The Nakamichi 600 Stereo Cassette Console was a two-head cassette deck designed as part of Nakamichi’s Recording Director Series, and it occupied a distinctive position between domestic hi-fi cassette recording and more serious tape-based production work. The Nakamichi 600 arrived at a time when Nakamichi was already challenging the assumption that the compact cassette was a compromised convenience format, and the Nakamichi 600 was presented as a cassette machine capable of performance figures that had previously been associated more closely with high-quality open-reel tape recorders. The later Nakamichi 600 II would refine this concept further with Nakamichi’s Crystalloy SuperHead and an extended 35Hz to 20kHz response specification, but the original Nakamichi 600 already established the fundamental design approach: high headroom, accurate metering, user calibration, stable transport engineering and a console layout aimed at serious recording use.
The Nakamichi 600 was built around a focused-field crystal permalloy record/playback head. Nakamichi placed major emphasis on the head because, in a two-head cassette deck, the same head must perform both recording and playback duties. This was a critical design challenge, as recording requires deep magnetisation of the tape coating while playback requires accurate retrieval of high-frequency information from very short recorded wavelengths. The Nakamichi 600’s focused-field head was designed to maximise record/playback performance by using the full thickness of the magnetic tape coating while minimising the critical recording zone. This was intended to reduce distortion, improve high-frequency performance and give the deck the headroom needed for demanding programme material.
A major claim of the Nakamichi 600 was its guaranteed frequency response of 40Hz to 18kHz, ±3dB, using SX and EX tapes at a -20dB recording level. For a two-head cassette deck of the period, this was a significant specification. Nakamichi had already achieved wider frequency response in its three-head cassette decks, and the later Nakamichi 600 II would extend the two-head line to a 35Hz to 20kHz specification with EX II and SX tape, but the original Nakamichi 600 was important because it brought much of Nakamichi’s high-performance cassette thinking into a more compact two-head console format.
The Nakamichi 600 also addressed one of the main weaknesses of many cassette decks of the period: limited recording headroom. Rather than setting the meter reference point artificially low or altering meter response to hide distortion, Nakamichi designed the 600 with true peak-reading meters and a high recording level capability. The deck’s meters extended to +7dB, with 0dB referenced to 200nW/m, allowing the recordist to work with higher programme peaks while still monitoring the risk of saturation. The later Nakamichi 600 II retained the same general philosophy of peak-reading metering and expanded scale monitoring, showing how central this approach was to the 600 series.
One of the most distinctive features of the Nakamichi 600 was its I.M. Suppressor circuitry. This system was designed to reduce the saturation and distortion encountered at high recording levels during playback. Nakamichi described the system as using the predictable saturation and distortion characteristics of tape to apply compensation, increasing usable dynamic range and improving the signal-to-noise ratio. In the specifications, the Nakamichi 600 was rated at better than 60dB signal-to-noise ratio with Dolby in, SX tape and weighted RMS measurement, rising to better than 68dB at 400Hz, 3% THD, weighted RMS, with the I.M. Suppressor engaged.
The Nakamichi 600 included Dolby noise reduction, but its performance with Dolby depended heavily on the deck’s wider engineering design. Nakamichi argued that Dolby noise reduction required accurate record and playback behaviour to work properly. A deck with insufficient high-frequency headroom could cause mistracking, making Dolby playback appear to reduce high-frequency content or alter the sound. The Nakamichi 600 was guaranteed to meet its frequency response specification with or without Dolby engaged, which reflected Nakamichi’s view that Dolby itself was not the issue, but that the deck had to be accurate enough for Dolby to operate correctly. The later Nakamichi 600 II continued this emphasis, with a wider 35Hz to 20kHz specification stated with Dolby either switched on or off.
Calibration was central to the Nakamichi 600’s design. The deck included a built-in 400Hz test tone and record level calibration controls, allowing the user to adjust the machine so that a tone recorded at 0dB would play back at 0dB within a ±1dB tolerance. This was especially important for correct Dolby operation because level mismatch between recording and playback could cause audible colouration. The Nakamichi 600 II followed the same basic principle, retaining built-in calibration facilities and making calibration a defining part of the 600 series rather than an afterthought.
The Nakamichi 600 also provided user-adjustable bias controls on the front panel. During the 1970s, cassette tape formulations were developing quickly, and no single fixed bias setting could be ideal for every tape type. By giving the user direct access to bias calibration, the Nakamichi 600 allowed more accurate matching to different tape formulations. This gave the deck a level of flexibility that separated it from simpler cassette machines, and it foreshadowed the more refined calibration approach of the Nakamichi 600 II, which added a built-in 10kHz bias oscillator to assist with bias adjustment.
