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Hands On: Casio DA7 DAT Recorder

Article from Sound On Sound, August 1992

Casio's DA7 is one of the cheapest DAT recorders on the market, yet it is still a suitable machine for mastering. David Mellor reveals its better features and finds ways round a couple of problems.

Casio's DA7 is one of the cheapest DAT recorders on the market, yet it is still suitable for mastering. David Mellor explores Casio's mighty midget.

If you have a nose for a bargain, you've probably bought yourself a Casio DA7 already. It has plummeted in price since its launch and you can find one, if you shop carefully, for not much over £300. Is this low price an indication that the unit is no good and that potential purchasers are snubbing it in favour of more highly specified machines, or ones with better sound quality? If you buy one now will you live to regret it? I used to have doubts about low-cost DAT recorders — the technology is complex, the scale of the recording process itself is microscopic, and if the end result is a less than perfect master tape, surely low-cost DAT must be a false economy. It wasn't until I saw a Casio DA7 in regular use, receiving its fair share of abuse as well, that I realised that I wouldn't have to pay over £1,000 for my second DAT machine; I could buy a DA7 for £350 (its price a few months ago) and leave the rest in the bank to gather interest.

Despite its better qualities, the Casio DA7 does have a few failings, and if you are a professional sound engineer then you are more likely to prefer a proper professional model, but I and many others are prepared to work around certain deficiencies as long as the end product isn't compromised. As you doubtless know, there are other low-cost DAT machines available, such as the Aiwa HD-S1, the Sony TCD D3, and the Casio DAR100. For me, however, these are ruled out completely by their connectors. Phono connectors are small, fiddly, and potentially unreliable if you don't inspect them regularly, but if you treat them with a bit of respect they will do the job. Mini-jacks, on the other hand, are out of the question for my purposes because I need to know, when I am recording a live concert, that there is absolutely no possibility of coming back with a tape that is anything less than complete and perfect.

One problem with the DA7 is that it is very difficult to figure out how to operate its finer functions without recourse to the manual. Obviously front panel space is limited, and I have to say that I very much prefer to have the basic transport controls presented on large, well-spaced buttons. The last thing you need when your client is asking to hear a particular section of a recording is to have to fiddle about with miniature buttons, as found on the smaller recorders. And while I am on the subject of problems, let me point out that there is a bug in the DA7's programming. You may find yourself at any time and for no apparent reason unable to control the machine. Is this a cue for panic? No — just follow the simple procedure that I will outline shortly.


The DA7 can be operated from an external mains power supply or from its internal rechargeable battery. If you are using the mains supply, be absolutely sure that you connect it the correct way round — it is possible to force the connector in the other way round and if you do this the machine will emit a small puff of smoke and cease to function. Another important point is that if you are using the mains supply then you must set the switch on the rear panel to 'AC/charge'. If you don't, you will be running from the battery, which might run down when you least expect it. In the studio, this is an inconvenience and an embarrassment; in a live recording situation it's a disaster.

Whether running on battery or mains power, switching on the DA7 is a simple matter of flicking the power switch to the right. If you do only this, then the machine will switch itself off again after six minutes to save power — a potential irritation to serious users. Fortunately, there is a way round it: hold the Stop button down as you switch on, and things will be as they should.

At this stage, you really need to know something about how the DAT system works. Your newly unwrapped tape will be completely blank, with the magnetic fields of its metal particles randomly orientated. When you record onto the tape, the record head lays down a pattern of tracks which contain the digital audio data. If you subsequently erase this recording by recording over it with the input level set to zero, then the pattern of tracks will still remain. Thus there is a difference between an unrecorded section of tape and an erased section — the latter has a pattern of tracks recorded on it. The DA7, like other DAT recorders, can tell the difference between the two.

Let's assume that you are using a new DAT tape for your recording. Press the eject button and load the cassette. If you are recording from the line inputs then make sure that the Input switch, on the top of the machine, is set to Line. On many machines, recording is initiated by pressing the record and play buttons simultaneously. On the DA7, you can do it like this instead:

Press the Rec/Mute button. The red LED will flash to indicate that the machine is recording a five-second blank space at the start of the tape. (It is recommended practice to have at least 30 seconds of recorded blank at the start, but I can understand Casio thinking that most users won't be prepared to wait.) During this period there will be no level indication on the meters nor monitor signal from the output.

After a short time, the Pause symbol will appear in the LCD display and the LED will continue to flash. You will now be able to set the recording level, and if you are monitoring the signal from the outputs you will now be able to hear something. The recorder is now ready.

Press Play or Pause to start recording.

