User manual ALESIS EC2

[. . . ] 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 EC-2 96kHz A/D/D/A upgrade · appendix A © 2002 Alesis. 7-51-0107-A 6/2002 Specifications Subject To EC-2 Manual 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Using the EC-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Extending the frequency range of other studio equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] 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". The headers on the main PCB sit near the back center, where the old input/output PCBs used to plug in. The red side of each cable should face the right of the HD24 (closest to the fan). Verify that the cables don't have any twists in them and that there are no unconnected or exposed pins on the headers. Lay the daughterboard gently on the PCBs at the rear of the hard drive cages until the Analog Input and Analog Output PCBs are installed. Remove the nuts and washers from the 1/4" connectors on the new Analog Output (D/A) PCB. HD24 with EC-2 installed Daughterboard PCB 1 Analog In A/D PCB 2 3 4 5 6 Analog Out D/A PCB New DC power cable EC-2 Manual A-5 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. Put the remainder of the washers and nuts on the jacks of the input and output connectors and tighten them all down (total 48 jacks). For more on operation of the ADAT Optical port, see page 66 of the HD24 manual. · When using an HD24/EC-2 at the standard 44. 1kHz or 48kHz sampling rates, you will still be able to record and play back all 24 tracks. The only difference from the original boards will be improved audio performance, due to the higher quality converters and analog circuitry of the EC-2. A-6 EC-2 Manual 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. Inputs and Outputs The inputs and outputs of the HD24/EC-2 are the same basic type as on a "stock" HD24: balanced 1/4" TRS jacks with a nominal +4 dBu level corresponding to ­15 dBFS on the HD24's meter. In most installations, there will be no difference in meter readings or levels after you install the EC-2. However, there is a slight difference in the balancing circuitry that may affect some installations. The EC-2 features true differential inputs and outputs, with dual drivers on each output instead of the more common (and less expensive) "impedance balanced" (sometimes called "ground compensated") method of balancing the outputs found on most audio gear (and on the original HD24 boards). As a result, if you plug the output of the EC-2 into an unbalanced input, the nominal output will be ­2 dBu, 6 dB less than if the EC-2 was seeing a true balanced load. This is normal operation and has no effect on the final quality of the sound. . . it only reduces the readings on the console's tape return meters. To avoid this 6 dB loss, simply plug the outputs of the HD24/EC-2 into balanced inputs on the console. Synchronizing two HD24s at different sample rates: When synchronizing multiple HD24s (or an HD24 with tape-based ADATs) together, it is possible to have an HD24 record and play back a high sample rate Song, while other machines play back a standard sample rate Song. In this case, the sample rates must be even multiples of each other (44. 1 with 88. 2 or 48 with 96 kHz). For example, one HD24 can be running with 24 tracks of instrumental tracks at 48 kHz while a second HD24 records and plays back 12 tracks of vocals and leads at 96 kHz, for a total of 36 tracks simultaneously. Depending on the software version of your HD24, a warning message may appear or the sample rate indicator may flash indicating the mismatch in rates, but this will not affect operation. EC-2 Manual A-7 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: When to use 88. 2/96 kHz Why 44. 1/48 kHz? Many engineers believe that the sampling rates that have been used up to now are less than ideal. The industry-standard sample rates were chosen at a time when digital storage was much more expensive than it is today. [. . . ] A soft-dome tweeter trying to reproduce 30-40 kHz often goes into irregular modes that may, oddly, sound "good" to a listener, but they're not really playing back what was recorded. If you've done all the above, and confirmed your studio's capability of reproducing the full range of frequencies the HD24/EC-2 can record, you now have a truly state-of-the-art studio that's capable of mastering audiophile-quality DVDs and SACDs. Though the extra octave of high end may not be audible to the majority of listeners (or even to you, especially if you've been listening to loud music for too many years), you can be assured that what you're recording will stand the test of time, for all listeners. Good luck and thank you for using the ADAT HD24 with the EC-2 96 kHz Upgrade! · · · A-10 EC-2 Manual 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. [. . . ]