Aiwa AD-F660 Cassette Deck Review

The Aiwa AD-F660 cassette deck offers Dolby-B and Dolby-C noise reduction as well as Dolby-HX Professional high-frequency headroom extension. A three-head, dual-capstan deck, the AD-F660 has a horizontally mounted control panel, and among its features is an automatic head-demagnetizing circuit that is activated for 1-1/2 seconds each time the deck is turned on.

The AD-F660’s separate record and playback head sections allow instantaneous comparison between source and recorded signals. The two heads, which are in a common case (with a spacer between them), are made of hard permalloy with a Sendust facing. The dual capstans are belt-driven by a d.c. servomotor and have a special “Micro-Grain” surface to prevent tape slippage between the capstans and pinch-rollers. A second d.c. motor turns the reel hubs. All transport modes are solenoid-operated, and the play, record, pause, and record-mute pushbuttons have LED indicators.

The AD-F660’s illuminated cassette well is visible through the clear door, which is removable for head cleaning and capstan demagnetizing. Sensor switches within the cassette well detect tape type and automatically set the proper equalization and bias levels. In addition, there is a bias-optimizing control for ferric and CrO2-type tapes.

Besides the transport pushbuttons, the control keyboard contains one long-throw (4-inch) record-level slider and six small pushbuttons for selecting counter and memory options. The four-digit electronic counter can be set to read either in conventional, arbitrary units or in minutes and seconds remaining on a tape side (during fast winding it displays minutes only). The memory modes include not only the usual rewind/stop and rewind/play but also the option of continually repeating a section within a tape. The music scan feature permits skipping ahead or back to the start of a selection and beginning playback from that point. The intro play feature operates similarly except that it plays only the first 8 seconds of the music and skips to the next starting point and repeats the process if the user doesn’t press the play button. Both music scan and intro play utilize the blank spaces between selections, and the AD-F660 has a button to insert the spaces when you are recording your own tapes.

Record and playback levels are shown by a twelve-segment-per-channel LED scale calibrated from —20 to +10 dB, with the Dolby-level marking at +2 dB. The 0-, +1 -, and + 2-dB LED’s are yellow, with red above and green below these levels. Recommended maximum peak-level inputs are marked at +4, +6, and +8 dB for ferric, chrome, and metal tapes, respectively, and the highest illuminated segment remains on for approximately 2 seconds to ensure that it will be noticed. Front-panel LED’s indicate tape or source monitoring, tape type, noise-reduction system in use, etc. The front panel also contains a record-balance control, a headphone jack, and a switch for external timer control.

The rear panel of the AD-F660 has the usual input and output jacks, a connector for an optional infrared remote control, microphone jacks, an FM multiplex switch, and a two-position headphone-volume switch. The deck measures 16-5/8 inches wide, 4-3/8 inches high, and 11-1/4 inches deep, and it weighs just over 12 pounds. Price: $395.

Laboratory Measurements

The playback frequency response of the AD-F660 for both normal (120-microsecond) and high-bias/metal (70-microsecond) tapes was almost ruler-flat, measuring within + 0.5, —1 dB over the 31.5- to 18,000-Hz range of our IEC standard (BASF) calibrated tape.

Aiwa supplied the three TDK tapes—D (ferric), SA (high-bias), and MA (metal)— used in the factory setup of our sample deck. We also tested it with a variety of other formulations, including Sony EHF, TDK AD, and Maxell UDXL-I (ferries); Sony UCX-S, Memorex HB-II, and BASF Pro II (CrO2-types); and Fuji FR and Maxell MX (metal). By using the fine-bias adjustment we obtained almost identical curves with all these formulations. For our graphs and measurements, however, we substituted the premium Maxell UDXL-I for the standard TDK D because it yielded a somewhat better signal-to-noise ratio (S/N). With all three tape types the frequency response at — 20 dB was very wide, being down by 3 dB at about 25 and 19,000 Hz. At the official IEC 0-dB level of 250 nanowebers/meter, nearly 4 dB above the AD-F660’s own 0-dB indication, the Dolby-HX Professional system extended the treble overload point somewhat beyond what we would expect, but since the system could not be switched out we could not measure its effect precisely. As the uppermost curve at the 0-dB level shows, however, using metal tape with the Dolby-C noise-reduction system (which lowers the high-frequency record pre-emphasis) produced a response that was flat almost all the way to 18,000 Hz.

The third-harmonic distortion of a 315-Hz tone recorded at the IEC 0-dB level measured 0.22, 0.89, and 0.26 per cent for Maxell UDXL-I, TDK SA, and TDK MA, respectively, and the recorded level on these three tapes could be raised by 5.1, 4.1, and 8.6 dB before 3 per cent distortion was encountered. With reference to the 3 per cent point, the signal-to-noise ratios, unweighted and without noise reduction, measured 54.4, 56.1, and 60.5 dB with UDXL-I (ferric), SA (high-bias), and MA (metal), respectively. With the customary IEC A-weighting and Dolby-B, the S/N’s improved to 67.6, 69.2, and 73.9 dB. With the same weighting and Dolby-C, the ratios improved to 73.9, 75.6, and 80.1 dB, which is astonishingly good performance.

Wow-and-flutter figures were no less impressive, measuring only 0.019 per cent (WRMS) and 0.038 per cent (DIN peak-weighted) with our Teac MTT-111 test tape. Both tape speed and Dolby-level calibration were exact, and frequency-response errors introduced by either Dolby-B or Dolby-C at levels of 0, —20, and —40 dB amounted to less than 1 dB throughout the entire range of the deck. Line-level sensitivity was 59 mV for a 0-dB output of 0.41 volt. The microphone inputs required a level of 0.3 mV for a 0-dB reading, and they overloaded at 33 mV, an average figure for home cassette decks.

Comment

Its combination of top performance, tasteful styling, and an array of useful features for under $400 makes the Aiwa AD-F660 a bargain hunter’s delight. We did miss a playback output-level control, the record-indicator light is difficult to see when you are standing directly in front of the deck, and neither the high nor low setting of the headphone volume switch was quite right for our particular headphones. And we would have felt safer with a built-in calibrated oscillator for bias optimization— even though we found that the three-head design of the AD-F660 enabled us, using low-level FM hiss as a signal source, to optimize the bias by ear very nearly as accurately as with our lab generator. (Some of the features we missed on the AD-F660 are available on Aiwa’s next models up, the AD-F770 and the AD-F990.) But we cannot fault the AD-F660 either sonically or in terms of ease of operation.

We had no way of testing the automatic head demagnetizer, but we find the idea an interesting one. The well-spaced controls worked smoothly, and although the minutes-and-seconds mode of the electronic counter does not have the accuracy of a clock, we found it extremely useful.

On prerecorded materials the AD-F660 was exceptionally close to our reference deck. For serious recording the difference between Dolby-B and Dolby-C was very apparent, but that is hardly surprising. When using our most demanding test source—a digital Compact Disc player—we found that metal tape was required to capture the full high end at high signal levels and that if we played the music at nearly ear-shattering levels some hiss could be made audible even with Dolby-C. But the clarity that characterizes digital discs also characterized the tape copies we recorded and played on the AD-F660. Indeed, our cassettes sounded so similar to the original CD’s in this respect that we are tempted to say they were indistinguishable. Semantic niceties aside, the Aiwa AD-F660 is clearly in a league with the best.

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