Tascam DA98

It started at 88, dropped to 38, now rises to 98... no, it's not the chart performance of the new Spice Girls album, but Tascam's rather strange way of numbering the models in their respected DA series of digital multitrack recorders. Hugh Robjohns checks out the new flagship in the range.

Digital Tape Recording System (DTRS) machines are the most common type of digital multitracks found in broadcast or post‑production environments. Tascam's original DTRS machine, the DA88, was joined by the slightly simplified but more cost‑effective DA38 about two years ago, and now, with the launch of the DA98, the Tascam DTRS family consists of three machines.

Despite the obvious move towards hard disk recording and 20‑bit (or more) resolution, Tascam have continued to develop their DTRS machines. The DA38 was the result of making the technology more cost‑effective in an attempt to reach the lower budget sectors of the market, and the DA98 is the result of discussions with 'high‑end' users (mainly in the post‑production industry) about what they wanted from the DA88. As a result, the flagship DA98 is effectively an updated DA88 with all the bells and whistles built in.

Hardware

You could not mistake the DA98 for anything other than a member of the DA family, as, apart from the new backlit display panel, its control panel is superficially identical to the other DA machines. The bargraph metering is on the right‑hand side, the transport controls are laid out beneath the tape slot and even the unusual arrangement of the Play and Record buttons (they're adjacent) is the same.

The tape transport mechanism in the new machine is a derivative of that in the DA38, which was itself an evolution of the original and extremely reliable DA88 mechanism. Much of the DA98's electronics has evolved too, taking advantage of new integrated circuits.

From the user's point of view, one of the most significant improvements between the new machine and the original DA88 workhorse is that timecode generation and chase synchronisation are provided as a built‑in facility (it was an optional extra on the DA88 and not available at all on the DA38).

Another significant improvement which the DA98 exhibits over its forebears is that its 9‑pin remote control has been updated to conform fully with the ubiquitous Sony P2 protocol (as opposed to Tascam's own version of RS422 control), although the machine can also emulate a variety of 'standard' 9‑pin machines, as well as adopting the original control format for backwards compatibility.

It is very hard to think of anything that has been left out of the DA98 — it really does appear to be a DTRS machine built to meet the needs of the most demanding professional.

Flagship Features

There is only so much a digital 8‑track machine can do, and within certain parameters, any digital multitrack is much like another. However, the DA98 has some unique features which could make life considerably easier. Probably the most significant of these is the inclusion of proper off‑tape confidence monitoring, complete with an obvious but comforting 240ms off‑tape delay! There is a comprehensive tape/source selection system, with automatic switching functions dependent on transport status just like an analogue multitrack, although there are a few restrictions on recording when using the off‑tape monitoring mode, of which more later.

I have already mentioned the built‑in synchronisation system, which appears to work extremely efficiently. Obviously highly optimised to the mechanics of the machine, the DA98's chase and lock‑up times are very fast. The timecode chase operations are very sophisticated, with a continuous re‑chase option (where the machine tries to accurately follow the incoming timecode, complete with its potential speed variations), or a 'synchronise and run‑free' mode where it locates to the right place and then locks to a stable video signal or wordclock.

Another useful addition to the feature list is an internal signal routing matrix which allows full mapping between either the digital TDIF or analogue inputs and any of the eight recording tracks. This routing matrix also permits internal track copying to move audio from one track to another, but the system is not capable of combining the audio from multiple tracks, so you can't use it to bounce down.

To take account of the growing number of affordable digital desks, Tascam have equipped the DA98 with an internal dithering system so that signals presented on the TDIF inputs with greater than 16‑bit resolution can be sensibly reduced to the 16 bits the tape format is capable of storing. It is a shame that Tascam didn't see fit to incorporate a mode for track‑sharing, to allow 4‑ or 5‑track recording with 24‑bit resolution, as there does seem to be growing interest in this kind of operation, and there are already a number of third‑party interfaces on the market to allow exactly this.

Of particular interest to music recording users is the DA98's ability to slip tracks relative to one another by up to 150 milliseconds in fine increments. This feature can be used to compensate for the different arrival times of sound when using spaced microphones (correcting for distances of up to 50 metres).

Tascam have discarded ‑10dBV analogue connections completely from the DA98, as they clearly see this machine only serving in professional environments. Balanced analogue I/Os are via 'D'‑sub connectors at a nominal +4dBu level and the same wiring convention has been used as other DTRS machines. Recording headroom within the machine is determined through the operating software and the machine can be set up such that a nominal +4dBu reference level is aligned to either the 'Tascam Operating Level' (‑16dBFS), the EBU level (‑18dBFS), or the SMPTE level (‑20dBFS). In practice, this means that the machine can accommodate peak analogue signal levels of between +20dBu and +24dBu respectively.

Two new timecode‑striping modes on the DA98 — ABS13 and ABS23 — effectively automate the process of providing a timecode pre‑roll and starting each recording on a memorable timecode point. The first mode provides up to 10 minutes of recording (with a 3‑minute pre‑roll), and the second allows up to 20 minutes recording. Taking the ABS13 mode as an example, once activated it will start the tape with a timecode of, say, 00:57:00:00, with the first programme material going down at 01:00:00:00. Ten minutes later, the timecode is forced to 01:57:00:00 and the cycle repeated, and each subsequent programme item starts at the top of the next hour (in terms of timecode values). The ABS time on the tape is continuous and sequential from the start of the tape, of course. This facility has been added primarily for the convenience of film dubbing houses, to suit typical film reel lengths, but would also be very handy for recording and locating several commercials or even music recordings within the same tape.

