Sony DTC-A6

Sony quietly dropped its Digital Audio Tape format in 2005, but it had long since been on the critical list. Indeed, the launch of the DTC-A6 in October 1996 saw the last important high end consumer DAT machine to come from the Japanese electronics giant. Although DAT didn’t spool its last reel until nine or so years later, Sony effectively ended development of its machines with this. Everything that followed was the same supper, reheated and served on a different dish less tastily. From this moment in the mid-nineties, each new range of Sony DAT decks that followed was ever more cheaply built and stripped of ever more facilities.

Think of the DTC-A6 as being the last of the summer wine from the golden age of DAT – because it was young enough to have plenty of refinements that the older models lacked, and old enough not to have been cost-cut into oblivion, like the models that followed. Indeed it sports a refined version of the company’s three-motor transport and the (annoyingly titled) Anti-Resonant Midship Drive. Earlier DAT machines had a more complex and more bug-prone transport, and these were mounted to the left of the fascia. This mech allows a fifty second rewind time, and reliable 200 or 400 times high speed search. The deck also has Sony’s ‘Pulse’ D/A converter; this is a good Bitstream device that’s smooth and clean sounding, although wins no prizes by modern standards. There’s are about coaxial and optical digital outputs of course, so it can be hooked up to a snazzy modern DAC, whereupon it sounds very good indeed.

The recording side is interesting, because – unlike early DAT machines such as 1987’s Sony DTC-1000ES – it has a choice of recording at CD quality 16/44 or DAT’s best 16/48 resolution (and the latter sounds surprisingly better); feed it a CD and it will automatically choose 16/44. It also has the aforementioned 12/32 Long Play mode. The real gem is Super Bit Mapping; it may have long since been forgotten about, but this was Sony’s magic digital signal processing system which intelligently noise-shaped the digital input stream. Despite being a 16-bit format, the DTC-A6 has 24-bit analogue-to-digital converters, and Sony’s SBM system optimises how this extra audio data is discarded to make the remaining 16-bits sound as good as possible. It weaves out the least significant 8-bit information into the 16-bit filtered data. The company claimed that by reorienting quantisation noise to above 15kHz, Super Bit Mapping gives a sound that’s almost comparable to 20-bit quality – yet it’s still accessible via any SBM-encoded DAT via any player. Only later Sony machines have this, and it’s a very valuable feature to have if you do a lot of recording from analogue sources.

Ergonomically, the Sony is no masterpiece. The company was fond of festooning its products with buttons in a rather matter-of-fact way, and it’s no different with the DTC-A6. Still, all is pretty self explanatory and the deck does have a fine quality fluorescent display which is highly informative. This is to the left of the fascia, alongside the track start ID controls; to the right of the central tape drive are the transport buttons and recording mode selection, alongside the rotary input level control. Unlike Sony’s earlier DAT decks, this is largely duplicated on the supplied remote control. This doesn’t have the really solid build of early DAT machines, and feels a little insubstantial. However, in general operation its far less clunky than the earlier, late eighties machines.

Sonically too, the DTC-A6 is better than earlier DAT machines. The later DAC and digital filter help here, with a smooth sound that’s peppered with detail and incision. By today’s standards it’s a little genteel perhaps, lacking real dynamic punch – but pipe the digital audio stream out to a modern DAC and you’ll be very surprised. Better still, make an analogue-sourced recording with SBM switched in, at 48kHz, and you may be amazed how good it can sound; it’s in the realm of hi-res audio and a good bit better than standard CD. DAT might be old and decrepit, but can still make fine recordings if properly set up. The standard quoted frequency response is 2-22,000Hz (±0.5 dB), or 2-14,500Hz (±0.5 dB) in Long Play mode. It also has a better than 90dB dynamic range and less than 0.005% total harmonic distortion and effectively zero wow and flutter. Warp back to 1987, and that sort of specification from a tape format really did astound people. 

In December 2005, Sony ended DAT machine production, after around 660,000 decks of various descriptions had been sold since its launch. Although it failed as a replacement for Compact Cassette, it did however gain a second wind in small professional recording studios – and countless early nineties dance records were mastered on DAT. Sony also refocused it as a computer storage medium, which became the Digital Data Storage format. It still pops up in some film and TV recording, too.

That’s why it’s still possible to pick up machines such as this, if you look around. Many were hammered by small studios and home recordists, so the physical condition of the unit is vital indicator. As ever with any old hi-fi piece – and especially a tape-based one – buyer beware! Prices vary from around £50 to £300; as ever check the condition carefully and try before you buy. Most DAT machines are only one step away from the dump, and the people that are willing to service them are now few and far between. Yet still mint, privately owned, low mileage examples do pop up now and again, and these are the ones to have.

So farewell then, Digital Audio Tape. It is pretty much consigned to the great hi-fi graveyard in the sky, where it can rest quietly with Sony’s other glorious failures; Elcaset and MiniDisc. DAT machines are still worth having if you do home recording – especially vinyl archiving – for this job get one of Sony’s later SBM-equipped decks like the DTC-A6. In truth though, it’s an idea whose time has long since passed – and another glorious failure from the once brave and innovating Sony Corporation.