Audio Database

The

Pioneer CT-A1
230,000yen(around the 1980 time)

Description
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The stereo cassette deck which aimed at the highest class to all with 3 head schemes which adopted the Auto BLE system and the world's first ribbon sendust head.

Three head schemes which prepared sound-recording/play combination head by the world's first ribbon sendust to succeed in a development and the erase head by a special composition are adopted as a head.
The process of a ribbon sendust head makes the WIRE-center strike of a molten state blow off from a nozzle under relevant requirements, and is the rapid quenching lengthened through a direct roll. This has succeeded in 0.2mm - 0.3mm using as a 50micro thin band at once the sendust made into the limit with the conventional technology. And this ribbon sendust was molded into the lamination structure of 11 sheets, and the high region property of having improved the failure of a high region remarkably and having excelled in suppressing an occurrence of an overcurrent is realized.
Moreover, this ribbon sendust head serves as the high SN ratio and extensive dynamic-range design in which the height of permeability which the sendust itself has was employed efficiently, and also the bias efficiency ratio is also good also twice [ about ] compared with the conventional sendust head.

The reproducing head has set gap width as 0.8micro in order to reconcile the frequency characteristic in a high region, and the merit of a sensitivity, and it has succeeded in molding of a narrow gap taking advantage of the property of a ribbon sendust, without sacrificing a sensitivity.
Moreover, the recording head sets up the gap value of 2.5micro, in order to pull out the frequency characteristic at the time of a sound recording, and a sensitivity to the maximum extent, and saturation magnetic flux density is raising the quality of sound taking advantage of the merit that it is large and a sensitivity is high.

As the core spacer which right-and-left both channels adjoin fully in consideration of the shielding effect over a leakage magnetic field in a ribbon sendust head,A high nonmagnetic quantity electrical-conduction material of the electrostatic-shield effect and the shielding board by the permalloy excellent in the magnetic shield effect are adopted, and the double shielding is raising the tone quality.
Furthermore, it has a structure which gave the moderate distribution angle between both channels, and it makes the channel separation the outstanding thing by taking high-precision deep core processing technology and gap.

In the erase head, saturation magnetic flux density develops the special composition which was highly excellent in wear resistance, and is using it for a front core with the semi double gap structure. Furthermore, by composite-izing with the back core of a ferrite, the small and highly efficient erase head is realized.
Moreover, since the lamination of the front core by this special composition is carried out with 21 0.1mm light-gage sheets, there are few temperature rises by eddy current loss, and it has obtained the erasure performance as high as 76dB or more (1kHz, metal tape).

The sound-recording bias, recording level, and sound-recording equalizer which suited the tapes used by the 6-bit arithmetic processing of a microprocessor are detected automatically,The newly developed AutoBLE system (Automatic Bias SFT Level Equalizer Tuning System) set up with high precision is adopted.
In a coordination of a sound-recording bias, even when the tapes of which position is used, the sensitivity of a tapes selects the amount of bias currents whose distortion decreases highly, and sets it as an optimum value.
In a recording-level (tapes sensitivity) coordination, a recording level is changed, it controls so that Recording-play level becomes the same, and an optimum value is set up so that the curve of a code may become symmetrical by encode - also in the time of a Dolby system operation.
In a sound-recording equalizer coordination, the high region property of various tapeses is detected automatically, and it is set as an optimum value so that a sound-recording equalizer may be changed and all the bands may become a flat.
It is possible to carry the memory functionality in the AutoBLE system, to carry out memory of the coordination value of a bias level equalizer to nine kinds, and to call, when required. Furthermore, a detection of the mistake position of a tapes selector or a poor tapes is also performed, and it warns by a error display.