Virtually all of the DA98's settings are made through the new LCD panel, and there are no controls or switches on the rear panel at all. The software control on the LCD is navigated with simple cursor keys and an Enter/Escape system which are reasonably intuitive to negotiate. As most users tend to operate this kind of machine in a repetitive way, and only use a few different setups, the 10 most commonly used menu functions can be assigned to instant access 'function‑keys'. These can also be used as locator memories to supplement the familiar 2‑point auto‑locator with its A/B repeat functions. Best of all, they can also be used as numeric keys for data entry of things like timecode values — something which previously could only be done through the large remote controller panel.

Knobs And Twiddly Bits

The DA98's rear panel is a forest of connectors, but they are organised in five 'levels' on the left‑hand side of the panel, with a standard IEC mains lead in the bottom right‑hand corner.

The Tascam DA98 rear panel features most pro connectors you'll need.

Balanced analogue I/Os at the +4dBu nominal level are arranged on the lower two levels using the Tascam standard 25‑way 'D'‑sub connectors. The middle row of the five contains multi‑pin interfaces for the meter bridge, the TDIF I/O, and the Sync in/out connectors which provide sample‑accurate locking with other DA‑family machines.

The top row of interfaces provides timecode in and out (on XLRs at last), video in and through (with an automatic 75Ω termination function), and wordsync in, out and through (also with auto‑termination). The video and wordsync connectors employ BNCs. Immediately below these facilities are an RS422 interface (now conforming to the Sony protocol more fully), the standard set of three MIDI sockets, and a parallel machine control port.

The 4‑line, 20‑character backlit LCD panel immediately to the right of the tape time display is probably the most striking feature of the DA98. Other than that though, any DA88 user would feel very comfortable with the controls on this machine, as most of them are identical to its siblings, or are very intuitive. For example, the new row of buttons beneath the track‑arming keys, which control the input monitoring status on a track‑by‑track basis, hardly require rocket scientists to figure them out. On the extreme left‑hand side there are three small buttons and indicators which provide selection of the Digital Inputs, activate the Chase Sync mode, and engage the Confidence (off‑tape) Monitoring facility.

Around the timer display, there are a lot more indicators than in the other DA models, and in addition to the usual LEDs, status indicators are provided for the (new) track copy mode, pull‑up/down status for drop‑frame timecode synchronisation, and for the (new) track delay mode.

I mentioned earlier the inclusion of 'Function Keys' and these are alternative uses for 10 of the keys directly below the time display (those labelled RHSL, Auto Punch, Memo 1, and so on). There is labelling below their main functions to indicate their enhanced roles. These Function Key modes are accessed by pressing the 'Shift' button (adjacent to the cursor keys) and three possibilities exist for these keys. They can be used as quick‑access menu keys (ie. providing direct entry to user‑determined menu pages), additional locate position memories, or a numeric keypad for data entry.

There are a total of 12 menu pages and they are identified as pages 0 to 9, E and F. If you happen to remember the identification address of a specific menu, it can be located by selecting the appropriate number or letter from the 'Home' menu at the top of the software tree. The cursor keys are used to navigate around a selected menu page and to identify the particular parameter you wish to alter. Hitting the Enter key allows the parameter to be edited and, again, the cursor keys are used to increment or decrement the value as necessary.

The first menu (Group 0) provides functions like track delays, track copying, locate memory stores, locate pre‑roll time, and varispeed settings. Group 1 has settings for in and out point times (for drop‑in rehearsals and recordings), pre‑ and post‑rolls (ie. playback window before and after the drop‑in), drop‑in crossfade duration, and dither type.

Group 2 covers things like TDIF input word lengths, signal reference levels and the internal oscillator settings, while Groups 3 and 4 are involved with machine ID flags in multi‑machine systems, time reference sources, control protocols, machine offsets, and timecode chasing. Group 5 relates to the comprehensive timecode features such as frame rates, video resolving, and timecode sources, while Group 6 is concerned with RS422 operation, including machine emulation, record delays, and track mapping from edit controllers.

All the MIDI functions and the operation of the 'Function Key' modes are set up in Group 7, Group 8 sets the timecode generator, and Group 9 controls an automatic head cleaning system and provides off‑tape error‑rates. The last two menus, E and F, provide displays of various kinds of data, such as information from the various timecode sources, and display of software versions. Obviously, a great deal of the machine's functionality can be customised, and so Tascam have provided three user memories, plus a factory preset memory.

Off‑Tape Monitoring

The monitoring arrangements on the DA98 are very complicated from a technical standpoint, but Tascam have been able to make them extremely intuitive to operate. Modes such as 'All Input' and 'Input Monitor' will be very familiar, but there are also automatic switching facilities called 'Auto Mon' and 'Shtl Mon'. The former forces the monitoring to off‑tape on any armed tracks when in Play mode, but input when in record or stopped. The 'Shtl Mon' mode only works when 'Auto Mon' is enabled and simply allows the input signal to be heard on armed tracks during tape shuttling operations (with this mode off, you would hear the replayed track chattering as it spools).

The new confidence monitoring mode is switchable on a track‑by‑track basis using the Input Monitor buttons in conjunction with the global 'Confidence Monitor' enable switch over on the left of the front panel. Its operation is entirely logical, but the handbook carries all the usual warnings about not using the facility when overdubbing (tracks would be recorded out of sync with each other, of course). Because of the way the confidence monitoring mode works (and the nature of the tape format) when active, track arming is switched in pairs, and so to avoid possible embarrassment, any previously armed tracks are automatically cancelled when Confidence Monitoring is switched on!

Conclusion

The DA98 retains all the positive aspects and flexibility of the DA88, but improves upon them with a more professional user interface and facilities optimised towards post‑production. It is very hard to think of anything that has been left out of the DA98 — it really does appear to be a DTRS machine built to meet the needs of the most demanding professional.