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Frequency Response: 25 Hz to 16 kHz, to 17 kHz with CrO2, to 19 kHz with metal tape.
Harmonic Distortion: 0.7%.
Signal/Noise Ratio: 60 dB.
Input Sensitivity: Mike, 0.25 mV; line, 70 mV; DIN, 2.0 mV.
Output Level: Line, 410 mV; headphone, 1.3 mW at 8 ohms.
Flutter: 0.035% wtd. rms; 0.11% wtd. peak.
Wind Times: 80 seconds for C-60.
Dimensions: 17.3 inches (440 mm) W x 4.6 inches (118 mm) H x 12.2 inches (309 mm) D.
Weight: 19 lbs. (8.6 kg).
801 West Artesia Blvd., Compton, Cal. 90224.
The Akai GX-F66RC is a multi-feature cassette deck which offers auto-reverse record/play, a sophisticated program system, Dolby C noise reduction, and a number of other items. The front panel is an attractive brushed aluminum with easy-to-read black designations. There are quite a few pushbuttons to go with all the functions, but there is relatively little confusion for the user who takes time to read instructions. The cassette-well door opens smoothly with a push of the large "Eject" button, just to the door's left. The timer-start slide switch ("Rec/Off/Play") is below that and above the "Power" switch. Below the cassette-compartment door are large double-arrows: One set at the left to indicate reverse mode, and a set on the right for forward mode.
Once the deck is put into record or play in one direction, the corresponding green arrows are brightly illuminated. Even if the deck is stopped or put into fast wind, the arrows stay on, providing an excellent reminder of the planned direction of record/play.
The tape-motion light-touch buttons have very helpful, built-in indicators, with the exception of stop and "Auto Mute." The sophisticated logic adds such niceties as flashing indicators to show what is called for next: Flashing "Play" when in "Pause," and "Rec" when in "Auto Mute." When the latter function is used, there will be an automatic muting for four seconds, and then the deck goes into "Pause." Longer blank spaces can be obtained by simply holding the button in longer, and "Rec" will flash at one second intervals, which makes accurate timing quite easy.
In the same row with the transport control buttons are two self-indicating button switches which can initiate two interesting and helpful processes. "Intro Scan" sets the deck for fast wind to the beginning of each piece on the tape, one after another, playing just the first ten seconds before fast winding to the next. "Blank Scan" puts the deck into fast wind to the end of what is already recorded. At that point, the deck goes into record mode for four seconds and then into "Pause" in preparation for 'the next recording. Both of these functions work in either direction, handling all of the interrelated tasks automatically-features that should be very useful to most.
A fairly bright four-digit LED display is used for the tape counter or RPSS (Random Program Search System). The "Memory" and "Reset" switches work in normal fashion.
There is also a "Rec Cancel" pushbutton which stops recording, rewinds the deck to counter zero, records a four second blank space, and goes into pause. It might be noted here that by holding in "Play" and pushing the corresponding return-wind button, the deck will fast wind to counter zero and automatically go into play. Pushing "Program" prepares the deck's logic for receiving instructions for RPSS. There are three program entry modes: "SEQ" for sequential playing of selections regardless of entry order, "Random" for playing selections in any order and "Skip" for entering the selections to be skipped, much faster if most of the pieces are to be played. Up to 20 individual selections, for a program total up to 99 items including repeats, and the program itself can be entered to repeat up to 99 times.
The flexibility of the scheme is further enhanced by the fact that RPSS treats the A and B sides of the tape as just one long tape that can be programmed. There is, of course, a ten-key number-entry switch pad, plus "Set," "Clear," "Call" and "Run." The "0" key with "Call" will indicate the number of times a program is to be repeated. As is true with many such systems, a little practice eliminates the confusion of the first attempts. "Stop" is used to return the deck to normal modes.