6-bit arithmetic processing is carried out in the AutoBLE unit which uses the microprocessor (PD-4005) in which Pioneer developed a coordination of a bias level equalizer and various kinds of controls accompanying it.
A process's push of the AutoBLE key will send a command so that it may be in a sound-recording status from an AutoBLE unit to a mechanism control circuit first. And a 1kHz oscillation signal is chosen and the signal is supplied to the recording head through sound-recording amplifier. Simultaneously, a sound-recording bias is also superimposed with a 1kHz oscillation signal through a bias variable circuitry, and is supplied to the recording head. In this way, the recorded test signal is taken out by the reproducing head, is supplied to the rectifier circuit of an AutoBLE unit, and makes a Recording-play loop.
An automatic regulation is first started from a setups of a bias. It is a scheme which this carries out variable [ of the bias current ] at 64 steps, recording a 1kHz test signal, and detects the highly precise and optimal amount of peek biases of }0.2dB out of the regeneration level,The regenerative signal given to the rectifier circuit of the AutoBLE unit was changed to DC voltage, and the microprocessor has distinguished the upper of a regeneration level by changing the voltage into digital quantity further. Since the iterative of Lch and the Rch is carried out twice, they detect this peek bias value and that average is calculated, the high robustness has been realized compared with the scheme distinguished with a one side channel and 1 time of a peek bias value.
A setups of the amount of biases will start a coordination of the optimal recording level next. Also at this time, 1Hz is used, and changing a sound-recording electric current finely at 64 steps, a test signal sets up so that it may be set to the convention level whose play Output voltage of both channel is 0dB.
At the time of a sound-recording equalizer coordination, a microprocessor chooses the test signal which is 10kHz, changes the amount of build-outs of a sound-recording equalizer at 64 steps, and makes the frequency characteristic a flat.
After all of these coordinations are completed, a tapes is automatically rewound by the operation instruction of a microprocessor till the place before a coordination start-up, and it goes into a sound-recording stand-by state.

The coordination statuses of an AutoBLE system are three light emitting diodes, and each of a sound-recording bias, a recording level, and a sound-recording equalizer is displayed. During the coordination, light emitting diode blinks and it is designed continue switching on the light after a coordination is completed.
Moreover, three light emitting diodes blink simultaneously and warn of the error display by the mistake position of a tapes selector etc.

When the backup battery for memory is built in and a plug socket is pulled out at the time of the power source off and a power-down, a storing of a microprocessor is maintained also at the time of an absence sound recording.

The Quartz PLL D.D> coreless motor is adopted as a capstan motor, and high torque called starting torque 180 g-cm is realized with the magnet (6 very) attached to the rotor, and the structure which the stator (nine coils) was made to counter superficially.
Moreover, since [ which is depended on the permanent magnet which does not use an iron core for a rotator ] a DC motor, there is no magnetic unevenness, there is no fine oscillation by the cogging or a torque ripple, and the harmful flutter component is especially decreased sharply on Hearing impression. And the rotation of a motor has adopted the direct-drive scheme which serves as a rotation of a capstan as it is, and, unlike the scheme which makes a capstan drive through a propagation organization, it has become the tapes run where the performance of the coreless motor was stabilized as it is.
Furthermore, the capstan has adopted a thick type 3mm in diameter, since the rotational frequency of a motor can be made to low-speed-ize much more also by the same direct-drive scheme, the rotation unevenness and the fine oscillation by the deflection of a motor shaft etc. are controlled, and the mechanical endurance is also raised sharply.

Quartz PLL which applies the reference signal of the highly precise crystal oscillator of }0.004% or less and of which a sample & hold is done is adopted as servo mechanism.
Moreover, the high-precision perimeter integrator type is adopted as a motor's own velocity detection organization. This generates an alternating-current signal with the magnet of 60 poles attached to the rear-view perimeter of the rotor of a capstan motor, and the low-impedance printing pattern coil of this number of poles which countered this,Low-noise-ization is also attained at the same time it waves further, it twists the precision of Quartz PLL by this by the scheme which integrates a perimeter with this further and it makes it a thing.
Furthermore, the magnetic pole change of the motor adopted the switching organization in which it did not contact according to the hall device which Pioneer developed uniquely, and has realized the quiet and smooth rotation.

The pitch control organization which can carry out variable [ of the pitch at the time of a play ] }6% is carried (it is auto cancellation at the time of a sound recording).

The driving force of the Quartz PLL D.D. capstan motor was supplied to the fly wheel for a subcapstan drive through the propagation belt, and the closed-loop dual capstan scheme which makes it run a tapes by two capstans is adopted.
The modulation noise by the tapes oscillation generated during a tapes run was intercepted out of the loop, and the high Recording play of a quality is realized.
furthermore, the thing to consider as the design which makes slow slightly the rotational frequency by the side of a subcapstan compared with the rotational frequency of a D.D. capstan, and requires a continuously uniform tape tension in a loop,It not only prevents level fluctuation and a drop-out, but it winds from the start of a volume, a head touch always good to the end is obtained, and it is raising the reliability of AutoBLE.
Furthermore, consideration which aims at a high fidelity play, such as distributing the peek component of a wow and flutter, is carried out by changing the diameter of a pinch roller on either side.

The high torque coreless motor with few torque ripples and coggings is adopted as the motor only for a reel drive, and the volume unevenness of the tapes has decreased also in the time of high-speed winding.

