DENON DR-M9

Commentary

This is a cassette deck 3rd generation model of the M series.

The mechanism uses a two capstan system. In this system, two sets of capstan and pinch rollers are installed around the head. By changing the diameter of each flywheel, the two capstan's rotation speed is slightly different. This generates an appropriate amount of tape tension near the head to obtain good head touch. In addition, disturbance such as tape vibration caused by hub-swelling in the cassette half and sliding of the tape with the slip sheet is cut off before it affects the head surface, and clear sound quality with less modulation noise is obtained.
In addition, a special treatment is applied to the capstan on the take-up side to increase the friction coefficient.

The capstan motor uses a direct-drive motor. This motor uses a unique flat-faced design to obtain strong rotational torque and eliminate uneven torque. In addition, the brushless structure eliminates electrical noise and improves durability.
In addition, the capstan is directly driven and directly servoed in combination with a velocity detection mechanism attached to the fly-wheel surface to improve wow flutter. The servo circuit uses an all-round integrated sample-and-hold FG servo, which provides high gain and stability.

The reel motor uses a low-cocking 5-pole motor that is also used in VCRs.
In addition, by adopting a non-slip reel drive mechanism that takes advantage of the relationship characteristics between the rotational speed and torque of the reel motor, uniform winding tension is always achieved. In addition, stable tape winding is achieved by eliminating the slip mechanism that changes subtly with temperature and time.

A silent mechanism is adopted to eliminate mechanical noise.
This system uses a motor system exclusively for mechanical control. It does not have a plunger, etc. and does not have a complicated power transmission mechanism such as a gear lever, so it realizes a noiseless, highly reliable and simple mechanism.
In addition, a computer control system has been introduced to eliminate tape overruns due to time lag, which is a problem in motor cam drive. A computer is installed between an optical detection counter and a unique position detection encoder and the mechanical drive motor, and accurate control is achieved by searching for tape points and checking drive mode.
In this silent mechanism, although it is controlled by a motor mechanism, the mechanism returns to the stop position when it is stopped, such as when recording the absence, so there is no deformation of the pinch roller or tape.
In addition, the DR-M9 and DR-M8 have newly adopted a low-vibration motor as a motor exclusively for mechanical control, further reducing noise.

Uses SF (Super Frequency) combination head for recording and reproducing head.
The SF head uses a super-permalloy core with a high saturation magnetic flux density in the recording head to enhance abrasion resistance and maximize the MOL of various tapes. The reproducing head uses a high-density ferrite core with low high-frequency loss and excellent abrasion resistance. Moreover, by reducing the amount of magnetic particles to less than 1/2 of conventional magnetic particles, fluctuations in magnetic characteristics due to sliding noise and temperature changes are improved.
In addition, the recording / re-azimuth offset is reduced by limiting the parallel offset between the recording gap and the playback gap to 1/20 degree or less. In addition, oxygen-free copper wire is used for the coil to obtain wide frequency characteristics.

The power supply circuit completely separates the amplifier system from the logic system to eliminate mutual interference.

The recording -noise differential input push-pull DC amplifier circuit is used for the recording and playback amplifiers. A ± 2 power supply system is used to supply a high-voltage power supply. This increases the dynamic range and prevents clipping distortion in the signal transmission system. Furthermore, the capacitor between the playback head and the first stage amplifier is removed, and the last stage is composed of a DC amplifier.
High-stability newly developed transformer and push-pull configuration are adopted for the bias circuit, and erase noise is reduced by improving bias waveform distortion.

Equipped with a computer tuning function that can be tuned to each tape.
This function allows the computer to automatically set the best position for the tape and set the frequency response to flat.

Equipped with Dolby B Type and Dolby C Type as noise reduction system.
These circuits are double double-Dolby configuration so that Dolby playback is possible even during after (simultaneous) monitoring.

Equipped with an MPX filter switch, it can prevent Dolby malfunction by cutting the 19 khz pilot signal included in FM radio wave.

In addition to the tape counter and level meter, it also uses a centralized display that integrates various displays.
This display automatically displays the tape position, gives an indication of the recording level at that position on a bar graph, and also uses peak hold which is Oatley set every 1.5 seconds.

Equipped with output level control that can also be used to adjust the volume of headphones.

Equipped with timer play / rec mechanism. By connecting a timer sold separately, it is possible to record your absence and play an alarm.

Equipped with a one touch rec-pause mechanism, recording stand-by state can be set just by pressing the Rec button.

The Pause/Mute mechanism is used to combine the Rec Mute and Pause to improve operability.
When recording, press and hold this switch to Rec Mute, release it to Pause, and press the Play switch again to return to recording.

Equipped with a follow-up recording mechanism, you can change from a regenerating condition with the tape running to a recording state with one touch operation.

Equipped with remote control terminal and separately sold remote control unit RC-57 can be used.

Model Rating

Type	Cassette deck
Track system	4-track 2-channel stereo
Tape selector	3-Level Auto Tape Selector (Normal, CrO2, Metal)
Heads	Recording : SF Combination Head Erasing : double-gap ferrite heads
Motor	For Capstan : FG Servo DD Motor For Reel : 5 Pole DC Motor For mechanical control : low-vibration DC motor
Wow and flutter	± 0.04% (W. Peak) 0.027%(WRMS)
Early winding time	Approximately 90 seconds (C-60)
Overall frequency response (input -20VU)	Metal tape : 20 Hz to 22 kHz (25 Hz to 20 kHz ± 3 dB)
Overall signal-to-noise ratio	73 dB or more (CCIR/ARM measurement method for 3% THD level)
Input terminal	Line : 77.5mV/50k Ω Unbalanced
Output Terminal (Vol. max)	Line : at 775mV/10k Ω load Headphone : 1.2mW/8 Ω load (suitable for 8 Ω ~ 1.2k Ω headphones)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	22W
External dimensions	Width 434x Height 115x Depth 286 mm
Weight	5.8kg
Sold separately : Remote Control Unit RC-57 (¥ 6,000)
Cord length	5m
External dimensions	38 mm wide x 17 mm high x 120 mm deep
Weight	Approx. 160g (including cord)