That was the full length version. Once you have set your levels, it is easier to initiate recording by pressing Record, then Play immediately after. As with all DAT recorders you are advised to allow the tape to roll for at least 15 seconds (some would say 30) before you start your source material. This is so that when you are copying digitally the destination machine has time to lock up to the sampling rate of the source. If you don't leave this gap, you may be forced to copy via the analogue outputs, which is obviously less than ideal.

The meter on the DA7 reads from -50dB to 'Over', which you might be inclined to take at face value. However, 'Over' really means 'not quite over yet', so your recordings will end up being a little lower in level than you might expect if you always play safe. I don't get too excited if the Over segment lights up occasionally. I always monitor the output anyway, and if it sounds OK to me, it is OK.


ID codes on DAT are a great invention. The Casio DA7 can implement Start and End IDs, but not Skip, which is a bit of a pity — I use them all the time on my Sony DTC1000ES. In normal operation the DA7 records Start IDs automatically, which can be a problem since your tape will end up peppered with IDs in all the wrong places. I doubt if you will be able to figure out, just by looking at the machine, how to switch off the automatic Start ID insertion, but it is possible. While the machine is in Record Pause mode, press the Mode button. This will switch the 'Auto ID' flag in the display off. What's more, you can still add IDs manually as you record, by pressing the Play button each time you want one. It's a bit disconcerting to press the Play button while you are in the middle of an important recording, but it inserts Start IDs, just like the manual says.

During the recording session, it's likely that you will want to wind back and listen to certain takes. Usually, you then have to be very careful to go back exactly to the end of the last thing you recorded, otherwise you might erase something valuable. But if you started off with a new, unrecorded tape, the DA7 will handle this for you. If you stop playback anywhere in the recorded section of the tape and press the Fast Forward button, the machine will stop automatically at the beginning of the unrecorded part of the tape. This is particularly convenient, but unfortunately it can only work with new tape. If you are re-using an old DAT cassette which was formerly recorded right to the end then there will be no unrecorded sections on the tape, therefore the DA7 will just wind straight to the end. If you are thinking that it would be a good idea to bulk erase the tape before use, well, you're right; but bulk erasers that are powerful enough to erase high coercivity DAT tapes are extremely expensive.


Once you have successfully captured your material you may wish to edit the Start IDs and possibly add an End ID. If you want to add a Start ID, press the Mode switch once while the machine is stopped or playing. Play up to the point where you want the ID inserted and press Play while the tape is running. It's usually best to make a note of the timer reading so that you get it in the right place, just before the start of the programme item. Start IDs are recorded for 12 seconds, so be ready for a short wait.

It's more than likely that you will have some Start IDs in the wrong place, so you need to know how to erase them too. Stop the tape in the middle of the ID you want to ditch, and press the Mode button twice. Now press Play and the machine will set about erasing it.

While you have been doing this you will undoubtedly have discovered the operation of the forward and reverse Skip buttons. These allow you to skip forwards or backwards from ID to ID. Unfortunately there is no way of programming the machine to go directly to, say, ID 45 — you have to press the skip button 45 times. You'll get used to it.

Although most DAT machines will automatically number Start IDs consecutively as they are entered, I find that tapes inevitably end up with unnumbered IDs (which happens when you manually enter them out of sequence) or that you can end up with more than one ID with the same number. To deal with this I always renumber the IDs, using the function of that name. On the DA7 it's a simple matter of pressing the Mode button three times and then pressing Play. The machine will wind back to the beginning and make sure that all the Start IDs on the tape have consecutive numbers.

The End ID is also worth a mention. This is used to indicate the end of the programme, whether or not there is recorded material further upstream on the tape. To enter an End code, locate the point where you want the end to be and enter Record Pause mode. Press and hold the Mode button for two seconds and you will see 'EE End' in the display. Now press Play and the code will be inserted. If you ever come to re-record the tape this code will be ignored and erased.


One valuable feature that the DA7 has that is absent on my otherwise much-loved Sony DTC1000ES is Absolute Time (or A-Time). This is yet another DAT subcode which registers the time since the beginning of the tape. This is not like a conventional tape timer or counter that you can reset at any point — it is always the time from the beginning of the tape — and it has the great advantage that it is always accurate, with no problems due to counter slippage. On the DA7 you have to make sure that you start the tape from the beginning to record Absolute Time — a reasonable request, I think. To display Absolute Time during recording or playback, press the Time button until you see 'ABS' in the display.

Two other useful time displays are Program Time, which tells you the time that has elapsed since the last Start ID, and Remaining Time, which tells you how much tape you have in hand. There is also a simple counter mode, which you would presumably only use if you were playing back a tape without Absolute Time recorded on it.