Another advanced feature was independent bias and equalisation switching. The Nakamichi 600 allowed users to combine settings in ways that were not normally available on cassette decks. For example, Nakamichi described the possibility of using 70 microsecond equalisation with EX tape rather than the more conventional 120 microsecond setting, allowing the user to trade some high-frequency headroom for an improved signal-to-noise ratio. This made the Nakamichi 600 a more experimental and flexible recording tool, particularly for users who understood the interaction between tape formulation, bias, equalisation, headroom and noise performance. The later Nakamichi 600 II retained this concept of independent bias and equalisation selection, making it one of the clearest points of continuity between the two models.
Phase correction circuitry was also included in the Nakamichi 600. Nakamichi described phase shift as an accepted but undesirable by-product of tape recording, particularly when harmonics shifted in phase relative to a fundamental frequency. The phase correction circuitry was designed to reduce colouration caused by phase errors and to help the Dolby and I.M. Suppressor circuits process the signal more accurately. The later Nakamichi 600 II also used phase correction circuitry, and this again shows how the original Nakamichi 600 established a technical framework that Nakamichi continued to develop in the revised model.
The Nakamichi 600 featured a built-in MPX filter for FM stereo recording. When recording FM stereo broadcasts, the 19kHz pilot signal could cause Dolby circuitry to mishandle high-frequency programme material. The front-panel MPX filter switch allowed the user to engage filtering when needed, preventing the pilot tone from interfering with Dolby noise reduction. This was a practical feature for users recording radio broadcasts, and it reflected the deck’s role as a serious cassette recorder rather than simply a playback component.
Mechanically, the Nakamichi 600 used a DC servo motor drive system to maintain constant and accurate speed regardless of line voltage or frequency fluctuations. The deck was specified at less than 0.12% weighted peak wow and flutter, or less than 0.08% weighted RMS. Nakamichi specifically favoured weighted peak measurement, arguing that it correlated more realistically with the ability of the human ear to detect wow and flutter. The later Nakamichi 600 II carried forward very similar transport performance figures, reinforcing the stability of the basic 600-series mechanical concept.
The console form factor was one of the most recognisable aspects of the Nakamichi 600. Its angled front panel placed the controls and meters in a position suited to table-top operation and monitoring. Nakamichi described this as a human-engineered operating angle, and the design made the deck visually distinct from flat-front domestic cassette decks. The later Nakamichi 600 II kept the same broad console identity, with its sloped panel, front-mounted controls and precision recording layout, making the original Nakamichi 600 the model that established the physical character of the series.
Operational convenience was also given careful attention. The Nakamichi 600 included a memory tape counter, allowing the user to set the counter to 000 at the start of a recording and then rewind automatically to that point after recording. It also included separate left and right input level controls plus a master input level control, so once channel balance was set, the overall recording level could be adjusted for both channels together. This also made fade-ins and fade-outs easier to perform. The deck could also be used for unattended recording or playback with an external timer, adding practical flexibility for FM recording or scheduled playback.
The Nakamichi 600 omitted built-in microphone inputs, but it was intended to integrate with Nakamichi’s wider recording system. Live recording could be handled using the Nakamichi 610 Control Preamplifier, which allowed stereo mixing of five inputs and included low-impedance microphone inputs. Nakamichi positioned the combination of the 600, 610 and high-quality microphones as a live cassette recording system capable of serious results. This system approach remained important to the 600 series, and the later Nakamichi 600 II brochure also positioned the deck as part of a broader live recording setup using companion Nakamichi mixing and control products.
Internally, the Nakamichi 600 was presented as a high-reliability design, with an emphasis on reduced hand-wiring, complex but orderly circuitry and a transport mechanism developed through multiple generations of refinement. The deck’s exterior was described as functional as well as attractive, and the specifications listed a 400mm wide, 170mm high and 237mm deep chassis with an approximate weight of 6.5kg. The combination of a solid console layout, front-panel calibration and serious signal-path engineering made the Nakamichi 600 one of Nakamichi’s most distinctive early cassette machines.
As a retrospective product, the Nakamichi 600 is best understood as the foundation of the 600-series concept rather than simply the model before the Nakamichi 600 II. The original Nakamichi 600 introduced the console layout, focused two-head engineering, user-accessible calibration, high-headroom recording philosophy, peak-reading metering and system-based recording approach. The Nakamichi 600 II later developed these ideas with updated head technology, a wider frequency response claim and revised calibration facilities, but the original Nakamichi 600 had already defined the purpose of the range: to make the compact cassette behave less like a convenience medium and more like a controlled, high-performance recording format.
Features
- Two-head cassette console design
- Focused-field crystal permalloy record/playback head
- I.M. Suppressor circuitry
- Dolby noise reduction
- Phase correction circuitry
- Built-in MPX filter for FM stereo recording
- Built-in 400Hz test tone
- Record level calibration controls
- User-adjustable bias calibration controls
- Independent bias and equalisation switching
- Peak-reading meters with 47dB range
- Memory tape counter
- Separate left and right input level controls
- Master input level control
- DC servo motor drive system
- Unattended record or playback using an external timer
- Angled console control panel
- DIN in/out connection
- Designed for use with the Nakamichi 610 Control Preamplifier for live recording