Technics SL-P720
¥ 79,800 (around 1987)
Commentary
This is a full-featured CD player that inherits the SL-P1200 technology and incorporates classAA and other technologies.
ClassAA audio circuits are used for the sample-and-hold circuit and buffer amplifier.
In the sample-and-hold circuit, the voltage-controlled amplifier is released from the capacitive heavy load drive in which the holding capacitor is charged with the sampling signal of D/A, and the information on the CD is transmitted to the subsequent stage without losing the amount of information.
In addition, the buffer amplifier realizes stable waveform transmission regardless of complicated loads such as the input impedance of the connected preamplifier and the capacitive load of the connecting cable.
ClassAA is also used for the I/V converter of the D/A converter outputs to realize high-speed and high-precision L/R and I/V conversion.
A newly developed 96th order digital filter and 5th order analog low-pass filter are combined into a super-clean digital filter for the audio circuit.
By eliminating unnecessary noise components, phase characteristics, distortion characteristics and frequency characteristics have been improved.
As for the parts that make up the audio circuit, we have studied both physical characteristics and listening tests to obtain high-quality sound.
We use a large amount of copper and polystyrene capacitors and fine ceramic electrolytic capacitors for audio equipment.
We also conduct strict sound quality checks on low-pass filters, including printed wiring materials on ceramic substrates.
To prevent noise from the digital circuit and servo circuit to the audio circuit, the power supply for the audio circuit is configured independently of the digital circuit and servo circuit to prevent interference between the circuits.
A unique single-beam FF-1 laser pick-up is used for the pick-up part that reads signals from the disk.
Compared with the conventional 3-beam system, the laser light utilization efficiency is higher and the SN ratio of the reproduced signal is improved.
Combined with the use of digital accu-servo systems and CCF lens systems, we have also obtained excellent signal reading capabilities that are resistant to disc scratches and fingerprints.
In order to suppress the vibration which adversely affects the sound quality of the CD player, a thorough vibration countermeasure is taken.
First of all, we have adopted a two layer composite weight base consisting of a metal chassis and TNRC for sound pressure vibration from speakers. This product was developed after repeated studies of material, shape, and bolt position through vibration analysis by laser holography. It has sufficient weight and strength as well as high damping effect.
In addition, a special anti-vibration material determined by computer simulation is used for the upper part of the cabinet to enhance anti-vibration.
In addition, to prevent floor vibration transmitted to the installation platform, four large insulators block vibration transmitted to the player body, and the optical deck is made into a double insulator structure in which the loading mechanism and the optical deck float from the body to shut out floor vibration.
In addition, the power transformer is also floated with special damping rubber to ensure complete vibration-free and resonance-free design.
Equipped with a 2-speed search dial that enables fine head detection in both forward and reverse directions.
The playback speed per rotation is approximately 1 second (slow) 1 second (slow) and approximately 30 seconds (fast).
If you set it to the slow side, you can access precisely in units of three frames (1/25 second) at the minimum.
By adopting a traverse feed mechanism using linear motor controlled by microcomputer, high-speed heading of average 0.9 seconds is realized.
Quietness and durability have also been improved.
It is equipped with a programmable music scan function that plays only the intro part of a song sequentially.
The playing time can be set freely from 1 to 99 seconds.
It can be operated at hand with the attached 10-key remote control.
It also has a digital attenuator function that can adjust the volume from 0 dB to -12dB in 2 dB increments.
Model Rating
| Type | CD Player |
| <Audio section> | |
| Output voltage | 2.0 v (0 dB, EIAJ) |
| Frequency characteristic | 4 Hz to 20000 Hz ± 0.2 dB (EIAJ) |
| Dynamic range | 96 dB or more (EIAJ) |
| Signal-to-noise ratio | 101 dB or more (EIAJ) |
| Total harmonic distortion factor | 0.003% or Less (1 kHz, 0 dB, EIAJ) |
| Harmonic distortion factor | 0.0015% or Less (1 kHz, 0 dB) |
| Channel separation | 105 dB or more |
| Wow flutter | Below Measurement Limit (EIAJ) |
| Signal Format | |
| Sampling frequency | 44.1kHz |
| Error correction system | Technics super decoding algorithm |
| Compound | 16-bit straight line |
| <Pickup> | |
| Method | FF-1 |
| Light source | Semiconductor laser |
| Wave length | 780nm |
| <Traverse> | |
| Method | High-speed linear access system |
| <Spindle> | |
| Method | Brushless D. D. |
| <General> | |
| Headphone output level | Max. 15mW/32 Ω (variable) |
| Power consumption | 9W |
| Pwer | 100 VAC, 50/60Hz |
| External dimensions | Width 430x Height 97.5x Depth 260 mm |
| Weight | 5.2kg |
| Included : Wireless Remote Control | |
| Feature | 27 key |
| Dry batteries | AA Dry Battery 1.5Vx2 |
| External dimensions | Width 65x Depth 155x Thickness 18 mm |
| Weight | 140g (including dry batteries) |