SONY TC-6150SD
¥ 128,000 (around 1973)
¥ 156,000 (around 1979)
Commentary
This is a high-end 3-head cassette deck with a closed-loop dual capstan system. It is not simply a 3-head cassette deck. It consists of a recording and playback head and an amplifier. It also uses a closed-loop dual capstan system.
The tape transport mechanism uses a closed-loop dual capstan system.
Two sets of capstan and pinch rollers are used, and the recording head and reproducing head are placed in the center of the capstan. Therefore, vibration, tension and unevenness transmitted from the reel shaft and cassette half are suppressed in front of the head, and wow flutter is improved and modulation noise is prevented.
This method takes advantage of the slight difference in rotation between the two capstans to obtain the tape tension, so the head touch is good and the level fluctuation is suppressed.
As a 3-head system, the accuracy of the tape guiding is further improved, and in order to eliminate the phase difference in the tape guiding during recording and playback, we first pursue accuracy that is said to be impossible.
In order to reduce the hissing of the tape, a Dolby system is installed.
The recording volume is automatically increased to match the level and frequency, and the sound is attenuated and restored when it is played. This reduces the noise component regardless of the sound quality.
The 3-head system has four built-in Dolby noise reduction circuits for recording and playback, enabling simultaneous Dolby recording and Dolby playback.
The F & F (Ferrite & Ferrite) head developed by Sony's proprietary processing technology is used for the head. Based on the results of analysis based on accumulated technologies, the gap of the recording head is set to a 7 μ wide gap and the gap of the reproducing head is set to a 0.9 μ ultranarrow gap.
This head has an all-ferrite structure in which both the core and guard sections are ferrite. In addition, the gap spacer and core sections are fixed by fusing and welding ferrite and strain-free glass with the same hardness developed by Sony's proprietary technology.
As a result, the abrasion resistance is approximately 200 times higher than that of the conventional laminated head, and the bias value set in the initial stage is almost perfectly guaranteed without causing the head to decrease in one side, collapse of the gap edge, or displacement.
In addition, by making full use of the extremely high gap forming technology, the position accuracy (in-line property) of the gap is excellent, and there is no angle loss or phase shift of L/R in principle. In addition, since the front surface of the head is finished with a uniform black mirror (mirror surface), the head touch of the tape is good and dust adhesion is less.
It uses a peak level indicator using Sony's newly developed light-emitting diodes and a large VU meter that is independent on the left and right sides, making it possible to read an accurate decibel scale.
A FET is used for the first stage of the head amplifier and an IC amplifier is combined with the FET to improve distortion and linearity. In addition, a direct coupling method is adopted in which an F & F head is directly connected to the FET. There is no element between the head and the first stage FET, so S/N and frequency characteristics are greatly improved.
In order to bring out the characteristics of various tapes, a 3-position tape selector is installed for each bias and equalizer.
Equipped with Dolby Calibration to ensure correct Dolby levels, it can handle any tape with different tape sensitivities and eliminate mismatches due to sensitivity variations.
The adjustment includes a built-in 400 Hz oscillator, so adjust the recording level adjustment knob so that the pointer of the large VU meter points to 0 VU.
In addition to Dolby NR, it can also be used as a recording sensitivity calibration.
In order to prevent the 19 kHz pilot signal from the MPX circuit of the FM tuner from being erroneously recorded, it is equipped with a high-cut filter that cuts frequencies above 19 kHz.
Equipped with a long stroke slide volume that enables line / microphone mixing.
The Sony Limiter method is installed to prevent distortion caused by unexpected large input during recording.
If the limiter switch is turned ON after manual level adjustment, the correct input will be recorded as manual recording, and the limiter circuit will operate automatically only when a large input is suddenly input, preventing distortion.
Manual recording is also possible by turning off the switch.
Whether recording, playing, fast-forwarding or rewinding, it is equipped with an auto shut-off mechanism that automatically releases the operation button, head and pinch roller when the tape is finished winding and returns to the stop position, preventing unnecessary burden on the mechanism and the tape.
Since detection is performed by an electronic circuit using a Hall IC, response speed and synchronized operation with the memory counter are improved.
It is equipped with a tape counter with an accurate 3-digit memory.
Equipped with a headphone level selection switch, the volume can be changed in two stages : -30dBs at level 1 and -22dBs at level 2.
Equipped with line-out volume, playback output can be variable.
Equipped with Dolby, Limiter, Recording, Display lamp which shows pose and action state at a glance.
It is equipped with an FM absence recording mechanism. If you set a timer at a specified time in advance, it automatically operates at that time.
During rest, the pinch roller is released and does not burden the mechanism.
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Model Rating
| Type | 3-head cassette tape deck | ||||
| Tape speed | 4.8cm/s | ||||
| Available recording time | 120 minutes round trip by C-120 | ||||
| Fast-forward and rewind time | 1 min 20 sec (at C-60) | ||||
| Track system | 4-track 2-channel stereo | ||||
| Recording bias frequency | 105kHz | ||||
| Signal-to-noise ratio | General Tape : 53 dB Duadferi Chrome Tape : 55 dB Dolby on : 1 kHz 5 dB, 5 kHz or more 10 dB improvement |
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| Overall strain rate | 2% | ||||
| Frequency characteristic | General Tape : 20 Hz ~ 17 kHz Duadferi Chrome Tape : 20 Hz to 20 kHz |
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| Wow and flutter | 0.08%WRMS | ||||
| Input jack |
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| Output jack |
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| Recording and reconnector | Input impedance : 10k Ω or less Output impedance : 10k Ω or less |
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| Semiconductor used | Transistor : 53 FET : 2 IC : 11 Hall IC : 1 unit Diode : 45 pcs Light emitting diode : 1 |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||
| Power consumption | 32W | ||||
| External dimensions | Width 435x Height 155x Depth 325 mm | ||||
| Weight | 10kg | ||||
| Attachment | Connection code RK-74x2 pieces Head Cleaning Rod x1 Set |