The worst problem with the DA7, which I have seen on the two examples of the unit I have handled, and therefore presume it to be a software bug, is that it seems prone to the occasional brainstorm. This may manifest itself as an inability to respond to any controls, or you may think the machine is recording when in fact it is just turning the tape. This last one is the real problem, but you can spot it by the fact that there is no Absolute Time indication during recording (there normally would be one). The simple answer in both cases is to eject the cassette and load it again. Simply switching the power off and back on doesn't cure the fault, even though it's the standard solution to many of the recording world's ills.

Another problem which could catch you out is that every time you stop the DA7 after recording, it winds back a couple of seconds. I'm sure it does this for a good reason, albeit one of which I am unaware. The potential result is that you could clip the end of the last thing you recorded. I have done it myself and I have seen others do it. The answer is simple, however: just record for an extra couple of seconds at the end of the take, or five seconds to be on the safe side.


I make a distinction between problems and drawbacks, and I wouldn't expect absolutely everything to be perfect on a machine at this price. I would, however, have really loved a backlit display. This one really is very dim and difficult to see. Another drawback, which other affordable machines suffer, is that it will only record from the analogue inputs at a sampling rate of 48kHz. Unfortunately 44.1 kHz is the standard for CD mastering, so your master tapes will have to be copied via the analogue outputs or digitally converted. Also, the DA7 uses pre-emphasis, a technique which involves boosting high frequencies during recording and cutting them back on replay, which increases the signal-to-noise ratio. Since most machines will have provision for de-emphasis, and do it automatically, you won't have any problem playing back your tapes, but this technique inevitably reduces high frequency headroom. Compact Disc also has a provision for pre and deemphasis but it's a rare CD these days that uses it. If you are using a DA7 to collect sample material, then you need to be aware that if you transfer digitally into an S1000 via the IB-104 interface, the pre-emphasis will not be corrected and the sound will be excessively toppy.

The final drawback is, of course, SCMS, which is, as ever, an unwarranted intrusion into the lawful activities of home and professional recordists. Fortunately for me, I have my pre-SCMS Sony and I can make as many generations of copies as I like as long as I always copy Sony-originated recordings from the Casio to the Sony, and Casio-originated recordings from the Sony to the Casio. And despite having this unlimited copying facility I still don't, after four years of DAT ownership, have any illegitimate copyright-busting copies on my DAT shelf! If I didn't have the Sony, then I would undoubtedly invest in one of the SCMS strippers which have recently appeared on the market. It's just a shame that such devices are necessary.


Since this is an article in the Hands On series, I think my recommendation ought to be to get your hands on a DA7 quick before Casio realise that they have an underpriced product on the market. How DAT prices will go in the future I can't tell, as DCC and MiniDisc loom on the horizon for hi-fi enthusiasts, but here is a machine which, with some limitations, is suitable for professional use and an absolute steal at its current price.


SCMS (Serial Copy Management System) identifies any DAT cassette as belonging to one of these three categories:

1. Digital copying prohibited
2. One generation of digital copying permitted
3. Digital copying permitted.

If the DA7 is used to make a recording from its analogue inputs then the result will be a tape of the second variety. If this tape is digitally copied then the result will be a tape which is of the first type, and therefore no further generations of digital copies may be made. Of course, you can make as many generations of analogue copies as you like, but you will lose a little quality each time.

The idea of SCMS was to defeat large scale piracy, but the large scale market for pre-recorded DAT tapes never developed, and therefore there is no piracy to defeat — and did anyone seriously think that pirates would worry about copying via the analogue outputs? So what is left is just a gross inconvenience for home and professional recordists. Fortunately, however, there are at least two sources of little black boxes to defeat SCMS.

The first such device to appear in these pages was the Thatched Cottage Digital Stripper (£175), with which you can copy otherwise digitally uncopyable tapes. The only slight drawback is that you have to use it each time you make a copy; you can't make a Copying Permitted tape with it, which I suppose must be a sop to the people who imposed this system on us in the first place — the record companies. Audio & Design's Copy-Rite (£151.58) will make Copying Permitted tapes at 48kHz, but you still have to use it each time you copy if you originally recorded at the 44.1kHz sampling rate. For complete satisfaction and SCMS freedom you will need Audio & Design's SmartBox, which will completely zap SCMS and also allow you to copy from a domestic machine with SPDIF connections to a professional machine with the AES/EBU interface, or vice versa. This will cost you around £500 — a little out of proportion with the cost of a DA7, but I don't think it's really aimed at the home recordist.

Thatched Cottage Audio (Contact Details).
Audio & Design (Contact Details).

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Publisher: Sound On Sound - SOS Publications Ltd.
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Sound On Sound - Aug 1992

Feature by David Mellor

Previous article in this issue:

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