Introduced in 1976, the Tandberg TCD 330 was a three-head stereo cassette deck designed to bring facilities normally associated with open-reel recorders to the compact cassette format. It combined separate recording and playback heads, direct off-tape monitoring, a dual-capstan transport, Dolby B noise reduction, adjustable recording-head azimuth and comprehensive recording controls within a cabinet that could be operated horizontally, vertically or mounted on a wall.
The Tandberg TCD 330 used three magnetic heads for erase, recording and playback. Separating the recording and playback functions allowed the operator to monitor the signal directly from the tape while a recording was being made. This provided an immediate comparison between the incoming source and the recorded result rather than requiring the cassette to be rewound before checking the recording.
A front-panel Monitor control selected between the source signal and the signal reproduced from the tape. With the control in the Source position, the operator heard the programme before it reached the cassette. Selecting Tape routed the playback-head signal to the outputs, allowing the recording to be checked while it was still in progress. The monitoring system could be used through an amplifier and loudspeakers or through headphones connected directly to the deck.
The transport employed two capstans, one positioned before the heads and the other after them. These capstans maintained tension across the section of tape passing the recording and playback heads. Tandberg stated that the arrangement helped isolate the active tape path from irregularities created by the cassette shell, including variations caused by the pressure pad, tape guides and internal friction.
The tape mechanism was designed to reduce the number of moving components. Many conventional mechanical functions were replaced by electronic switching and electromagnetic control, with the transport operated through large front-panel buttons. Controls were provided for Record, Rewind, Stop, Wind and Play, together with Pause, Record Preset and cassette ejection.
The Record Preset system allowed the recording circuitry and level controls to be prepared before the transport entered record mode. This enabled the input level to be set and monitored before recording began. Recording could then be started by pressing Play while the Record Preset control was engaged.
A flying-start facility allowed direct transfer from playback into recording without stopping the tape. By holding the Play control and pressing Record, the deck could change from playback to recording while the cassette continued to move. This was useful when inserting new material into an existing programme.
The Tandberg TCD 330 incorporated a memory system linked to the mechanical tape counter. The Memory function operated during rewind and stopped the transport when the counter reached 000. This could be used to return automatically to the beginning of a recorded section after the counter had been reset at the desired starting point.
The cassette compartment was located beneath a top-mounted cover. The cassette was inserted with the full reel positioned towards the Tandberg name on the front panel, after which the compartment was closed manually. The Eject control opened the compartment only when the transport was in Stop.
The deck was designed for use with normal and chromium dioxide cassette formulations. A tape selector altered the recording and playback conditions for special tapes marketed under designations including chromium dioxide, chrome and similar high-performance formulations. For ordinary low-noise and standard tapes, the selector remained in the Normal position.
Dolby B noise reduction was included for compatible recording and playback. During recording, the Dolby circuit increased selected low-level high-frequency information before it was placed on tape. During playback, the corresponding reduction process restored the programme balance while reducing audible tape noise.
The Dolby system could be switched independently for recording and playback according to the cassette being used. A recording made with Dolby processing was intended to be reproduced with Dolby engaged, while tapes recorded without it were normally played with the system switched off.
An MPX filter was fitted for recording FM stereo broadcasts. The filter reduced the 19kHz multiplex pilot signal that could otherwise interfere with the Dolby noise-reduction circuitry. Tandberg advised leaving the filter switched on for FM stereo recording and switching it off for other programme sources where its operation was unnecessary.
The Tandberg TCD 330 also provided a rear-panel input sensitivity selector. This allowed the input stage to be matched to the output level of the connected amplifier, receiver or other source equipment. The selector could be changed with a screwdriver to obtain a suitable operating range for the front-panel input-level controls.
Independent left and right input-level sliders were provided for setting the recording level. Two illuminated analogue meters displayed the signal in each channel. The operator adjusted the sliders so that normal programme material reached the recommended meter level without excessive movement into the overload region.
Tandberg provided different recording-level recommendations according to the tape being used. Special tapes could accept higher recording levels than ordinary low-noise formulations, while speech and other material with relatively predictable peaks could be recorded differently from highly dynamic music. The meters were intended to show programme peaks rather than only average level.
The recording controls also allowed the left and right channels to be adjusted independently. For mono recording, either microphone input could be used, with the corresponding channel control setting the recording level. A Mono control allowed both channels to be combined when required for mixed speech and music programmes.
