Eight Track Tape Recorder
The Tascam 48 is a high quality eight track recorder which uses the half inch wide tape format and operates at a single tape speed of 15 ips (38cm/s).
Although a three head machine, the record and play heads have identical characteristics, and so the machine would generally be operated in the sync mode where the record head is also used for playback, thus eliminating synchronisation problems. The 48 conforms to the IEC (DIN) standard for record/play equalisation.
Designed with production work in mind, including SMPTE time code facilities (more of this later), the 48 features a heavy duty tape transport system built on a rigid monocoque chassis. It is built to withstand the long hours of continuous use demanded by professional audio or audio-visual production work.
Tape transport is under microprocessor control and incorporates two direct drive reel motors and a single phase-locked loop controlled capstan motor. Unlike the lower priced Tascam 38, the 48 includes additional features such as individual tape/input monitoring switches for each channel and a tape counter calibrated in real time incorporating return-to-zero and search-to-cue facilities.
The varispeed selector provided offers the usual manual speed change of +/- 12 percent but also has an external position which allows the speed of the 48 to be controlled by an incoming pulse train for synchronisation purposes.
Manual and dump editing are easily performed, and a splicing block is mounted on the front panel to aid rapid, accurate editing.
One particularly welcome innovation is the 'spool' mode; when the fast forward or rewind buttons are punched twice, the machine enters the fast spooling mode which facilitates smooth tape winding at a relatively high speed, thus obviating the need to play the tape through at the end of each session in order to prevent uneven tape packing which normally occurs during fast wind.
Operating at the professional +4dBm level, the 48 offers both phono connectors and balanced XLR for input/output connections with a control socket provided for use with a Teac-built dbx tape noise reduction system.
The remote control connector interfaces to the optional RC-71 transport remote control unit and a jack is provided for the connection of a footswitch (RC-30P) for remote punch in/out applications.
The 'D' type Accessory connector carries the necessary inputs and outputs for direct connection to SMPTE time control synchronisers or controllers including capstan motor tach signal, logic, and tally lines. The standard allows plug to plug compatibility with many commercial synchronisers including Audio Kinetics Q-Lock, BTX and ECCO.
SMPTE stands for the Society of Motion Picture and Television Engineers and the current time code, now a universal standard, was defined in 1970. An 80 bit digital code is used to define the exact location on film, video tape, or audio tape and the code carries information relating to hours, minutes, seconds and film frames at either 24fps (frames per second) for film or 30fps for video.
By means of a suitable time code generator, the SMPTE code may be recorded onto one track of each multichannel machine and then subsequently read by a time code controller which will permit two or more machines to run in synchronism by servo control of their tape transport system. Furthermore, this technique enables 'cue points' to be quickly reached on two or more machines and this facility is widely used to 'lock' together two 24 track machines in order to make 46 track recording possible, as well as syncing soundtracks to film or video.
The Accessory socket also provides the SMPTE unit with information relating to transport status, including its direction and speed of travel, and there is an input for a capstan drive reference frequency enabling the record/play speed to be externally varied to maintain synchronisation with other devices.
All the main transport components are mounted on the monocoque chassis and these comprise the capstan and reel motors, the impedance roller, pinch roller, tachometer roller, digital counter and the tape tension arms with their guide rollers.
All aspects of the tape transport are under the control of the 48's microprocessor, tape tension being controlled by a full servo reel system. The capstan motor has a new ceramic end to the motor shaft for better tape speed regulation and the phase-locked loop servo speed control system ensures precise tape speed in the play and record modes.
In common with its budget companion the 38, the Tascam 48 has a row of eight front panel pushbuttons which select 'ready to record' or 'safe' for each channel, whilst a status LED indicates the 'ready' condition. Pressing record and play will then execute recording on any tracks thus pre-selected and silent drop-ins or drop-outs may be implemented by means of these switches whilst the tape transport is in motion. A lever is provided to enable the tape lifters to be dropped during fast wind for cueing purposes but care must be taken not to blow your tweeters when doing this as all the midrange energy is shifted up into the treble region.
Output monitoring is semi-automatic in that the source signal (input) is always fed to the output when a particular track is in the record mode, but a further row of eight pushbutton switches allows channels in the play mode to monitor either source, or the tape signal from the sync head.
