The bulk of early open reel models were transportable recorders, they were sometimes called portable in their day but by the 1960ís truly portable recorders had arrived in the mass market and the term transportable had taken over. The bulk of the transportable models do not have any capability to be run from batteries but rather are intended to be connected to the mains although there are exception to this and most of the also need at the least 2 people to carry around, it is no uncommon for them to be 40 kilograms although most of them are 20 to 30 kg. The transportable was in other words a transportable replacement for a studio or home console recording unit rather than a truly mobile alternative one like we see with the Vintage portable R2R's. This format more or less disappeared in the late 60ís except for professional usage where it lived on until about 1980.
The speed control and synchronisation mechanism of the Synchropulse was rather novel. Since the unit had a DC motor you had to manually adjust the speed when running on mains power, the Synchropulse has a strobe wheel similar to what you would find on a turntable and at the beginning of each session had to align the speed by hand and monitor it during recording and playback. When running on batteries you had to strike a 50Hz tuning fork that had shutters in it and align the speed by looking at the strobe wheel through the shutters until the 2 matched.
Synchronisation was performed by fitting make or break contact into a film camera so that you would get 1 make per frame, that switch controlled a 1kHz oscillator built into the tape recorder so each frame was represented on tape as a burst of a carrier modulated 1kHz signal, although in the fifties this was changed to a 400Hz, in both cases recorded at 12dB below level. The resynchronisation while transferring to sound-film was done manually, the Synchropulse controlled both the speed of the camera and the tape, the output of the synch head was placed into an oscilloscope and alongside a camera synch reference and you interactively aligned the tape recorder speed until they matched on the scope. An automatic synchronisation system was developed for the Synchropulse in the 1960's but Leevers-Rich had lost the market to the Swiss based competition by then.
Note that the recorder uses a unique track arrangement that is not fully compatible with anything else on the market although in most cases it is close enough to other 2 track machines, with a 2mm tack on each end an a 1mm space in between, so transferring material recorded with those needs to be done with care. In the 1950's a stereo version of the Synchropulse was developed that copied the Telefunken System? by using a 0.6 mm pilot? track to record the pulses on this allowed for stereo recording while still maintaining compatibility with older recordings.
Leevers-Rich Series E Light