EC-2 96kHz Sample Rate Upgrade A/D and D/A Converter Cards for the ADAT HD24 Hard Disk Recorder OWNER’S MANUAL VERSION 1.0 APPLIES TO ADAT HD24 SOFTWARE VERSION 1.
EC-2 96kHz A/D/D/A upgrade • appendix A © 2002 Alesis. All rights reserved. Reproduction in whole or in part is prohibited. Change Without Notice.
appendix A EC-2 96kHz Upgrade Cards This document covers only those aspects unique to the EC-2 cards and should be kept with the HD24 manual. Table of Contents Important Safety Instructions ................................ 2 Safety symbols used in this product ....................... 2 CE Declaration of Conformity................................ 2 About the EC-2..................................................... 2 Installing the EC-2 into the HD24........................... 3 Using the EC-2 ............
EC-2 96kHz A/D/D/A upgrade • appendix A Important Safety Instructions Safety symbols used in this product This symbol alerts the user that there are important operating and maintenance instructions in the literature accompanying this unit. This symbol warns the user of uninsulated voltage within the unit that can cause dangerous electric shocks. About the EC-2 The EC-2 is an optional 96kHz sampling rate analog hardware upgrade designed exclusively for the Alesis ADAT HD24.
appendix A • EC-2 96kHz A/D/D/A upgrade Installing the EC-2 into the HD24 Precautions The EC-2 boards should only be installed by a dealer or trained technician. End users should only attempt installation if they have experience with this type of procedure. If any of the following instructions are not clear to you, please have a dealer or trained technician install it for you. Improper installation by the end user may damage the boards and/or your HD24 and may void your warranty.
EC-2 96kHz A/D/D/A upgrade • appendix A Prepare to install: Remove the existing converter PCBs and cables: 1 . Disconnect the HD24’s AC power cable, and make sure you are working on a clean, flat, hard surface. Ground yourself by touching a grounded metal object. An anti-static workstation with anti-static mat and wrist strap is highly recommended. 3. Hazardous voltages are present within the chassis. Do not remove the top panel without first unplugging the unit from AC power! 2.
appendix A • EC-2 96kHz A/D/D/A upgrade Install the new EC-2 PCBs 7. Find the daughterboard in the EC-2 package: it has two 26-pin flexible cables attached to it. Insert the ribbon connector labeled “J4 TO MAIN PCB” on the daughterboard into the 26pin header labeled on the main PCB as “J15 TO A/D PCB”. 8 . Insert the ribbon connector labeled “J3 TO MAIN PCB” on the daughterboard into the 26pin header labeled on the main PCB as “J14 TO D/A PCB”.
EC-2 96kHz A/D/D/A upgrade • appendix A Connect the PCBs 13. Connect the daughterboard to the Input and Output PCBs: Line up the connectors to the bottom (D/A) and top (A/D) PCBs, make sure all the pins line up, then gently push the daughterboard to the rear of the HD24 using the plastic ribbon cable headers as pressure points, making a connection between all three PCBs. The connectors will only line up in one orientation. Verify that there are no pins unconnected or exposed. 14.
appendix A • EC-2 96kHz A/D/D/A upgrade Synchronizing at high sample rates: To record more than 12 tracks in the high sample rate mode, simply synchronize two HD24/EC-2 units together by linking them with an ADAT Sync cable (see page 24 of the HD24 manual). Up to five HD24s may be synchronized this way, allowing high-sample rate systems of up to 60 tracks.
EC-2 96kHz A/D/D/A upgrade • appendix A About the EC-2’s audio performance An HD24 with the EC-2 upgrade has audio performance far superior to that of any analog recorder, and a wider dynamic range than most input and output devices that may be connected to it. Here’s why: The converter defines the sound The first and last steps in digital recording—the conversion from analog to digital, then back again—define the audio quality of the digital recording process.
appendix A • EC-2 96kHz A/D/D/A upgrade aliasing, the steeper the filter, the better. Some converters boasted 10 th-order (-60 dB per octave) filters. For comparison, most loudspeaker crossovers have 3rd or 4th-order filters (-18 or –24 dB per octave). The problem is similar on the output side—the 44.
EC-2 96kHz A/D/D/A upgrade • appendix A Extending the frequency range of other studio equipment Even though an ADAT HD24 equipped with the EC-2 upgrade gives you the capability of recording audio beyond 40 kHz, many other elements of your studio may need to be upgraded to truly take advantage of this capability. Most studio equipment was designed to meet a 20-20 kHz spec, not the 44 kHz range that the EC-2 can record.
appendix A • EC-2 96kHz A/D/D/A upgrade Using the HD24/EC-2 with computer workstations and digital mixers Because the EC-2 upgrade provides 24 high quality inputs and outputs, it can be used as an external converter to extend the number of analog inputs and outputs of any computer workstations and digital mixers that feature an ADAT Optical interface. When using it as an A/D converter, press the ALL INPUT button with INPUT SELECT set to ANALOG; when using it as a D/A converter, set INPUT SELECT to DIGITAL.
EC-2 96kHz A/D/D/A upgrade • appendix A Using the HD24/EC-2 with the Alesis AI-4 AES/EBU Interface The Alesis AI-4 AES/EBU Digital Audio Interface is a single-rack space unit available from your Alesis dealer that lets you connect ADAT Optical input and output signals to industry-standard AES/EBU digital signals, eight channels at a time. The AI-4 is designed to handle standard operation, as well as high sample rates (88.2/96kHz).
Specifications For the Alesis HD24 with EC-2 96 kHz Sample Rate Upgrade A/D and D/A Converter Boards: AUDIO INPUT Input Connectors: Nominal Input Level: Maximum Input Level: Input impedance: A/D converter: Analog filter: Latency (analog in to digital out): 24 balanced 1/4" TRS jacks +4 dBu (1.23 VRMS) = -15 dBFS +19 dBu (6.9 VRMS) = -0 dBFS 10 kΩ AKM 5393 2nd-order Butterworth filter w. 96 kHz corner frequency Approximately 45 samples (<1 ms.