The Sony PCM-3348 became the go-to choice for recording studios, broadcast stations, and postproduction houses around the world. It holds the distinction of being the first digital 48-track audio recorder. This achievement highlighted Sony’s innovative technology and creative design, building on the success of the earlier Sony PCM-3324, a 24-channel DASH format recorder.
After an extensive international survey of customer feedback, many new features were added to the Sony PCM-3348. With its outstanding digital multi-track performance and robust operational features, the Sony PCM-3348 is poised to meet the evolving needs of the professional audio industry.
The Sony PCM-3348 is based on the DASH-F (Digital Audio Stationary Head — Fast speed) format. It records/reproduces tracks 25 to 48 in the spaces between tracks 1 to 24, resulting in 48 channels of digital audio recording/ reproduction on a half-inch tape. The DASH format features an additional four auxiliary tracks: CTL signal, time code and two cue signals.
The DASH format has two track densities, ‘Normal’ and ‘Double’. While the DASH 24 channel machine is based on the normal density format, the Sony PCM-3348 adopts the double density format. Audio tracks 1 — 24 are recorded in the same location on tape in both format densities, so that tracks 1 — 24, plus auxiliary tracks, recorded by a Sony PCM-3348 can all be played back on any DASH 24-channel machine, such as a Sony PCM-3324S. Similarly, a PCM-3348 can be used to add tracks 25 — 48 to a tape recorded by a 24-channel DASH machine.
A major advance in record head technology made the 48-channel machine possible. The ‘Thin Film Record Head’, with its related pulse train drive recording circuit, was especially developed for the PCM-3348 and enabled this state-of-the-art recorder to record a total of 52 tracks on a half-inch tape with minimal crosstalk between tracks. The Sony PCM-3348 incorporates an advanced pure crystal ferrite reproduce head of proprietary construction for precise reproduction of all 52 tracks.
Ideally suited for digital audio editing systems and sound sweetening applications in video/audio post-production, the PCM-3348 includes comprehensive synchronisation functions. This allows synchronised operation with composite video, composite sync, black burst, AES/EBU digital 1/0 sync or word sync as an external reference signal.
The Sony PCM-3348 can be controlled from a wide range of external control units via its remote interface connectors, giving enhanced remote-control from the supplied remote controller RM-3348 and other equipment, such as a synchroniser. An optional DABK-3340 REMOTE-4 I/F, which conforms to the SRIF-4 format, allows simple and direct interfacing with an audio mixing console to give a Channel Rec Ready function. A rehearsal or preview function can also be controlled-externally from a synchroniser or mixing console via the REMOTE-I parallel interface.
The RM-3348 remote control unit is supplied with the Sony PCM-3348, providing comprehensive control over all of its functions that are required for studio operations. The PCM-3348 can be completely operated from its integral tape deck control panel and the Sony RM-3348 intelligent remote controller. A dedicated edit mode is included in the RM-3348. This facilitates sophisticated electronic editing, with simple key stroke sequences on up to three Sony RM-3348s controlling their associated PCM-3348s for A/B roll editing. Preview and edit point trimming functions are available for the player and the recorder.
The Sony PCM-3348 incorporates a time code generator and reader. Any format of time code, SMPTE (drop frame/non-drop frame), EBU and FILM, can be accommodated by the Sony PCM-3348. It can regenerate and record the incoming time code locked to the reference video signal, ideally for audio recording in synchronisation with video.
A total of 12 LSI circuits have been developed for the PCM-3348. Their use, together with LSI devices developed for other digital equipment, has reduced the number of signal processing boards to only three. This results in a compact size, the low power consumption of I .2kW and high mechanical reliability.
The addition of a mechanical clutch between the capstan and capstan motor results in an outstandingly fast tape transport and the comprehensive, microprocessor controlled, servo system ensures accurate and stable tape movement at high speeds. This enhanced transport mechanism is mounted on a very rigid diecast chassis which features excellent durability and stability for the tape path components and motors.
In fast forward and rewind modes, the tape is automatically slowed towards the end of the reel to avoid physical damage. The tape end switch can be set so that the tape will stop automatically before the end of the reel to keep the tape from spooling off.
Ease of servicing and adjustment is built into the Sony PCM-3348 design. The tape transport section can be opened up to an angle of 70 degrees for access to the internal circuit boards and rather than having to exchange complete head blocks, each head can be replaced individually. The power supply unit can be removed while still operating because of its long connecting cables.
