Aiwa AD-F780 Cassette Deck Review

The new Aiwa AD-F780 cassette deck is designed for the audiophile who wants a number of advanced features at a medium price point. In addition to the usual Dolby B and Dolby C noise-reduction systems, this three-head, dual-capstan deck incorporates both the Dolby HX Pro headroom-extension system and user-adjustable bias and tape-sensitivity adjustments. The headroom-extension system operates automatically to control the recorder’s bias current. The effect is to prevent high-level high frequencies from overloading the tape, and it would be a fair estimate to say that at high recording levels Dolby HX Pro adds nearly half an octave of usable treble response—with no ill effects that we have been able to discover.

The record and playback heads in the AD-F780 are separate, although, as is customary, they are contained within a single casing. Separate heads permit the user to make an immediate comparison between the original sound source and the taped result. The closed-loop, dual-capstan drive system is belt-coupled to a DC servomotor. A second DC motor is used to turn the take-up and supply reels.

The cassette-well door mechanism is unusual in that it contains a spring-loaded plate, called an Anti-Modulation Tape Stabilizer, that exerts some additional pressure to hold the cassette tightly in place. According to Aiwa, this reduces vibrations in the cassette shell. While we had no way to test its effectiveness for this purpose, we did find that it eliminated all label visibility and slightly impeded access to the tape heads and capstans for cleaning. The rear illumination inside the cassette well made it possible to estimate the amount of tape on each reel, however, and we were happy to find that the AD-F780 automatically takes up any tape slack when a cassette is inserted.

Both the four-digit tape counter and the tape-level indicators use fluorescent displays. The counter registers tape-hub revolutions only; it does not show the elapsed or remaining time. The level indicators have twelve peak-reading segments per channel and are calibrated from — 20 to +10 dB. As the numbers on the display are too small to be useful, the two-color presentation (blue below 0 dB, red above) is important in use.

The Aiwa AD-F780 provides front-panel, user-adjustable bias and sensitivity controls. As there are no built-in test tones or metering, however, these adjustments must be made by ear, using a source such as low-level fm interstation hiss. A color-coded guide for setting the bias for various brands of tape is supplied on the top front edge of the deck.

The transport functions are actuated by light-touch solenoid controls. Slide switches are used to select Dolby B, Dolby C, or no noise reduction, memory stop or repeat, and external-timer operation. Pushbuttons are supplied for tape/monitor switching, record mute, and multiplex-filter defeat. Large concentric record-level knobs for the two channels allow adjustment for channel balance. No playback level control is provided either for the main outputs or for the headphone output.

The Aiwa AD-F780 measures 17 inches wide, 5 inches high (including its large mounting feet), and 12-1/2 inches deep, and it weighs approximately 11-1/4 pounds.

Lab Tests

Measured with our ferric and CrO2 IEC-standard BASF test tapes, the playback frequency response of the AD-F780 was very flat. It deviated by less than ± 1 dB from 31.5 to 12,500 Hz and dropped off smoothly above that to —2.5 dB at the 18,000-Hz upper limit of the test tapes.

For checking overall record-play-back response we used “center-line” samples of TDK AD (ferric), TDK SA (high bias), and TDK MA (metal). We use the same tapes and standard levels consistently, so readers can compare test reports from different issues of Stereo Review. As can be seen from the accompanying graphs, the low-frequency performance of the AD-F780 was excellent: There is less than a 2-dB drop all the way down to 20 Hz, and there are no low-frequency “head bumps” of consequence.

At the high-frequency end, response at the IEC-standard 0-dB level of 250 nwb/meter fell off to — 6 dB at 12,000 Hz with the ferric and high-bias tapes. On machines without Dolby HX Pro this point would normally be reached at approximately 8,000 Hz. With HX Pro the metal tape reached 19,000 Hz before its response fell to halfstrength ( — 6 dB) at this level. Switching in Dolby C, which uses less record treble pre-emphasis, extended 0-dB response to 18,000 Hz. At the — 20-dB level normally used for measuring record-playback response, the two conventional tapes were within +0.5, —2.5 dB out to 18,000 Hz, and the metal tape made it to 20,000 Hz. This is very good performance for any cassette deck and especially commendable for one in the price range of the Aiwa AD-F780.

Our wow-and-flutter measurements of 0.075 percent (DIN peak-weighted) and 0.037 percent (WRMS), though very close to Aiwa’s specs, were not quite so impressive. Signal-to-noise ratios (S/N) were very good, however. The fact that the S/N’s for metal tape were not significantly better than those for ferric was slightly disappointing, but not unexpected in a deck at this price.

Tape sensitivity and output levels were entirely normal, and Dolby tracking error was commendably low. High-speed winding times were slightly better than average. The deck did run slightly fast (+0.87 percent), but since I do not have absolute pitch, I did not find the effect audible.

Comments

Although it is easy to operate in a couple of respects, the AD-F780’s human engineering could stand improvement. The solenoids that control the transport functions clunk surprisingly loudly, especially when a tape is first loaded into the machine. The numbers on the tape-level indicators are impossibly small, as are the markings that identify the led indicators for Dolby B, Dolby C, and tape type.

Sonically, on the other hand, we have few faults to find. With Dolby C, the signal-to-hiss ratio was good, and the sonic imaging was very good. Nor could we fault the clarity except in one respect. While we did not detect any wavering of pitch with musical sources (we did with pure test tones, where it is always audible), the relatively high wow-and-flutter of the AD-F780 did detract slightly from the open, transparent character of the sound. We did not judge this to be a serious audible defect, however, and especially in view of the price, we found the overall quality of the Aiwa AD-F780 to be very high indeed.

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