These eight source/sync switches also have status LEDs and the facility is useful when performing drop-ins as you can choose whether to listen to the tape up to the point of drop-in, or to your programme input for any channel or combination of channels.
The tape counter is calibrated to register elapsed time in minutes and seconds from the point at which the counter zero is set. If the tape is wound back beyond zero, negative time is registered and the return-to-zero button causes the transport to stop at zero from either direction.
A cue memory is also provided which causes the tape counter position to be memorised when the cue button is pressed. Subsequent pressing of the STC (search-to-cue) button causes the transport to locate and stop at the cue position, a very useful feature for keeping track of strategic points within a piece of music when trying to locate edit or drop-in points.
Unlike the 38 with its 'shuttle search' procedure, the 48 slows down the transport before the zero or cue point is reached, and so there is little or no overshoot, resulting in a faster location time.
Pressing the edit button releases the brakes and applies minimal tension via the real motors so that the reels may be turned manually. Dump edit is implemented by depressing the Edit and Play switches simultaneously and in this mode, the tape is pulled past the heads but not wound onto the take-up reel.
The 48 is not merely a 'souped up' 38 as both the mechanical and electronic design are quite different, although there are some common components including the tape heads.
Apart from the elaborate microprocessor controlled tape transport, the audio chain is also new incorporating low noise circuitry and over 28dB of headroom before clipping occurs.
The reproduction amplifier utilises ultra-low noise FETs in a DC coupled differential amplifier design, reputedly giving improved bandwidth and better transient handling capabilities than more conventional designs. All alignment controls are accessible via the bottom panel and extension cards are provided so that channel boards can be accessed during servicing.
Level monitoring is performed by a row of eight conventional VU meters but each one of these incorporates a peak reading LED to indicate transients that are too short for the meter to follow.
Having been used to the Tascam 38, I found the 48 very easy to get on with and the ergonomic layout is excellent with the possible exception of the return-to-zero and the return-to-cue buttons which are rather small and fiddly for controls that are liable to be in regular use.
The peak reading LEDs are a nice touch but religious adherence to their warnings could cause you to record some sounds at a very low level when your ear would allow you to record them at a higher level. Like any form of metering, they should be used for guidance upon which to base your decisions rather than as a substitute for human judgement, after all your recorded work is ultimately intended for human ears rather than meters so let them be the final arbiter of quality.
The tape path is similar to that on the 38, including the flip-up head shield so tape threading is quick and simple, head cleaning also being easy due to the well thought out head block arrangement which allows full access to all three heads.
The tape transport is fast and quiet in use, the cue memory being particularly useful although the slow approach to the zero or cue point can be frustrating when you are in a hurry. It is, however, faster than the shuttle procedure employed by the 38 and the transport is generally quite gentle towards the recording tape so it's a minor point that one could easily live with.
In all the other respects, the machine works so well that it is soon taken for granted and even without additional noise reduction, the signal-to-noise ratio is a very acceptable 69dB NAB (A weighted) providing that the input levels are kept as high as are reasonably possible.
I can't comment on the ease of setting up and aligning the machine as I had no cause to adjust anything (and no calibration tape was available), but there is no problem in gaining access to the relevant electrical and mechanical adjustment points.
The Tascam 48 is a simple to use machine with truly professional facilities which falls directly between the 38 and 58 models in terms of price.
With the exception of the minor niggles concerning the small autosearch buttons, the 48 is so easy to operate as to be almost user transparent, the comprehensive manual supplied with the machine giving a lot of valuable background information as well as specific instruction and technical details.
The construction of the machine inspires confidence with regard to its reliability but it will be interesting at some future date, to hear from someone who has had one in constant use so that we can see how our impressions compare with real life.
If you make your living from eight track recording, the 48 probably presents the best blend of economy and professional features available and in this respect, it offers good value for money. Many of these machines will undoubtedly find their way into audio-visual production suites where the SMPTE compatibility will be exploited to the full.
On the other hand, if you run a small studio that works long hours for little reward, this machine will probably stay up and running for extended periods without much in the way of major maintenance.
The Tascam 48 retails at £3060 inc. VAT.
Further details from UK distributors Harman UK Ltd., (Contact Details).
Review by Paul White
Previous article in this issue:
Next article in this issue: