Alesis has been steadily improving ADATs since their first introduction. Later versions include better transport action, advanced copy features, 20 bit recording, and SMPTE synchronization. this note covers the basic operation of the original version.
ADATs use S-VHS tape cassettes-- they are a bit fussy, so use only premium S-VHS tape. There is an Ampex tape made expressly for the ADAT, but most brand name tapes will do. A 120 minute tape will give you 40 minutes of recording on the ADAT. Although you can use longer tapes with some models of ADAT, don't reccommend you put more than one project on a single tape- rewinding is hard on the data, and when the tape gets eaten you don't want to loose too much work. If possible, you should use a second ADAT and back up your important tapes.
A new tape must be formatted before use. YOU SHOULD ALWAYS FORMAT THE ENTIRE TAPE IN ONE PASS. An old tape may be reformatted to erase it.
You can record tracks during the format process, if you enable the track before you press FORMAT. You cannot punch out, and STOP will end the formatting process.
The large button under a track's level display is the record enable. Press it and the record LED will flash. If AUTO INPUT and ALL INPUT are off, input levels for enabled tracks will be displayed. Note that the ADAT does not have any level controls. Signals must be adjusted at the mixer or source.
Tracks will not begin recording until both the PLAY and RECORD buttons are pressed together. Once tracks are recording, you cannot turn them off or on with the enable buttons.
If you hold PLAY and press STOP, recording will cease but play will continue.
There are 4 input monitor modes on the ADAT.
To hear the recorded signal up to the punch point, follow these steps:
This sets Auto Input to mode 2, where input monitoring only occurs during recording. Return to normal operation of AUTO INPUT by repeating this procedure. (The display should say In.)
Locate points are set by holding the SET LOCATE button and pressing one of the three LOCATE buttons. Note that the Locate 0 button will redefine the current point on the tape to display as 00.00. This will not change the points found by Locate 1 or Locate 2. Once points are set, the following functions are available:
If you HOLD the Play and REWIND buttons, the ADAT will cue back at three times normal speed. When you release the REWIND button play will begin.
To change the pitch, press the PITCH UP or PITCH DOWN buttons. These must be held for a bit. The pitch change will be displayed in cents. The LEDs in the button will stay lit when the pitch is odd
Pitch changes affect both tape speed and sample rate, so tempo will change with the pitch. The time display reflects the time elapsed at normal speed. To get pitch back to normal, hold both buttons down.
The ADAT mechanism is borrowed from a VCR. If you have used a VCR, you have probably noticed that they take forever to engage and start recording. The ADAT avoids this delay (somewhat) by going into a pause mode when you press stop. The heads are still spinning against the tape wearing out both. If you don't play for a little while the ADAT goes into a real stop mode; then it takes a while to get going again. When the head is disengaged like this, the stop led flashes. You can re-engage by pressing stop. If you press stop twice after playing, the head disengages immediately.
ADATs seem to be very reliable. It was originally thought that the heads would wear out quickly, but this does not seem to be happening. There is a rubber roller inside that wears pretty fast, but otherwise, most users are happy.
When two machines are linked for multitrack operation, some operations are rather slow. This is complicated by the fact that the original release of ADAT was buggy, and there have been several software revisions. The software on both machines should match for best performance. (Hard to imagine that major machines like tape recorders should have software, but they do. It's wired in, however, and takes a technician to change programs.) Press Set Locate and Fast Forward to read the software version.
The error rate is indicated by a dot in the lower right corner of the display. Head cleaning should be done by a qualified technician, but it can be done using the 3M "Black Watch" cleaning cassette, which is not abrasive and uses no fluids. (If you really want to learn to clean your own ADAT and DAT heads, make friends with a VCR technician, who can show you how. There are also books on the subject. It's not all that hard, but of course you kiss your warrantee good-by.)
The original ADAT uses 7 segment LEDs for display. These give rather enigmatic notice of certain situations:
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