voici le câble ultime digital de Greg Palma, un câble de référence plébiscité par la presse Américaine.
le meilleur compliment que je puisse lui faire est que quand il est connecté,j'ai l'impresion qu'il n'y a rien entre mon Ultradisc 2000 et mon DSP 9000.
un Câble de référence....
Digital-Precise
Super Hybrid Precision Balanced/Coaxial Digital Cable System
Introduction
The Digital-Precise product provides a superior digital connectivity system for demanding digital audio applications. It is quite possibly the only choice for interconnection in today’s environment and with today’s systems.
Balance, Balance, Balance
Digital-Precise completely re-defines the concept of balance in cable connectivity systems.
In all areas of life; technologically, physiologically, artistically, balance is required for success, efficiency, and esthetic appeal. The Digital-Precise product brings balance to digital inter-system connectivity and this directly results in superior electrical signal quality and spectral purity.
Before the evolution of this remarkable product, high technology digital audio systems were interconnected with inferior cable systems. Could you imagine removing the inflated-air tires on a Rolls Royce and replacing them with solid steel wheels? What a tragedy!
Many manufacturer’s of digital audio systems have achieved tremendous performance in their electronic systems, only to have their exceptional sound hampered by low-tech connectivity systems.
Digital-Precise is a true balanced system. It uses two of the same precision coaxial cable for each of the conductors: the hot lead and the return lead. Most existing systems simply use a floating coax where the hot lead is the center conductor and the return lead is the shield. Such systems are nonsense! They are begging for conducted interference from the environment.
In a digital audio environment, there are many interfering emissions in the air surrounding the digital equipment. These interfering emissions do not belong in the digital signal and can cause jitter and inter-symbol interference. To a discriminating audiophile, this interference can be easily heard/detected.
Digital-Precise rejects these signals by canceling with an exceptionally well-balanced cable/transformer circuit design manufactured with the greatest care and craftsmanship.
The Chief Engineer of the Digital-Precise system has decades of experience in the design of spacecraft instrumentation and sensing systems where a single miss-placed photon of light or a single unwanted energetic particle can cause interference and even damage.
By applying this extreme state-of-the-art knowledge to the Digital-Precise product, an exceptional connectivity solution has emerged.
Belden 8281F Precision Coaxial Cable
Digital-Precise uses Belden 8281F, 75 ohm cable. This cable is designed for precision audio and video applications. This cable has many engineering specifications, features and innovations to make it the “cable of choice” for Digital-Precise.
The center conductor of the Belden 8281F is a finely stranded, 7x29 (7 strands of AWG 29 each) conductor that yields a 22 AWG (American Wire Gauge) overall. This provides good physical flexibility and ruggedness while maintaining low electrical signal loss and thereby providing excellent SNR (signal to noise ratio).
The outer conductor (shield) of this cable is double shielded configuration. This provides outstanding “optical coverage”. Optical coverage refers-to the percentage of optical “window space” when viewing the braid from an orthogonal perspective (90 degree angle). Good optical coverage is a crucial specification for low susceptibility to interfering signals. Each of the conductors of the Belden 8281F has an impressive 98% optical coverage specification.
Belden uses the venerable Polyethylene material for the dielectric insulation. In addition to offering very high baseband isolation, this is the major contributor to the excellent velocity propagation factor of 66% and the very, very low group delay specification of, 1.54 nano-seconds per foot!
This cable is 100% sweep tested at the Belden factory over a range of 5 MHz to 850 MHz. This upper frequency is approximately 1000 times greater than the digital sampling frequency! This is an important feature for several reasons. Firstly it underscores the impressive native bandwidth of this cable. Secondly, it is an effective test for detecting possible manufacturing defects in the center conductor, the braided outer conductor (shield) and the all-important dielectric.
The Belden 8281F exhibits very low return loss in the 217 MHz to 830 MHz region. This return loss figure is an excellent 23 db. This contributes heavily to the much-desired sharp/precise digital signal rise times that result in optimal clock recovery in the receiver.
Scientific Conversions Transformer
Digital-Precise uses the Scientific Conversions SC9x7 Series Transformers. These transformers were carefully selected as the premier choice for achieving overall Digital-Precise performance.
Scientific Conversions designed these transformers for use with various popular transmitters, receivers and transceivers, such as: AKM, Crystal, Motorola, TI/Burr-Brown, Wolfson, Yamaha for operational sample rates up to 96 - 192 kHz.
These parts have a very low primary-to-secondary inter-winding capacitance (5.5 pico farad max.) which is a result of an innovative implementation of the venerable Faraday shield. This performance feature of the Scientific Conversions transformer directly supports the Digital-Precise’s low susceptibility to both radiated and conducted interference. This feature also provides greatly decreased jitter and thereby low inter-symbol interference in the face of the many interference sources such as: high speed DSP and microprocessor clocks, RF noise, switching power supplies, cross-talk from adjacent cables, etc.
The rise-time of these transformers is an astoundingly low: 3 nano-seconds.
Encapsulation
The Digital-Precise design would not be complete if the carefully designed and precision crafted system were left exposed to the environmental influences of the physical world: temperature, humidity, contaminants, ultra-violet radiation, free oxygen, etc. The Digital-Precise unit is encapsulated in a hard epoxy resin to protect it for years to come.
Sujet: câble digital Noble Electronics Symétrique 
Dim 16 Sep - 14:52