The "Rev Selector" slide switch, complete with little diagrams and status lights, can be set for forward, forward and reverse to stop, or for continuous cycling (play only). The deck will play or record in either direction regardless of the position of the selector. The level meters to the right are in bar-graph form with yellow for normal levels and red above zero. Adjacent to the meters are the tape-type indicators, actuated by automatic sensing of whatever cassette is inserted. This approach helps to prevent errors with tape selector switches, but the cassettes used must have the necessary sensing holes. Most present cassette shells do have the needed holes, but some off-brands and many older cassettes lack them. Lever-type switches select multiplex filter ("On/Off") and Dolby NR ("Off/B-Type/C-Type"). The dual-concentric record-level pots have good-size knobs of a design helpful to making needed adjustments.
The output-level control, on the other hand, has a short, small-diameter knob-a little difficult for stubby fingers to adjust. There are phone jacks for headphones and two microphones. A single microphone plugged into the "Left" jack provides a mono feed to both channels, a good feature.
The line in/out phono jacks are on the rear panel, as is a DIN-type socket for use with the optional RC-21 remote control. As expected, an inside look revealed a considerable amount of circuitry, with two large horizontal p.c. boards, one above the other, plus two vertical cards of fairly good size and a small one for the power supply. The parts were all identified as were the adjustment pots, etc. The soldering was generally excellent with very little flux residue. Interconnections were made with wirewrap and multi pin cables as well as some direct soldering. There were two fuses in clips noted. The transport was somewhat complicated with the two capstan and flywheel assemblies (one for each direction), the two motors, and the two solenoids used. During this check, I noted that the deck was much quieter than most while running in play.
In general, the playback responses were very good for both equalizations and both directions of play, with the great majority of points within ± 1.5 dB. The forward responses with 120 uS EQ were the exception, with high-end roll-off close to 3 dB at the highest frequencies. Play-level indications were correct on the meters, within the limits of their segment resolution. Play speed was about 0.7% fast, within acceptable limits.
The record/playback responses were surveyed with a number of tapes, including what Akai listed as the reference tapes for the deck. The best results were obtained with Maxell UD, Sony EHF and JVC ME-P, and, in general, the responses were flattest in the reverse direction. In forward, there was considerable treble boost, considered too much with the Type II and IV reference tapes. Figures 1 to 3 are the swept-frequency plots for the three tape types with Dolby C NR for both directions and without NR just for forward. In all cases, the extension of high-frequency headroom with Dolby C is quite evident. Two other generalities: The responses with Dolby C NR were flattest in reverse, and in forward the treble boost was 3 dB or more. Table I lists the-3 dB points both with and without Dolby C NR for forward mode. All of these figures are quite good, but a +3 dB limit would have produced much lower high-end limits at -20 dB record level.
The phase error between tracks and the jitter of a 10-kHz test tone was tape dependent; with Sony EHF there was no measurable phase error, and jitter was less than ± 10°. The output polarity was the same as the input in record mode, but was reversed in playback. The multiplex filter was down 3 dB at 16.1 kHz and a good 35.4 dB at 19.00 kHz. There was substantially no bias in the output during recording.
Separation between channels was 44 dB at 1 kHz, and crosstalk between adjacent tracks of opposite play direction was 75 dB down, both very good figures. Erasure of a 100-Hz tone recorded on the JVC metal tape was 58 dB, quite good.
Figure 4 shows the results of measuring the third harmonic distortion for the three tapes with Dolby C NR from 10 dB below Dolby level to the points where HDL3 = 3%. All of the curves are very linear with some slight curving at the ends.
The performance with Maxell UD was particularly good, and it was selected for tests of distortion versus frequency at 10 dB below Dolby level, with and without Dolby C NR. All of the distortion figures appearing in the plots are very good, and much better than most recorders. This is particularly true at the frequency extremes where most decks have rapidly rising distortion. Table II list the signal-to-noise ratios with both IEC A and CCIR/ARM weightings, with and without Dolby C NR, for both Dolby level and HDL3 = 3% references. All of the figures are certainly very good; they might have been even higher if the high-end frequency responses had been less elevated.