Two front-panel microphone sockets accepted low-impedance microphones rated between 100Ω and 600Ω. The left microphone connected to the left recording channel and the right microphone to the right channel. When microphones were inserted, the corresponding programme input was automatically disconnected.
The deck could therefore be used as a microphone amplifier without necessarily recording. Microphones connected to the front panel could be monitored through headphones or passed through the TCD 330 to an external amplifier and loudspeakers. The left and right signals could remain separate or be combined using the Mono function.
Separate left and right output-level controls governed the signal delivered to the headphones and line outputs. These controls allowed the monitoring volume to be adjusted without changing the recording level. When connected to an amplifier, the deck’s output controls could be set to suit the input sensitivity of the receiving equipment.
A front-panel headphone socket allowed direct monitoring without an external amplifier. The headphone level was governed by the output controls. Tandberg specified the use of headphones with an impedance of 8Ω or higher.
The TCD 330 could be connected to an amplifier or radio receiver through separate input and output cables. The Tape Out connections from the amplifier fed the deck’s inputs, while the TCD 330 outputs returned the playback signal to the amplifier’s tape-monitor input. A five-pin DIN connection could also be used with compatible European equipment.
Direct copying between two cassette recorders was supported. A second deck could be connected through the line input and output sockets, allowing recorded material to be transferred from one cassette to another. The Dolby settings had to be selected according to whether the original tape had been Dolby encoded and whether the copy was intended to carry the same encoding.
A built-in test oscillator assisted with recording-head azimuth adjustment. Tandberg provided an external adjustment screw that controlled the vertical position of the recording head. The test signal was recorded and monitored through the playback head, allowing the operator to adjust the record-head position for the strongest and most stable indication.
The azimuth adjustment was intended to compensate for small variations between cassette shells and tape paths. Correct alignment was particularly important at high frequencies, where even a slight angular difference between the tape and recording-head gap could reduce performance.
Tandberg recommended adjusting the recording-head azimuth before each recording, regardless of whether the cassette was new, previously used or partly recorded. Once adjusted for a particular cassette, the setting did not need to be changed again unless another tape was inserted.
The procedure used the Test Tone control, Record Preset, Record and Monitor functions. A built-in indicator showed when the head alignment was correct, removing the need for external test equipment. The deck could therefore be optimised for the individual cassette from the front panel.
The TCD 330 included a remote-control connection on the rear panel. An optional Tandberg Remote Control Unit could operate Record, Play, Rewind, Stop and Wind from a distance. The main transport buttons remained operational while the remote unit was connected.
The cassette deck could be placed horizontally, stood vertically using its integral feet or mounted on a wall. For vertical operation, the feet were released and positioned to support the cabinet. Wall mounting used two screws fitted into the wall, with the rear of the deck engaging over them.
A removable rear cover concealed the connecting cables when the deck was installed away from conventional shelving. Tandberg cautioned that the cabinet should not be lifted by this cover.
Routine maintenance centred on cleaning the tape path. Tandberg recommended regularly cleaning the heads, capstans, pinch rollers and surrounding tape-contact surfaces. The cassette-compartment cover could be removed to provide access, although the adjustment screws were not to be disturbed during cleaning.
The Tandberg TCD 330 combined three-head recording, off-tape monitoring, dual-capstan tape handling, manual azimuth alignment and electronic transport control in a cassette deck designed for detailed user adjustment. Its flexible mounting arrangements, microphone facilities, remote-control provision and comprehensive monitoring system made it suitable for both domestic recording and more specialised applications.
Features
- Three-head stereo cassette recording and playback
- Separate erase, recording and playback heads
- Direct off-tape monitoring during recording
- Source and tape monitor selection
- Dual-capstan tape transport
- Electronic transport controls
- Record Preset function
- Flying start from playback into recording
- Pause control
- Mechanical tape counter
- Counter-linked memory rewind stop
- Dolby B noise reduction
- FM multiplex pilot-tone filter
- Normal and special tape selection
- Built-in recording-head azimuth test system
- Front-panel recording-head azimuth adjustment
- Independent left and right input-level controls
- Dual illuminated analogue recording-level meters
- Independent left and right output-level controls
- Two low-impedance microphone inputs
- Mono channel-combining function
- Front-panel headphone output
- Adjustable rear-panel input sensitivity
- Line and five-pin DIN connections
- Direct cassette-to-cassette copying
- Optional wired remote control
- Horizontal, vertical or wall-mounted operation
- Removable cassette-compartment cover for cleaning