Technics RS-B905

Commentary

A 3-head cassette deck equipped with a 3 nr system.

Closed loop dual capstan system is adopted for the mechanism part.
This system consists of two sets of capstan and pinch rollers with the head at the center. By applying a certain tension to the tape around the head, good head touch is obtained, and disturbance generated between the half and the tape is cut. This enables stable tape travel and greatly reduces modulation noise.

It uses Technics's original precision die-casting integrated structure mechanical base. Two sets of capstan, pinch roller, head block and half guide pin are integrated by precision die-casting. This increases the relative positioning accuracy of individual parts.
In addition, the relative position of each part is determined one by one through computer-aided design, measurement, and examination. Combined with the large inertia mass of the brass scraping flywheel, the closed-loop accuracy is further improved.

The head part uses a high-precision, pivot, balanced head block system.
In this system, the read / write combination head and erase head are incorporated into a precision die-cast base to eliminate the influence of vibration and secular change. In addition, the needle pivot clarifies the reference position of the head and realizes precise positioning of the tape touch. This improves the adjustment accuracy of azimuth, etc.
It also employs a three head system that uses an efficient wide-gap (4 μ) recording head and a high-frequency (1 μ) reproducing head.

The Dolby HX-PRO system is installed to improve the recording quality of high-frequency sources such as CDs.
The Dolby HX-PRO detects the high-frequency component of a music source that constantly changes, and controls the bias current according to the change to set the optimum bias value for each moment. This prevents over-bias for the high-frequency range and provides a bias amount equivalent to the ideal setting value for the low-frequency range. This greatly improves the high-frequency range without deteriorating the low-frequency range. This is an excellent effect.
Unlike a noise reduction system, tapes recorded with the Dolby HX-PRO are compatible with all decks, so you can get better sound quality when playing back.

As a noise reduction system, it is equipped with 3 nr of Dolby B and C in addition to the dbx system.

A complex load is connected to the output of the recording equalizer amplifier that supplies recording current to the head, causing current and voltage and voltage phases and causes distortion. To solve this problem, the RS-B905 uses Technics's unique classAA.
The classAA circuit consists of a voltage-controlled amplifier and a current-driven amplifier. Since the voltage-controlled amplifier, which is not affected by the load at all, is selected for the waveform, excellent response waveform and low distortion factor are achieved.

In the amplifier section of a cassette deck, the phase-frequency characteristics in the high-frequency range change in a complicated manner, causing a shift, which in particular affects the music signal during dubbing, resulting in poor sound quality.
The RS-B905 has a built-in phase correction circuit to eliminate the phase shift in the high-frequency range, and by keeping the group delay characteristic of the music signal constant, recording and playback faithful to the input signal are realized.

Equipped with a REC calibration function that flattens the frequency response by correcting the difference in sensitivity of the tape.

It is equipped with a 10 khz ± 4 db bias adjustment mechanism.

Equipped with a wide range 3-color FL peak meter of -40dB to + 18 db that covers the dynamic range of dbx.
It also has an electronic counter that displays the amount of tape travel.

Equipped with a 16 repeat performance function that allows one side of the tape to be listened repeatedly.

Equipped with an auto REC mute function, you can automatically create an approximately 4-second unrecorded portion when recording.

Equipped with a music selector.

Equipped with timer rec & play function.

Equipped with an auto tape selector.

Equipped with an independent headphone volume.

Model Rating

Type	3-head cassette deck
Heads	Recording / Playback : R/P Combination MX Head Erasing : double-gap ferrite
Wow flutter	0.04%(W.R.M.S.) ± 0.08% (W. Peak, EIAJ)
Frequency characteristic	Normal (ED) : 20 Hz to 20 kHz, 30 Hz to 18 kHz ± 3 dB (EIAJ) CrO2(EX) : 20 Hz to 21 kHz, 30 Hz to 19 kHz ± 3 dB (EIAJ) Metal (EM) : 20 Hz to 22 kHz, 30 Hz to 20 kHz ± 3 dB (EIAJ)
Signal-to-noise ratio	NR off : 60 dB (Chrome Tape, W. T. D., 1 kHz, 3% Third Order Distortion) 56 dB (Chrome Tape, EIAJ) Dolby B NR in : 66 dB (EX Tape, W. T. D., 1 kHz, 3% third order distortion) Dolby C NR in : 72 dB (EX Tape, W. T. D., 1 kHz, 3% third order distortion) Dbx in : 92 dB (Chrome Tape, W. T. D., 1 kHz, 3% Third Order Distortion)
Input terminal	Line : 60mV/47k Ω
Output terminal	Line : 400mV/2.2k Ω Headphone : 125mV/8 Ω (Compatible Impedance 8 Ω ~ 600 Ω)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	25W
External dimensions	Width 430x Height 109.5x Depth 285 mm
Weight	5kg