The input sensitivities were 0.2 mV for mike and 83 mV for line, which is on the high side and above the 70-mV specification. Input overload points were at a good 58 mV for mike and at something over 30 V for line. Output clipping appeared at a level equivalent to + 17.8 dB relative to meter zero. The line input impedance was 62 kilohms over a good part of the band, falling to 42 kilohms at 10 kHz and an adequate 27 kilohms at 20 kHz. The record-level pots tracked within a dB for 55 dB down from maximum, excellent performance. The line output level was 413 mV unloaded, and fell to 359 mV with a 10-kilohm load, indicative of a 1.8-kilohm source impedance. The headphone output into 8 ohms with a zero meter indication was about 2 mW and quite high in level with any of the phones tried. The output level pot sections tracked within a dB for 35 dB down from maximum, adequate for normal use.
Record-level meter responses were down 3 dB at 15.1 Hz and 28.3 kHz. The dynamic responses were close to those specified for a VU meter (300 mS) with a slightly faster attack (270 mS) and a slower decay (450 mS). The meter's peak-hold consisted of retention of the maximum level at "+ 1" or above for 1 second. The meter calibrations were very close from " 7" to "+ 1," but the readings were too high at low levels and also at "+2" and "+3." The three highest steps were a bit erratic with "+4" accurate, but "+6" requiring +7.5 dB and "+8" needing +10.1 for turn on. Each of the steps had double segments, so the resolution was less than what it appeared to be immediately. As the top-step segments varied in intensity with level, however, there was good gradation in the indication of the exact levels.
The playback speed was quite steady with time as well as with changes in line voltage. With the voltage increased to 130 V, the greatest discrepancy, just 0.1%, appeared.
There was some variation in flutter from one cassette to another: Figures of 0.05% wtd. rms and 0.08% wtd. peak were typical, including reverse mode. The wtd. rms figure is a bit above specification, but more importantly, the wtd. peak result was better than specification, indicative of very good performance. The average wind time for a C-60 cassette was 74 seconds. Run-out to stop in wind was about 3 seconds, though in play mode the switch to stop seemed immediate. Change in wind direction or going from wind to play took less than a second.
Use and Listening Tests
The wide opening of the cassette compartment door made for easy loading and unloading and gave excellent access for maintenance tasks, even better with the door cover snapped off. All of the controls and switches worked with complete reliability during the testing. The slide and level switches moved with good snap action, and the level pot design facilitated balancing channel levels, with one hand at times. The combination of logical arrangement, good labeling, and the many indicators contributed to easy use of the deck's many features. "Blank Search" and "Intro Scan" were particularly helpful at times. The metering was quite easy to use over a range of room light levels, and the one-second holds at + 1 and above helped to set levels correctly. The six-language owner's manual has many pages, a total of 72(!), but even in English alone, there are 13 pages of fairly detailed discussion. A number of very good illustrations help to make a good presentation of the various special features.
The timer start worked just fine, with a three-second delay after power turn-on. There were no record, pause or stop clicks even detected-the Akai deck is certainly one of the best in this regard. I noticed that the unit ran quite warm, which was not too surprising with all the circuitry, but it did indicate the need to keep the ventilation holes on top uncovered.
Discs used for checking record/playback performance included Mobile Fidelity releases of Kim Carnes' Mistaken Identity and Georg Solti and the London Symphony's Romantic Russia. As far as responses were concerned, there was good matching in the results with and without Dolby C NR. Comparisons between playback and the sources indicated a very slight loss in the lowest bass at times and a shift or tilt favoring the higher presence region, less so in reverse mode. There seemed to be an occasional slight hardness, but it might have gone with having record levels a bit on the high side. All in all, the Akai GX-F66RC showed very good to excellent performance in most areas with a number of very useful convenience features.
(Source: Audio magazine, Nov. 1982; Howard A. Roberson)
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