Introduced in 1976, the Akai GXC-730D was a front-loading stereo cassette deck designed for automatic reverse recording and playback. Its centrally positioned GX record and playback head operated in both tape directions, supported by two erase heads and a four-pole hysteresis synchronous motor. The Akai GXC-730D combined automatic and manually selected reverse modes with memory winding, solenoid-operated transport controls, Dolby noise reduction, Akai’s ADR system and facilities for normal, chromium dioxide and ferrichrome tape.
The Akai GXC-730D used a four-track, two-channel stereo recording system operating at the standard cassette speed of 4.75cm/s. Its principal GX head handled recording and playback in both forward and reverse directions, allowing the deck to reproduce and record both sides of a cassette without requiring the tape to be removed and turned over manually.
The GX record and playback head was positioned centrally between two erase heads. This arrangement provided the head configuration required for recording in either direction while retaining dedicated tape erasure before the selected recording pass. Akai’s GX head construction combined glass and crystal ferrite materials. The head was intended to provide long service life and stable performance while supporting recording and playback in both directions.
Illuminated direction indicators showed whether the transport was operating forwards or in reverse. A front-panel reverse selector allowed the operator to choose one-way, one-cycle or continuous operation. In one-way mode, the deck recorded or played only in the selected direction. Forward operation was selected through the forward transport key, while reverse operation was selected through the reverse key.
One-cycle mode allowed the Akai GXC-730D to operate in the forward direction and then reverse automatically at the end of the tape. Playback stopped after the reverse pass, while recording could also be configured to complete a single forward and reverse cycle. Continuous mode allowed playback to alternate repeatedly between the forward and reverse directions until the Stop control was pressed. During recording, the deck could be arranged to reverse at the end of the first pass and continue recording in the opposite direction.
The Akai GXC-730D incorporated soft-touch solenoid direct-function controls. Transport commands were applied through individual keys for record, rewind, reverse play, stop, forward play and fast forward. The direct-function system permitted one operating mode to be selected from another without first pressing Stop. During playback, pressing either fast-wind key initiated tape movement in the selected direction. During recording, pressing a direction key enabled the deck to reverse and continue recording.
Automatic play could be initiated after fast forward or rewind by pressing the Play key together with the appropriate fast-wind control. At the end of the winding operation, the transport entered playback automatically. A self-locking Pause control suspended tape movement during recording or playback. Pressing the control again released Pause and resumed the selected transport mode.
The memory-wind system operated with the mechanical tape counter. After setting the counter and engaging the Memory control, the deck could stop automatically when the stored position was reached during fast forward or rewind. The memory system could also be combined with the Play key. This allowed the Akai GXC-730D to locate the selected counter position and begin playback automatically after winding.
Akai equipped the GXC-730D with its ADR automatic distortion-reduction system. This system was intended to reduce recording distortion and improve recorded performance across the audio band. The tape selector included settings for low-noise, chromium dioxide and ferrichrome tape. Selecting the appropriate formulation established the recording and playback equalisation required for the cassette being used.
Rear-panel recording-level calibration controls allowed the Akai GXC-730D to be adjusted more precisely for the selected tape formulation. This provided an additional method of matching the recording system to variations between cassette types. The deck incorporated Dolby noise reduction for recording and playback. During recording, Dolby processing raised lower-level programme information before it was placed on the tape. Complementary processing during playback restored the programme level while reducing audible tape noise.
A switchable limiter was provided to control excessive recording levels. This was particularly useful when recording from microphones at close range, where sudden increases in level could otherwise cause overload and distortion. The input selector separated the microphone and line-input circuits. This allowed the appropriate signal path to be chosen for the source in use and reduced unnecessary noise from an unused input section.
Separate left and right recording-level controls allowed the two stereo channels to be adjusted independently. A separate output-level control matched the deck’s playback level to the connected amplifier or other equipment. Twin illuminated VU meters displayed the left and right recording and playback levels. Their large scales provided clear level indications, while a separate peak-level warning lamp illuminated at +7dB to identify excessive input peaks.
The front panel included separate left and right microphone sockets together with a headphone output. The headphone connection allowed direct monitoring during recording and private listening during playback. Line and DIN connections were provided for integration with amplifiers and other audio equipment. The line input accepted a nominal signal of 70mV, while the microphone inputs had a sensitivity of 0.3mV.
Frequency response was specified from 30Hz to 14kHz within ±3dB using low-noise tape, from 30Hz to 16kHz within ±3dB using chromium dioxide tape and from 30Hz to 17kHz within ±3dB using ferrichrome tape. Signal-to-noise ratio was specified at better than 50dB with low-noise tape, measured through the tape at a peak recording level of +3 VU. Dolby noise reduction provided an improvement of up to 10dB above 5kHz.
Wow and flutter was rated at less than 0.08% weighted RMS according to NAB measurement and 0.24% according to DIN 45507. Distortion was specified at less than 1.5% at 1kHz and 0 VU using low-noise tape. Fast-forward or rewind time was approximately 70 seconds with a C-60 cassette. The four-pole hysteresis synchronous motor powered the transport for recording, playback and fast winding.
The Akai GXC-730D was housed in a substantial cabinet with a brushed aluminium front panel and timber-finished outer enclosure. Its cassette compartment occupied the left side, with the direction controls, counter, metering and recording adjustments arranged across the remaining front panel. Measuring 175mm high, 440mm wide and 302mm deep and weighing 12kg, the Akai GXC-730D was a large cassette recorder whose construction reflected the additional mechanism and control circuitry required for bidirectional recording.
The Akai GXC-730D represented Akai’s application of automatic reverse operation to both recording and playback. Its GX head system, multiple reverse modes, memory winding, solenoid controls and comprehensive recording facilities made it one of the company’s more elaborate cassette decks of the mid-1970s.
Features
- Automatic reverse recording and playback
- GX record and playback head operating in both directions
- Separate erase heads for forward and reverse recording
- One-way, one-cycle and continuous reverse modes
- Soft-touch solenoid direct-function transport controls
- Memory winding with automatic stop or playback
- Akai ADR automatic distortion-reduction system
- Dolby noise reduction
- Low-noise, chromium dioxide and ferrichrome tape selection
- Limiter and microphone or line-input selection
- Twin illuminated VU meters with +7dB peak warning
- Separate left and right recording-level controls