Pioneer T-858

Commentary

A stereo cassette deck equipped with a FLAT SYSTEM for keeping the frequency characteristics of recording and reproducing flat.

The FLAT SYSTEM (Frequency-response and Level Auto Tuning System) has been developed and is equipped with the FLAT SYSTEM (Frequency-response and Level Auto Tuning System) that automatically performs calibration with high precision, maximizes the performance of the tape, and fully demonstrates the effects of the Dolby NR.
Instead of the conventional two point correction of low frequency (400 Hz) and high frequency (10 kHz), the calibration is performed by monitoring three points of low frequency (400 Hz), middle and high frequency (3 kHz), and ultra high frequency (15 kHz). Moreover, the microcomputer with the resolution of 7 bit of bias, 5 bit of level, 4 bit of middle and high frequency and 2 bit of ultra high frequency for the equalizer searches the appropriate data for the tape with high precision in a short time.
In addition, an electric volume is used for bias adjustment, and manual adjustment is possible after automatic adjustment is finished, so you can create your own favorite sound.

This is the first time that a cassette deck has been equipped with a digital tension servo for controlling reel torque with a microcomputer.
While the microcomputer controls the reel motor voltage according to the size of the winding diameter, the tape is wound at an appropriate tape tension. This improves the wow and flutter at the beginning of tape winding, which had tended to be unstable in the past.
At the time of one touch tape return, the torque is adjusted from high speed → medium speed → low speed, and the tape stops softly toward counter 0000.
In addition, the fast-forward time has been shortened, and the speed has been improved by approximately 10%.

The mechanism is equipped with the newly developed reference master mechanism NEW Z.
While inheriting the advanced basic technology of the Z Mechanism, we focused on improving the rotational accuracy of the capstan shaft, which is most closely related to the wow and flutter, in order to realize more advanced tape travel stability. To reduce the moment load due to the crimping force between the capstan shaft and the pinch roller, we extended the bearing part that supports the shaft to realize smooth rotation.
In addition, a high-rigidity, high-precision head block with a dual structure of zinc die-cast is used to suppress tape meander and microvibration. In addition, a sub-micron order capstan shaft treated with FS is used to suppress slippage between tape and capstan shaft.

The recording and reproducing heads use a laser amorphous head that uses PC-OCC (single-crystal high-purity oxygen-free copper) for coil winding.
A double-gap ferrite head with a Sendust guard is used for the erasing head.

It is equipped with a cassette stabilizer developed based on the vibration analysis of the cassette half obtained from the large general-purpose program NASTRAN developed by NASA.
The vibration level is reduced by applying damping to the part of the cassette half that is likely to cause resonance using special non-resilient rubber and a member with high rigidity.

Equipped with M / V / I mechanism to prevent high-order vibration caused by capstan motor.
In this structure, a heavy motor bracket made of special reinforced resin and an insulator made of non-resilient rubber are installed between the motor and the mechanical chassis to effectively absorb vibration energy generated by the motor in terms of both structure and material.

In order to prevent vibration caused by external sound pressure from the speakers from being transmitted to the half, the door and the cassette pocket are separated into an isorated door. The door blocks vibration and prevents sound degradation.

The deck body is equipped with a copper-plated honeycomb chassis, large honeycomb insulator, and honeycomb shield case to diffuse vibration in various directions for instantaneous attenuation, eliminating the nigori of sound.

The built-in Dolby HX PRO detects the high frequency component of the music signal, controls the bias amount to an appropriate value, and suppresses over-bias.

It is equipped with a line straight function. When a source does not require balance adjustment, it bypasses the balance volume and guides the signal to the recording amplifier through the shortest path.
By direct construction design, the power supply unit, control unit, amplifier unit, mechanical unit and FL meter unit are connected at the shortest distance respectively. In addition, the volume is placed close to the input terminal and controlled by the shaft, so that the shortest wiring distance is realized.

The power supply section is composed of four independent windings with transformer windings divided into each block such as amplifier, control and FL indication. In particular, bifilar windings made of oxygen-free copper wires are used for the amplifier transformer windings to improve the balance between + and - power supplies.

A high bias of 210 kHz is used to suppress the generation of beat and intermodulation noise due to interference between harmonics and bias current.

It is equipped with a peak level calibration function in which the microcomputer assists the accurate recording level setting.
You can easily set the appropriate level by temporarily holding the peak level of the recording source and adjusting the recording volume.
The 17-segment meter is equipped with a meter range switching function. It displays -30dB to + 12 dB in normal operation and -3dB to + 12 dB in expanded range mode in 1 dB steps, enabling severe recording adjustment.

Compatible with CD-DECK sync which can be linked with a CD player.

Equipped with a display OFF function to prevent noise from the FL display.

Equipped with a 3-mode counter that can be used as a tape counter, time counter and リメインカウンター.

Equipped with one touch Tape Return & Return Play function which rewind to counter 0000 with one touch and start playback automatically, repeat playback which repeatedly plays one side of the tape, and Auto Space REC Mute which creates a silent part for 4 seconds.

Wireless remote control is included.

Model Rating

Type	Reference 3 Head Deck
Track system	4-track, 2-channel stereo
Heads	Combination type (Laser Amorphous Recording Head / Laser Amorphous Reproducing Head) Double Gap Ferrite Erasing Head With Sendust Guard
Motor	For Capstan : DC Servo Motor For Reel : DC Motor For Assist : DC Motor
Wow and flutter	± 0.04% W · peak (EIAJ) 0.022%WRMS(JIS)
Quick Winding Time (C-60)	Approximately 75 seconds
Frequency Response (EIAJ)	Metal Tape : 15 Hz ~ 22 kHz ± 3 dB (-20dB Recording) Chrome Tape : 15 Hz ~ 20 kHz ± 3 dB (-20dB Recording) Normal tape : 15 Hz ~ 20 kHz ± 3 dB (-20dB recording)
S / N ratio (metal tape)	57 dB (EIAJ / peak recording level, acoustic correction) Dolby C on : 76 dB (3rd harmonic distortion rate 3%, audibility correction)
Distortion Factor (EIAJ/1kHz)	0.5% (metal tape, 3rd harmonic distortion factor)
Input Sensitivity / Impedance	Line : 60mV/47k Ω
Output Level / Impedance	Line : 316mV/1.8k Ω Headset : 2.3mW/8 Ω (maximum volume)
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	17W
External dimensions	Width 420x Height 135x Depth 370 mm
Weight	8.1kg
Attachment	Remote Controller CU-T012