An attractive price and ease of operation make Tascam's ATS500 ideal for semi-pro musicians with an eye on the field of audio-for-video. Dave Lockwood checks it out.

Tascam's ATS500 is a transport synchroniser, offering not only audio-to-audio synchronisation, but also allowing sync-to-video using just a domestic (ie. VHS) video recorder. With semi-pro equipment being used ever more in the audio-for-picture field, this is a timely product indeed.

The ATS unit has been stripped down to the essentials for synchronised operation, and therefore has no transport or record controls of its own — the combined system is driven from the master transport, and machines must be dropped in and out with their own controls. More than one slave machine can be used however, by cascading further ATS units.

The system normally interfaces via RS232C serial connections (9.6kHz baud rate), such as Tascam's Accessory 2 socket on many of their current recorders, but transports with a parallel interface can still be used, with the addition of Tascam's IF500 serial/parallel convertor unit. A code generator is incorporated, both reading and writing all varieties of SMPTE/EBU, free-running or locked to an external reference.

SIMPLE OPERATION

The 1U, half-rack chassis has a 2-line green LCD screen for displaying timecode values and system prompts; operators used to more prominent timecode displays may find this a little on the small side, but in typical usage, it proved an acceptable compromise. An external 12V DC PSU is used, but a front-panel power switch is still included. The comparatively small number of switches which control the system are all grouped to the right of the front panel, with Lock and Code indicators to the left. Sync Lock is lit when the master and slave timecode values are within +/-3 sub-frames (100ths of a frame). The final approach to lock-up, over a four frame window, is displayed via 'arrow' indicators, on either side of the Lock lamp.

The familiar menu system is used to access all functions, making the system particularly simple to operate, without undue recourse to the manual — if you can operate MIDI gear, you will certainly be able to drive an ATS500. Briefly, the Group key is used to cycle round the primary functions; Timecode, Offset, Generator, and System. The Menu key then accesses the sub-functions, allowing values to be changed via the data Inc/Dec keys. With the Shift key held, these act as cursor keys, for moving around the screen.

CONNECTION

Phono connectors (the standard audio connector for -10dBV systems) are used for timecode and video sync signals, with 15-pin D-subs used for the serial ports. Timecode Out is provided for striping, and a Thru output is also included, echoing the signal at the Master Timecode In socket. Timecode connections are completed by the Slave Timecode In socket. When a video transport is used as the master, Video In accepts the video sync signal, echoed to Video Thru. A 4-way DIP switch is used to set up the video interface for either professional or consumer video formats, and also offers independent earth-lifts for master and slave connections.

OPERATION

Before synchronised operation can commence, a simple set-up routine must be run to allow the ATS to 'learn' the characteristics of the connected transports. A successful set-up will terminate with a Master End, Slave End display, and you can then use the Chase key to initiate lock-up. There are three basic sync modes; Chase and Lock; Phase Lock; and a combined Chase and Phase mode. Chase is the normal mode of sync operation, matching master and slave timecode position frame-for-frame (unless there is an Offset entered). Phase Lock ignores the 'time-of-day' element of the code, effectively just clocking the slave with either the frame edge of a video signal, or timecode sync words. Chase-Phase can be used to deal with discontinuous code — so long as there is enough code to achieve initial lock-up in Chase mode, Phase Lock will then maintain sync.

The time taken to achieve lock-up is of course determined primarily by the performance of the transports in use; using two MSR24s, with their matched handling characteristics, proved to be particularly satisfactory, therefore. Sync to video, in a code-only-master configuration, was naturally a much less efficient operation, but the requirements and expectations are obviously different to those of a dual multitrack set-up.

Apart from speed of lock-up, a synchroniser's performance must be judged by its ability to achieve lock accuracy without generating wow or flutter through speed fluctuation. It must be responsive enough to make the necessary adjustments to maintain accurate tracking of the master, and yet sufficiently 'damped' to avoid generating any audible anomalies. The ATS500 proved itself to be most reliable during an extended test period — with the one curious, but extensive, lock-accuracy failure ultimately traceable to a total system fault, rather than an ATS problem.

Short-term code interrupt, such as might be generated by a tape drop-out, causes no difficulty; the system merely free-wheels across it. The rather more drastic removal of the code connection altogether, for either master or slave, obviously loses sync, but nothing untoward happens — there is no uncontrolled fast-winding in search of a non-existent timecode value.

OFFSETS

Entering offsets, to lock the master and slave at different timecode values, is a simple procedure. Offset is accessed via the Group key, with the offset value (ie. the required difference between the master and slave times) entered via the data Inc/Dec keys. Shifted Inc/Dec is used to move between columns. An offset value may also be picked up on-the-fly in Offset programming mode, simply by pressing Enter whilst reading code from both transports. The difference in tape positions is then automatically registered as an offset.

The offset value may be selected as the timecode display mode, instead of the normal master or slave value. Relative or Absolute may be selected, with Relative merely showing the distance from lock-up (ie. zero when locked, irrespective of the programmed offset distance).

CONCLUSION

The ATS500 makes transport synchronisation more accessible than ever before, not just through economical pricing, but through its simplicity of operation, demystifying one of the areas still seen primarily as the province of the pro operator.

Products like this, combined with the ever-greater sophistication and quality of semi-pro recording equipment, are opening up the lucrative audio-for-video market to practically anyone with a desire to work in that field. This unit is perfectly specified, offering just the essential features for this type of work, at a price that is sure to attract many users who have previously been wary of venturing into transport sync.

Further information

Tascam ATS500 Synchroniser £527.58 inc VAT.

TEAC UK, (Contact Details).