The Nagra T-Audio Tape Recorder

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This is the mighty Nagra T-Audio, a most complex and interesting tape machine which
was quite unlike any other audio recorder. This exotic and very costly device was
introduced by Kudelski in about 1976. It is of modular form and uses a tape transport
based on (and looking very similar to) the Nagra Ti instrumentation recorder. It was also
the only 'full-sized' audio tape tape machine that Nagra /Kudelski produced, and was an
ideal studio counterpart to their famous portable audio recorders.

The machine above was made in 1990 and has the later '2nd version' control panel but not
the optional meter bridge. It is shown in shuttle mode, with the tape stopped and the
travelling pinch roller carriage partly retracted away from the heads.

The Nagra T-Audio was available in a number of options, but was also supplied in two
basic transport versions of tape transport:

Type NTA.2S - 2.75mm track 'Stereo'

Type NTA.2B - 2.00mm track 'Broadcast'

The Stereo stereo version came with a full track erase head and was intended as a straight
forward high quality audio mastering machine, whilst the Broadcast version was actually a
two track 'multitrack' recorder (in that the two channels were individually switchable
between record and play back).

Both base machines would then have various options added. These included a clever
manual editing mode (with automatic placing of tape over the built-in scissors at the press
of a button), headphone and internal loudspeaker monitoring, very comprehensive time
code and 'Pilot' facilities, and an add-on meter bridge of varying configurations.

The Nagra T-Audio was magnificently engineered and certainly much too expensive for
basic commercial recording studio use. This was the territory of the Studer the Ampex and
the Otari, the big Nagra on the other hand was a film and video post production tool. The
basic Nagra T-Audio 'mainframe' was well over £10,000, but when loaded with various
time code, pilot and serial control options (at some £5,000+ extra), it became successful
in the comparatively wealthy video post-production environment as what was known as a
'lay back' machine. (Another 15k recorder would be hardly noticed at a time when

broadcast video recorders were well over double this sort of figure.)

The Nagra T is the only analog audio tape recorder I know that can 'jog and shuttle' tape
just like the big editing video tape machines can; it does have a beautifully weighted and
smooth jog/shuttle wheel after all. (Actually, connected to a linear video editing controller
it behaves just like a video recorder - but without the video, You can even feed station
'black and burst' syncs to the machine to keep it in perfect lock. It can also just sit on an
'RS-422 bus between the edit controller and the video recorder and copy all the
commands. The edit controller will not even be aware of its presence'...)

At a maximum velocity of 10 meters per second it also has the fastest wind speed that I
have seen on any tape machine. And it was probably the most sophisticated and complex
two channel (analog) audio tape recorder ever made. Not only is it fabulously well
engineered and assembled, it is also very gentle with the tape and has the most remarkable
speed stability and wow and flutter performance. Perhaps there were other worthy
alternatives to this Swiss machine (the Ampex ATR100 is something of an audio legend),
but put them all in the same room and there is just no contest in wow factor. One might
also ponder that some specially modified versions of the Nagra T transport are still used
for the very serious business of replaying 'black box' voice recordings from crashed
aircraft.

(Click on the image above for further pictures and comments.)

SPECIFICATIONS (from the Nagra T-Audio instruction manual):

Tape counter accuracy 0.1%

Tape speeds:

(Most machine came fitted and EQ'd for 2 speeds, but the transport may be internally
switched for playback of 4 speeds.)

3 3/4 ips

7 1/2 ips

15 ips

30 ips

Speed accuracy>0.07%

Wow and flutter30 ips better than 0.025%

15 ipsbetter than 0.032%

7.5 ipsbetter than 0.04%

3.75 ipsbetter than 0.05%

Frequency response30 ips50 Hz to 20 kHz +- 2 dB

(Record + replay)15 ips30 Hz to 20 kHz +- 1.5 dB

7.5 ips30 Hz to 15 kHz +- 2 dB

3.75 ips30 Hz to 8 kHz +- 1.5 dB

Signal to noise ratio (TACAL-s) ASA RMS A weighted

(CCIR - Agfa PEM-468)

30 ips73 dB(810 nWb/m and 2.5% 3rd harmonic distortion)

15 ips71 dB(810 nWb/m and 2.5% 3rd harmonic distortion)

7.5 ips65 dB(640 nWb/m and 2% 3rd harmonic distortion)

Record + replay distortion at a nominal 510 nWb/m - OVU

15 ips1.5%

7.5 ips1%