AEG Tonschreiber B

Description

This landmark recorder comes from the collection of Stuart Blacklock from Vintage Recorders in the UK. It is one of the tape recorders captured by the Allies at the end of WWII and brought back to the USA where magnetic recording technology was almost unheard of. It was machines such as these which were the inspiration for companies like EMI in the UK and Ampex in the USA to begin development of their own recorders.
Tonschreibers (tone-writers) are extremely rare today, most of them are in museums and Stuart was extremely fortunate in obtaining one from someone involved in the sales of military equipment from the first and second world wars.
The Tonschreiber has the usual basic functions found on modern machines. record, playback and rewind, but that is where the similarity ends. The large dial to the right of the tape transport is a capstan tachometer and a fine tuning speed controller. When operating in play or record, the start-up time was extremely slow. A ‘start’ button (in addition to the ‘play’ function) was employed to give the capstan motor an initial ‘kick-start’ to bring it up to speed quickly.

Application : Military

Tracks: full track mono

Speeds: 9cm/s to 120cm/s variable

Number of heads: 8

Head configuration: Erase / Rec / Replay, 4 replay heads in a rotary drum

Motors: 4

Voltage: 110 – 250, I think it will run as low as 50

Frequency responce 50Hz – 8KHz at 72 CM/s ( Higher speeds were worse, 72 was the perfect speed for music, high speeds where used for high speed morse)

Just below the left reel there is a rotating drum which contains 4 heads, below that, an on off rotary switch with speed control.

An operator would record a coded morse message with the machine, then he would use the higher speed settings of the recorder to transmit ( so record at say 72, replay at 120), this meant the frequencies being transmitted were far too fast for anyone to decipher.

A problem arose when the receiver tried to play them back, he would record at 120CM/s then replay at 72CM, problem is that the recording capability at the high end speeds was poor and the reproduction slowed down make it almost inaudible. Introduce the rotating head, you would switch this on and it would in effect resample the tape, the head would be traveling at 120CM/s but the tape at 72CM/s and thought you would then be able to hear the morse again ( not sure if this worked with anything else like speech).