Both the A/D and D/A conversion circuits feature 2-times oversampling in combination with digital filters. Sony proprietary digital filters reduce the need for a sharp cut off in the analogue low pass filters. As the digital aperture correction characteristics of these digital filters is controlled by software, aliasing noise is reduced and a superior response at high frequencies is achieved. The analogue circuitry design optimises sound quality, even compensating for the non-ideal characteristics of circuit components.
The sampling frequency can be selected to be 44.056kHz, 44.1 kHz or 48kHz. The PCM-3348 can be operated in most digital audio recording/playback applications, ranging from CD mastering to laser disc production and digital video post-production. The Sony PCM-3348 is equipped with an Fs shift mode which allows the 48kHz and 44. 1kHz sampling frequencies to be lowered by O. 1% in playback.
The Sony PCM-3348 is equipped with three digital audio interfaces for direct connection to digital audio equipment:
- 2CH AES/EBU digital 1/0
- 2-CH unbalanced SDIF-2 digital 1/0
- 48-CH balanced SDIF-2 digital 1/0
Two AES/EBU or SDIF-2 channels of digital 1/0 can be assigned to or from any tape track on the PCM-3348.
The Sony PCM-3348 has an Advance Out function which is a convenient to compensate for the signal processing delay which can occur when interfacing with external digital equipment. The pre-delay value is variable in I-sample steps up to a maximum of 256 samples.
Realtime digital ping pong is a feature of the Sony PCM-3348. Up to 48 channels can be simultaneously bounced digitally within the machine, with zero timing and phase errors.
The PCM-3348 provides a stereo sound memory function with enhanced playback features. Up to 20 seconds of full resolution stereo digital audio data can be memorised in the sound memory. Alternatively, it can be used in mono mode, extending the memorised time to 40 seconds. A looping function is included for accurate trimming the start or end point. The digital audio data stored in this sound memory can be reproduced at any CTL address automatically. Reverse playback of the memorised data is also provided.
The integral chase synchroniser allows two modes of time code chase synchronisation with the RM-3348 remote control. The PCM-3348 locks to the incoming time code with subframe accurate offsets. This allows the Sony PCM-3348 to be connected directly to an external VTR for enhanced sound-for picture editing.
- Re-Chase Mode: After locking to the incoming time code, the Sony PCM-3348 will continuously monitor and chase the time code, making it possible to maintain complete synchronisation with the master time code. The tape can be monitored as its speed varies.
- Free-Run Mode: After locking to the incoming time code, the Sony PCM-3348 enters normal playback and is then unaffected by any changes in the external time code.
A convenient punch IN and punch OUT operation is provided on the PCM-3348 when under RMI-3348 remote control. At punch IN and punch OUT points, the digital audio data is electronically processed to give a noiseless and smooth cross fade. The crossfade time is variable in 16 steps from 1 to 370 milliseconds. Punch IN/OIJT points can be designated easily. During auto punch IN/OUT operation, the park point before the start of the pre-roll does not have to be designated by the pre-roll time and can be designated by direct entry from the numeric keys or locate position on the RM-3348.
Accurate and high-speed auto location is provided by the PCM-3348 and the RM-3348 remote control system. Up to 100 points on the tape can be memorised as cue point and trimmed as necessary. The PCM-3348, together with its RM-3348i allows the tape to be advanced or reversed to any cue point. The PCM-3348 provides a convenient rollback function that allows location to a point which is the locate point minus the pre-roll time. Either the zero locate or roll-back function can be selected.
Under control of the RM-3348 supplied remote controller, a PCM-3348 can be operated in perfect synchronisation with two other PCM-3348 or PCM-3324S DASH recorders, providing up to 144 channels of digital audio recording/ reproducing.
The Sony PCM-3348 uses a PWM (Pulse Width Modulation) system for cue track recording and playback, giving a dynamic range of over 60dB. Cue signals recorded on other DASH machine, such as PCM-3324/3324A, with bias recording can be reproduced completely. Variable Speed Playback Ranging Over ±12.5%.
All functions of the Sony PCM-3348 can be controlled from its Sony RM-3348 connected through the D-dub 50-pin REMOTE-3 connector:
- Synchronised operation of two or three DASH recorders
- Sound memory control
- Multiple digital ping pong
- Time code chase synchroniser
- Auto punch IN/OIJT operation 2-CH Digital 1/0 select
- Crossfade time select
- Variable speed playback/variable speed setting-Repeat playback
- Memorising up to 100 cue points
- Recording/reproduction channel setup
- Recording/reproduction channel control
- All input setting
- All repro setting
- Rec disable setting
