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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 1.05 AND ABOVE
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EC-2 96kHz A/D/D/A upgrade • appendix A © 2002 Alesis. All rights reserved. Reproduction in whole or in part is prohibited. Specifications Subject To Change Without Notice. 7-51-0107-A 6/2002 EC-2 Manual
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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 ........
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EC-2 96kHz A/D/D/A upgrade • appendix A Important Safety Instructions About the EC-2 The EC-2 is an optional 96kHz sampling rate analog hardware upgrade designed exclusively for the Safety symbols used in this Alesis ADAT HD24. It provides 24 simultaneous product channels of balanced +4 dBu analog audio inputs and outputs via 48 1/4” TRS type jacks. The EC-2 is installed directly inside the HD24’s rear panel, in place of the original A/D and D/A boards, for This symbol alerts the user that th
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appendix A • EC-2 96kHz A/D/D/A upgrade Installing the EC-2 into the HD24 Overview Precautions In the HD24, the conversion between analog and digital signals takes place on two PCBs (printed circuit boards) that are mounted directly to the The EC-2 boards should only be installed by a input (A/D) and output (D/A) connectors that poke dealer or trained technician. End users through the back panel. In a “stock” HD24 without should only attempt installation if they have 96 kHz sampling capabili
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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 3. Locate the existing DC power cable. This cable surface. Ground yourself by touching a has several thick red, orange, yellow, black, and grounded metal object. An anti-static blue wires bundled together. Pinch the tab lock workstation with anti-static mat and wrist holding the white connector
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appendix A • EC-2 96kHz A/D/D/A upgrade Install the new EC-2 PCBs NOTE: The Analog Input and Analog Output PCBs look very similar. Verify that you have 7. Find the daughterboard in the EC-2 package: it the correct PCB by looking for the part number has two 26-pin flexible cables attached to it. and part name in the text in the corner of the Insert the ribbon connector labeled “J4 TO MAIN PCB” on the daughterboard into the 26- PCB. pin header labeled on the main PCB as “J15 TO A/D PCB”. 11. Pl
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EC-2 96kHz A/D/D/A upgrade • appendix A Using the EC-2 Connect the PCBs 13. Connect the daughterboard to the Input and For important information about high-resolution Output PCBs: Line up the connectors to the operation of the HD24, see Chapter 7 of your bottom (D/A) and top (A/D) PCBs, make sure ADAT HD24 owner’s manual (page 65). 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, About 96kHz/88.2kHz Sampl
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appendix A • EC-2 96kHz A/D/D/A upgrade Inputs and Outputs Synchronizing at high sample rates: The inputs and outputs of the HD24/EC-2 are the To record more than 12 tracks in the high sample same basic type as on a “stock” HD24: balanced rate mode, simply synchronize two HD24/EC-2 1/4” TRS jacks with a nominal +4 dBu level units together by linking them with an ADAT Sync corresponding to –15 dBFS on the HD24’s meter. In cable (see page 24 of the HD24 manual). Up to five most installations, t
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EC-2 96kHz A/D/D/A upgrade • appendix A About the EC-2’s audio When to use 88.2/96 kHz performance Why 44.1/48 kHz? An HD24 with the EC-2 upgrade has audio Many engineers believe that the sampling rates that performance far superior to that of any analog have been used up to now are less than ideal. The recorder, and a wider dynamic range than most industry-standard sample rates were chosen at a input and output devices that may be connected to time when digital storage was much more it. Here’
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appendix A • EC-2 96kHz A/D/D/A upgrade aliasing, the steeper the filter, the better. Some However, a digital filter with perfectly flat phase th converters boasted 10 -order (-60 dB per octave) response still filters out frequencies above 20 or 22 filters. For comparison, most loudspeaker kHz. Good analog tape recorders are capable of rd th crossovers have 3 or 4 -order filters (-18 or –24 dB recording beyond 30 kHz. And there are those who per octave). believe that higher frequencies, whil
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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 If you’ve done all the above, and confirmed your EC-2 upgrade gives you the capability of recording studio’s capability of reproducing the full range of audio beyond 40 kHz, many other elements of your frequencies the HD24/EC-2 can record, you now studio may need to be upgraded to truly take have a truly state-of-the-art studio that’s capable of advantage of
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appendix A • EC-2 96kHz A/D/D/A upgrade Using the HD24/EC-2 with computer workstations and digital mixers Latency Because the EC-2 upgrade provides 24 high quality Every digital conversion requires a certain amount inputs and outputs, it can be used as an external of time, although the time delay involved is usually converter to extend the number of analog inputs less than the time it takes sound to travel one foot and outputs of any computer workstations and through the air. However, if you ha
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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). With the AI-4 you can: • Export tracks from the HD24 to masterin
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Specifications For the Alesis HD24 with EC-2 96 kHz Sample Rate Upgrade A/D and D/A Converter Boards: AUDIO INPUT Input Connectors: 24 balanced 1/4" TRS jacks Nominal Input Level: +4 dBu (1.23 V ) = -15 dBFS RMS Maximum Input Level: +19 dBu (6.9 V ) = -0 dBFS RMS Input impedance: 10 k Ω A/D converter: AKM 5393 nd Analog filter: 2 -order Butterworth filter w. 96 kHz corner frequency Latency (analog in to digital out): Approximately 45 samples (<1 ms. @ 48 kHz) AUDIO OUTPUT Output Connectors: 24 b