The ATLC organization in which the slack of a tapes is automatically removed at the time of a magnetic-tape-cassette attachment is adopted.

The newly developed advanced reel axis is adopted and the degree of splicing with the hub of a magnetic tape cassette prevents a gradual high variation of a tape tension.

The circuitry of a DC}2 power-source drive is adopted and the first rank considers play equalizer-amplifier flat amplifier as the differential-amplifier stream composition of super low-noise PNP transistor adoption,An extensive dynamic range and low-noise-ization are attained by considering the final stage of an equalizer amplifier as the push pull complimentary stream composition by PNP-NPN.

The first rank differential and the final-stage pure complimentary are adopted as sound-recording amplifier, and it has become sound-recording amplifier with a dynamic margin of 25dB (1kHz) from reference level.

Bias amplifier makes the oscillation part and the output amplifier part for a bias supplying which adopted the voltage stabilization circuitry become independent, respectively, changes the amount of biases between a bias oscillator and output amplifier, and is used as the stable circuitry which tunes finely.
Furthermore, as a complimentary output by PNP and an NPN transistor, the 3rd step of this bias supplying amplifier reduced the Output load impedance, and has realized the constant current drive of the bias in the recording head.
In this way, while applying NFB and realizing a reduction of a large distortion after improving a nakedness property, the drift property of the bias to a temperature and time is also raised greatly.

The 2 color function-logic-diagram level meter of a microprocessor application is adopted.
A level window uses 24 segments per single-sided channel, and it has become the design which covers -30dB - +8dB, and less than 0dB is carried out at blue, and 0dB or more carries out a lighting indication at an orange.
Furthermore, according to the special-NetWare-program source, this function-logic-diagram meter can switch a response characteristic to three steps, an average, a peek, and a peek hold, and can use it properly.

The electronic memory functionality in which tapes plays, such as a memory stop, a memory play, a counter repeat, and a repeat, are possible is carried.

The pure electronic formula manual operation button by control of IC logic circuitry is adopted.

A MPX filter cancel-release switchpoint, a Dolby system, the Rec mute organization, the timer standby organization, the bias fine-tune volume, the monitor switchpoint, etc. are carried.

The cassette half was held certainly and the full open loading scheme which can also perform attachment and detachment smoothly is adopted.

Mixing of a mic and a line is possible.

The output volume is carried.

Auto BLE unit Quartz PLL D.D. coreless capstan motor
The The Ribbon The
Auto BLE system automatic-adjustment process

Rating of a mode
Form Compact cassette tape deck
Head Recording head: Ribbon sendust head
Reproducing head: Ribbon sendust head
Erase head: Special composition head
Motor For a constant-speed drive: Quartz PLL direct-drive scheme coreless capstan motor
For the reeled live: High torque coreless motor
It is already volume time. 75 or less (C-60) seconds
Rotation unevenness 0.03% or less (WRMS)
Frequency characteristic
STD, LH tapes : 20Hz - 19kHz, 25Hz-16kHz}3dB (at the time of a -20dB sound recording)
Fe Cr tape : 20Hz - 20kHz, 25Hz-18kHz}3dB (at the time of a -20dB sound recording)
Chromium tapes : 20Hz - 20kHz, 25Hz-18kHz}3dB (at the time of a -20dB sound recording)
20Hz - 13kHz (at the time of a 0dB sound recording)
Metal tape : 20Hz - 20kHz, 25Hz-19kHz}3dB (at the time of a -20dB sound recording)
20Hz - 15kHz (at the time of a 0dB sound recording)
30Hz-15khz}1dB (It is about AutoBLE at the using time. At the time of a 20dB sound recording )
SN ratio (3% of 3rd THD)
Auditory sensation weighting
Dolby off: 60dB or more
Dolby on: 70dB or more (5kHz or more)
Distortion 1.0% or less (0dB)
Input sensitivity/maximum permissible input
/impedance
Line: 65mV/15V/100kohm, a pin jack
Mic: 0.3mV/100mV/10kohm, the diameter jack of 6mm
(Conformity mic impedance: 250ohms - 10kohm)
Normal-output level / maximum level
/impedance
Line: 450mV/640mV/50kohm, a pin jack
Headphone: 63mV/90 mV/8 ohm, the diameter stereo jack of 6mm
The semiconductor used IC:42
Transistor: 194
Diode: 124 (zener diode: 16, light emitting diode:19)
Phot interrupter: One
Supply voltage AC100V, 50Hz/60Hz
Power consumption 45W
Dimensions Width 420x height 217x depth of 390mm
Weight 18kg