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-legended 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 'Mission 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.
The Nagra SN
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.)
Click on either of the above images for more information.
* For those who are looking at the stereo versions of this recorder often to be found on 'eBay', 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 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 on to 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.
To change the batteries of the Nagra SN series (the machine uses 2 AA cells, which will run the machine for several hours), the bottom cover is easily removed by undoing 3 captive screws.
SN electronics are a mixture of once conventional miniature components and newer surface-mount leadless items. There are 7 plug-in modules in this machine that mate to 3 smaller 'mother' boards fixed to the milled-from-the-solid alloy chassis.
To prevent interference with the play back head, the direct-drive servo-motor (larger flat grey cylinder in the above image) uses capacitive speed sensing, and has a mixture of oilite and Jewelled bearings. It is worth knowing that the end cap jewel of the capstan can be broken if the machine
suffers a severe knock.