Tonschreiber Ton S.b1 (AEG) 1939

This is the oldest recorder in the Vintage Recorders collection, this recorder stands as a mile stone upon other recorders, these where the machines captured by the British and Americans in the Second World War and thanks to these machines, the development into other machines such as Ampex and EMI began. These machines are very hard to come by, I was fortunate enough to have a friend who had contacts in the sales of military equipment from the first and second world wars, fortunately for me the recorder also came with the reels and a box of spares, it would be very unlikely that I would get another as most of these machines are now on display in museums.

The recorder has the usual basic functions found on any machine, record, playback and rewind, unusual about this machine, the large clock to the left of the tape recorder, this in fact is a tachometer for the capstan as it was hard to keep these machine running at a constant speed hence the fine tuning speed controller. When operating the recorder in play or record, the start-up time was very slow so there is a start button as well as the play function, the start gives the capstan motor an initial boost to get it up to speed, then after a little while the capstan will settle down to the correct running speed. The capstan is driven from two valves, these valves act as the timing frequency to drive the motor, giving a frequency of 20 to 195Hz to the motor, as the valves warm up over time, the speed drifts hence the tachometer to keep an eye on this and make appropriate adjustments if needed.

The recorder has a audio indication tube or valve called the “Glimmtube”, the louder the music, Mores or speech, the more the tube glows but there is no level indication to where the saturation or clipping may take place. This recorder is also thought to be before AC biasing, AEG brought this out in 1941 but it is quite possible that the 1939-1944 models didn’t have this for military use as most of the time the recorders were recording speech or Mores code.

A very unusual feature of the recorder is a rotary head, there is a set of four heads inside the left hand roller directly above the “Tonhöhe” control (Tone), this unusual device was used to change the pitch of the playback but not the speed which the tape moved over the heads, the idea was for translating high speed mores code, you would record the mores at 72cm/sec, then play it back at 36cm/sec, according to the paperwork, the mores signal be no longer be audible at these speeds. By engaging the Tonhöhe control, the heads would spin depending on how fast the operator wanted the effect of passing the heads or scanning the heads over the tape causes the replay frequency to be higher whilst the tape speed can then be reduced.

On the amplifier stage itself, there are two indication meters to measure the emission of the valves, this gives the operator a fast valve tested built into the recorder making fault diagnostics very fast, usually a set of spare valves are kept in the third box for when this fault should occur.
 

Click SSB button to see Spec Sheet Backdrop