Nagra T-Audio
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.
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
Nagra SN
More like an exercise in watchmaking than an audio recorder, the increasingly collectable Nagra SN is yet another delightfully tactile object from this famous Swiss company.
Mr Tim Blackham's very early and un-legeneded example is shown above on the Left, and my own later full track mono* version is shown lower Right. These truly pocket sized and light weight reel-to-reel tape recorders were in actual fact true professional sound recorders in every respect, and were a very far
cry from almost every other similar sized tape recorder. While various 'toy' miniature tape recorders of the 'Misson Impossible type' produced results varying from excruciating to just plain bad, this little Nagra gave real Hi-Fi quality. Actually I sometimes use mine into an HH AM8/12 amplifier and a Tannoy Monitor Gold in a Lancaster cabinet with pretty impressive results!
With built-in 50 Volt capacitor microphone powering and a proper capstan servo system, the Nagra SNN was quite capable of making studio broadcast quality recordings at the relatively low speed of 3 3/4 inches per second on 1/8 inch wide tape. (Which was actually re-reeled Compact Cassette tape - see below.)
Perhaps more famous for its 'security applications', this 'spy Nagra' was often used as a concealed film location recorder before the arrival of reliable radio microphones. Simple in use; you just plugged the microphone or line input lead into the machine to put it into record mode. It didn't have fast forward, and rewind was done by hand by turning a miniature fold out 'starting handle'. But this rather quaint feature was perfectly usable and saved the batteries.
Nagra SNN
Above is another view of Mr Blackham's unusual Nagra SNN. As far as I can see, apart from not having the various anodised legends on the deck plate, also absent are the adjustable AGC threshold knob and the transport lock-out 'switch' next to the meter. The cover 'hinge' arrangement differs slightly from later
machines, as does the 'patina' of the anodised finish. A most interesting version, has anyone got another? (Apparently yes, I have recently been advised.)
* For those who are looking at the stereo versions of this recorder often to be found on 'Eday', do beware, as It is unlikely that these will be the recent versions designed to record high quality music.
There are now apparently four versions of the Nagra 'SN':
Nagra SNN - full track recording at 3 3/4 and 1 7/8 i.p.s. - high quality recording in Mono
Nagra SNS - half track recording at 1 7/8 and 15/16 i.p.s. - surveillance quality recording in Mono
Nagra SNST - Stereo recording at 1 7/8 and 15/16 i.p.s. - surveillance quality recording in Stereo
Nagra SNSTR (recent) - Stereo recording at 3 3/4 and 1 7/8 i.p.s. - high quality recording in Stereo
Apparently for covert surveillance use it was preferable to have two separate recording channels to have some chance of capturing a muffled or distant conversations. So these older stereo machines will therefore be optimized for speech recording only, and will also run at low speed for maximum recording time and not fidelity. Actually Nagra made a special playback loudspeaker system (25100 DSP) with built in equalization to compensate for the quite limited frequency response of these
recorders. A standard mono Nagra SNN running at 3 and 3/4, like the ones on this page are capable of truly Hi-Fi recording, but the slow speed SNS and the SNST stereo versions are not. Perhaps it might be possible to convert these machines for Hi-Fi use, but this would involve replacing most of the electronics and be very expensive.
Cheaper to buy a rather better stereo IV-S in the first place!
Tape for the Nagra SN
I have been amazed at the prices some people have been willing to pay on that wild west auction site for the little reels of tape for this machine. When I first acquired my example from the BBC naturally I wanted to play with it and make some recordings. I knew that the tape was basically re-reeled cassette tape so I approached a tape duplication house in the UK and quite easily obtained a few part used 'pancakes'. These are the un-flanged bulk reels of tape (about 10" dia) that are automatically wound into the cassette shells. I then contacted Nagra UK (always helpful) and obtained for around £15 each several pairs of empty plastic reels. It then was quite a simple matter to wind tape off the pancake and onto the Nagra plastic reel (by using the hand crank on the machine). I did this a few years ago and things may be slightly different these days, but perhaps worth investigating rather than spending some VERY silly money.