SONY TC-2250SD

Commentary

A stereo cassette deck equipped with a Dolby system.

In order to produce products that comply with the Dolby Standard, for example, the inspection system requires twice as many personnel and equipment as the conventional system. Thus, we have established a high-quality production system.

F & F (ferrite & ferrite) head is adopted for the head.
This head is 200 times more wear-resistant than conventional laminated heads, and does not cause unbalanced wear of the head, so it does not adversely affect the frequency characteristics.
In addition to the core part, uniform ferrite is adopted to the guard part, and it is fused and welded with unstrained glass with extremely high hardness. This prevents not only changes due to temperature and humidity but also collapse and disturbance of the gap edge due to aging.
In addition, the black mirror finish solves the problem of dust adhesion.

A stabilization circuit is built in to prevent the precise characteristics of Dolby from being not obtained due to the bias caused by the change of the power supply voltage. The head and the first stage FET of the head amplifier are directly connected to improve the frequency characteristics and S/N in the low frequency range.

The Dolby Noise Reduction System compresses the noise-sensitive area and records it, then expands the compressed area by the same amount during playback.
This reduces the audible noise.

The preamplifier section uses two low-noise FETs with excellent linearity and high-frequency characteristics at the first stage.
In addition, the silicon transistor used is of low noise and high gain type.

The mechanism uses a closed-loop dual capstan system in which the head is placed in the center of two capstan.
As a result, not only a constant head touch can be obtained, but also vibration and uneven tension caused by the moving of the tape can be suppressed, improving the running stability of the tape.
In addition, a hysteresis synchronous motor with anti-vibration measures is adopted to improve wow flutter.

It is equipped with a tape selector and a Sony Chromicassette (CrO₂It is possible to record and play back the sound drawing out the performance of.

SQ4 channels can be recorded and played back.

It is equipped with Sony's original limiter recording method. If the limiter switch is turned ON after manual level adjustment, manual recording is performed when an appropriate input is entered. The limiter circuit operates automatically only when a large input is entered to prevent distortion.
Manual recording is also possible by turning off the switch.

In order to ensure accurate synchronized operation with the memory counter, an auto shut-off mechanism with built-in electronic circuit is adopted. When the tape has been wound, the operation button and the head pinch roller automatically return to the stop position and the mechanism is released regardless of recording, playback, fast forward or rewind.
This prevents unnecessary stress on the mechanism and tape.

Uses a memory counter.

It has a built-in see-through lamp that is easy to understand the tape condition.

The lid of the eject box is designed to be easily removed so that the head can be easily cleaned.

Model Rating

Type	Dolby built-in cassette deck
Tape speed	4.8cm/s
Track system	4-track 2-channel stereo
Recording time	120 minutes round trip by C-120
Fast-forward and rewind time	1 min 30 sec (at C-60)
Recording bias frequency	85kHz
Total S/N	49 dB (Dolby In : 1 kHz 5 dB, 5 kHz 10 dB improvement)
Overall strain rate	2%
Frequency characteristic	20 Hz ~ 17 kHz (when Sony Chromicassette is used) 20 Hz ~ 15 kHz (When Using General Tape)
Wow and flutter	0.1%Wrms
Input Sensitivity / Impedance	My Kujac (2 systems) : maximum sensitivity 0.2 mV / low impedance Line input jack (2 systems) : maximum sensitivity 0.06V/100k Ω Re-connector (input side) : 2.2k Ω
Output Level / Impedance	Line output jack (2 systems) : Reference output 0.775V/10k Ω or more Stereo headphone jack : 8 Ω Re-connector : 8.2k Ω
Semiconductor used	Transistor : 42 FET : 2 Diode : 27 units SMD : 1
Pwer	100 VAC, 50Hz/60Hz
Power consumption	18W
External dimensions	Width 400x Height 127x Depth 276 mm
Weight	6.6kg
Attachment	Connection code RK-74x2 Head Cleaning Rod x1 Set