power supply is used for the power supply section to eliminate mutual interference between stages, and an isolated ground system to eliminate mutual interference via ground.

Resonance braking structure is adopted.

Uses a full static indicator.

Equipped with analog level volume.

Two types of digital input / output terminals are mounted : coaxial and optical.

Equipped with DAT mutual copy function.

Equipped with a headphone terminal with dedicated level volume.

It is equipped with an emphasis switch.