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The bulk of early open reel models were transportable recorders, they were sometimes called portable in their day but by the 1960’s 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 60’s except for professional usage where it lived on until about 1980.
Leevers-Rich Synchropulse
Introduced around 1950 by English manufacturer Leevers Rich, the Synchropulse is a transportable open reel audio recorder with film synchronisation capabilities. Originally rented out by its manufacturer but soon thereafter put into serial production it went on to become very popular amongst British film and broadcasting companies and was manufactured with some improvements well into the 1960's. Whilst originally sold as the Synchropulse it was later marketed without the synchronisation capabilities as the Heavy Duty Magnetic Recorder or Series A and formed the basis of other recorders from the company but had by 1960 become seriously outdated and never sold outside of the UK, the last version of the recorder was the Leevers Rich Series E Light although by that time the synchronisation capabilities had become an optional feature.
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.
Specifications:
Weight: 41kg (Transport 24kg - Mixer 17kg)
Tack Configuration, 1/2 Track - 1 Mono Audio & 1 Synch - Later models 1/2 Stereo + Synch pilot track.
Heads: 4 - Erase, Record, Replay & Synch.
Maximum spool size: 7"
Speeds: 38cm..
Leevers-Rich Series E Light
An updated version of the Leevers Rich Synchropulse, the E Light was the last of the 2 box mixer/recorder transportable open reel audio recorder with optional film synchronisation capabilities that the company manufactured. While the unit still had the strobe wheel from the synchropulse it no longer had the tuning fork and 4th head by default but could be ordered as such. Much improved transport taken from the Leevers-Rich Series E with logic control and metered adjustable biasing and audio spec but still looked and sounded dated next to the competition.
Specifications:
Tape Width: 1/4"
Wow & Flutter: 0.1%
Signal to noise ratio: Better than 62dB
Frequency Response: 30Hz to 18kHz.
Tack Configuration, 1,2 or 4 (2 track Stereo being most common)
Motors: 3
Heads: 3 - Erase, Record & Replay (Sync head optional).
Maximum spool size: 11.1/2"
Speeds: 19 & 38cm.
Resources :
Picture and specs..