Weiss Engineering Ltd. Florastrasse 42, 8610 Uster, Switzerland www.weiss-highend.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT INTRODUCTION Dear Customer Congratulations on your purchase of the JASON CD Transport and welcome to the family of Weiss equipment owners! The JASON is the result of an intensive research and development process. Research was conducted both in analog and digital circuit design, as well as in signal processing algorithm specification. On the following pages I will introduce you to our views on high quality audio processing.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT TABLE OF CONTENTS 4 A short history of Weiss Engineering 5 Our mission and product philosophy 6 Advanced digital and analog audio concepts explained 14 Page: 6 Jitter Suppression, Clocking 8 Upsampling, Oversampling and Sampling Rate Conversion in General 11 Reconstruction Filters 12 Analog Output Stages 12 Dithering The JASON CD Transport 3 14 Features 17 Operation 21 Technical Data 22 Contact Date: 03/13 /dw
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT A SHORT HISTORY OF WEISS ENGINEERING After studying electrical engineering, Daniel Weiss joined the Willi Studer (Studer - Revox) company in Switzerland. His work included the design of a sampling frequency converter and of digital signal processing electronics for digital audio recorders. In 1985, Mr. Weiss founded the company Weiss Engineering Ltd.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT OUR MISSION AND PRODUCT PHILOSOPHY The wealth of experience we have gained in over 20 years of designing products for top Mastering Engineers, we now apply to the design of outstanding High-End Hi-Fi products. Our mission is to create equipment which becomes classic right from the outset; - outstanding in sonics and design.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT ADVANCED DIGITAL AND ANALOG AUDIO CONCEPTS EXPLAINED Jitter Suppression and Clocking What is jitter and how does it affect audio quality? In the audio field the term jitter designates a timing uncertainty of digital clock signals. E.g. in an Analog to Digital Converter (A/D) the analog signal is sampled (measured) at regular time intervals; in the case of a CD, 44100 times a second or every 22.675737.. microseconds.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT Yes, those are in essence sampling rate converters, however in a well designed system these converters employ a synchronous design, where jitter does not play any role. Of course a conversion between 96kHz and 44.1kHz as in the example above, can be done in a synchronous manner as well.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT In the MEDEA we employ a two stage PLL circuitry which very effectively suppresses jitter. A common problem with most PLLs used in audio circuitry is that they suppress jitter only for higher frequencies. Jitter frequencies which are low (e.g. below 1kHz or so) are often only marginally suppressed. It has been shown that low frequency jitter can have a large influence on the audio quality though.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT A physical law states that in order to represent any given analog signal in the digital domain, one has to sample that signal with at least twice the frequency of the highest frequency contained in the analog signal. If this law is violated so called aliasing components are generated which are perceived as a very nasty kind of distortion.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT ringing due to the high steepness. In the early days of digital audio these side effects have been recognized as beeing one of the main culprits for digital audio to sound bad. So engineers looked for ways to enhance those filters. They can’t be eliminated because we are talking laws of physics here.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT Reconstruction Filters Reconstruction filters have been mentioned in the "Upsampling, Oversampling and Sampling Rate Conversion in General" paragraph above. If you have read that paragraph you know what the purpose of the reconstruction filter is. The main point about this analog filter is that its frequency response should be as smooth and flat as possible in order to have a virtually linear phase response. The MEDEA employs a 3rd order filter for that purpose.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT Dithering You have probably not heard the term dithering in conjunction with audio. Actually it is a term widely used in the professional audio realm but not so much in the High-End Hi-Fi market. What is dithering? Suppose a digital recording has been made with a 24 bit A/D converter and a 24 bit recorder. Now this recording should be transferred to a CD which has just 16 bits per sample, as you know.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT I hope these excursions into the theory and practice of audio engineering have been useful for you. If you would like to dive further into those issues I recommend to visit the website of Mr. Bob Katz, a renowned Mastering Engineer and a Weiss Engineering customer. He publishes articles on Dithering and Jitter and many other topics at http://www.digido.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT THE JASON CD TRANSPORT Features Transport: The Jason uses the renowned Philips CDPRO2M transport as its core unit. Synchronization: An internal high precision / low jitter clock generator generates all clocking signals, including those necessary for the CDPRO2M transport. Digital Signal Processing: The 44.1kHz / 16 Bit signal coming from the CDPRO2M can optionally be upsampled to 88.2 kHz or 176.4 kHz.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT There is a "D/A Converter Enhancement" mode (DAC+ on the remote control unit). This mode helps to enhance the sonic quality of D/A converters connected to the JASON. DAC+ uses spread spectrum technology. Try the DAC+ mode and leave it on or off as per your preference. With excellent D/A converters you should not be able to hear a difference between DAC+ mode on or off.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT Frontpanel elements: • Five switches for skip backward, skip forward, stop, play/pause and lid open/close. • A high resolution graphical display. • A power switch. Backpanel elements from left to right: • USB connector for software download (for future software upgrades). • RCA and Toslink connector for fixed sampling rate 44.1kHz output. • RCA, ST optical, BNC, XLR connectors for single wire 44.1 / 88.2 / 176.4 kHz output.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT Operation Unpacking and setup of the JASON Carefully unpack the JASON. The following items should be enclosed: • The JASON CD Transport unit • A Remote Control unit • A product registration card • This Owners Manual • A Certificate of Guarantee The JASON should be placed horizontally on a plane surface. Make sure that there is enough space above the unit such that the lid can open freely.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT Output Connection Depending on the D/A Converter you connect, you need to set up the JASON. First you need to know some technical information about your D/A converter, namely the sampling rates it is able to operate at, the wordlength it is capable to accept at its input and the kind of connectors it has. Here is a guide for all kinds of D/A variants. The numbers refer to the numbers printed on the backpanel of the JASON to designate the output connectors.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT • D/A operates up to 88.2kHz, not at 176.4: Use ouput 1, 2, 3, 4 or 5. Output 1 is the dual wire output. Use this only if your D/A converter is designed to accept a dual wire signal. On the remote control set the sampling rate to 44.1kHz or 88.2kHz and the output wordlength to the maximum number of bits your D/A converter is capable to convert. E.g. if it is designated to be a "20 Bit converter" then set the output wordlength to 20 bits.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT The Remote Control The JASON remote control sports the standard CD transport controls and in addition a few controls unique to the JASON CD transport. To access the functions printed below the keys first press and hold the ALT key on the lower left and then press the second key. Note that the keypad can be locked / unlocked. For locking press ALT / mute. For unlocking press ALT / bright+. Also see the back of the remote control.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT Technical Data Digital Outputs: Output Connector type Format Available sampling rate(s) Available wordlengths 1 (2) XLR AES/EBU dual wire 88.2 / 176.4 *) 16 / 20 / 24 bits 2 XLR AES/EBU single wire 44.1 / 88.2 / 176.4 16 / 20 / 24 bits 3 BNC AES/EBU single wire 44.1 / 88.2 / 176.4 16 / 20 / 24 bits 4 RCA AES/EBU single wire 44.1 / 88.2 / 176.4 16 / 20 / 24 bits 5 ST optical AES/EBU single wire 44.1 / 88.2 / 176.
OWNERS MANUAL FOR WEISS JASON CD TRANSPORT CONTACT For any questions, suggestions etc. feel free to contact us at: Weiss Engineering Ltd. Florastrasse 42 8610 Uster Switzerland Phone: +41 44 940 20 06 Fax: +41 44 940 22 14 Email: weiss@weiss.ch Web: http://www.weiss-highend.com http://www.weiss.
