What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Mitsubishi LT-5V turntable

Vertical Format Linear Tracking Fully Automatic LSI Logic Turntable Unit

1 - Linear Tracking - A Major Advance in Turntable Performance
Many disc audition problems arise because conventional tone arms swing in an arc across the disc from a single pivot. This innovative unit features linear tracking with the stylus and tone arm traveling in a straight line across the disc, foiiowing precisely the same path as the head of the cutting machine that made the disc. The improvement in performance is clearly audible, and marks a moajor step forward in turntable unit design.

2 - The Linear Tracking Mechanism
To keep the cartridge stylus always precisely at right angles to the disc groove, two sensitive optical sensors detect the slightest deviation from the proper tracking position. The unbalanced signal from the two sensors actuates a servomotor that immediately moves the tone-arm base the correct distance in towards the center of the disc. Therefore, as the groove spirals inwards, the tonearm assembly moves across with it. This system is so sensitive that it can respond accurately to the differences in the pitch at which the groove was cut  (loud passages are cut at a larger pitch). The high precision servo-motor drives the tone-arm assembly via a specially wound stainless steel wire, wire tension is kept constant by spring loading and the servomotor rotation is applied by a worm type reduction gear. This system holds the tone-arm assembly firmly in position unlike linear motors where the assembly is free to slip and slide. The entire tone-arm assembly rides on a mirror finished high precision rod of nonmagnetic stainless steel, providing stability and rigidity.

3 - Low Tracking Error Means Superb Trackability
Conventional tone arms have tracking errors of several degrees. The LT-5V tracking error is never greater than ±0,1°, a dramatic improvement in the ability of the stylus to trace the groove accurately. The result is a reduction in distortion that shows itself in better definition of the stereo sound field and a more realistic recreation of the original atmosphere of the performance, with each instrument clearly located. All cartridges will benefit from this improvement the better the cartridge, the greater the advantage.

4 - A Short, Straight Arm with Fewer resonances
Conventional arms suffer two important disadvantages. In order to reduce tracking error, they have to be made as long as possible, and they have to set the cartridge off at an angle to the pipe (usually by putting an "S" or "J" bend in the pipe). Increased length means greater effective mass or, if a lighweight material is used in an effort to reduce mass, the tone arm has a stronger tendency to resonate. The short, straight arm of the LT-5V achieves greater strength and reduced resonances using a structure of stainless steel, giving a sound that preserves the full impact of transients and excellent definition right down into the deep bass region.

5 - Improved Stereo Channel Balance
Since the stylus is always at right angles to the groove, there are effectively no unbalanced forces on the stylus. Not only does this remove the need for inside-force cancellers. It also preserves channel balance and separation, ensuring much more faithful reproduction.

6 - Vertical Configuration Improves Feedback Margins
Vibration from speaker systems can sometimes cause acoustic feedback to the stylus tip and serious loss of high-level listening quality even when it doesn't result in a continuous "howl' that prevents normal listening. The vertical turntable configuration is much less sensitive to feedback than horizontal units because the vibration from the speaker systems is at right angles to the motion of the stylus in tracking the groove.

7 - Simple,Accurate Dial-Setting of Stylus Tracking Force
The tone arm hangs vertically down, statically balanced in all three dimensions for completely stable and accurate tracking of the groove. It is therefore able to follow even warped discs - and cope with vibrations - with much less tebdency to skip out of the groove.
The vertical format has another important advantage; since the weight of the cartridge itself acts at right angles to teh tracking forcee. It has no effect on it. So once the right tracking force has been set, there is no need to re-balance and reset it when swap ping cartridges. And the simple dial-setting adjustment of tracking force could hardly be easier to use.

8 - Record Clamp and Stabilizer
A spring loaded clamp secures the disc to the vertical turntable. Hinging completely out of the way for convenience, it snaps into position positively, and applies a slight pressure that brings the disc into contact with the dished turntable mat. It thus acts as a disc stabilizer, reducing vibration and improving the crispness of bass response. The upper edge of the clamp has a scale that corresponds with the scale above the tone-arm assembly. Use these two scales to locate any track you want to play,, and to guide the stylus precisely to the lead-in groove.

9 - Double Flywheel Drive System
In addition to the flywheel effect of the turntable itself there is a second counterweight flywheel. Together, they are accurately dynamically balanced for smooth and stable rotation, with high precision bearings.

10 - Fully Electronic Auto Control
The brain of the comprehensive automatic functions is an LSI computer on a chip specially developed by Mitsubishi Electric. It takes the signals from the push-button controls and from the photoelectric sensors that detect the presence and size of the disc on the turntable, and guides the stylus unerringly to the lead-in groove, automatically choosing 45 rpm for 7" and 33 rpm for 12" discs. It also enables a number of other useful and unusual automatic functions.

11 - Optical Display
LED indicators show the movement of the tone arm in real time, whether to left or right and up and down - they cease to indicate once the stylus is on the surface of the disc. The LED tracking error indicator gives a quick and positive indication of serious tracking errors. It is also useful in checking that the arm is hanging perfectly vertical.

Specifications
Drive:  Phase-locked loop belt drive by DC servomotor
Platter Diameter:  304 mm 912") diecast Al.
Olatter Weight:  1,3 kg (2lb 14 oz)
Moment of Inertia:  300 g/cm/s²
Speeds:  33 and 45 rpm adjust. ±3%
Speed Selection:  Auto/manual
Wow and Flutter:  0,045% WRMS
Signal-to-Noise ratio: 65 dB (IEC-B);  76 dB (DIN B)
Tonearm Type:  Straight universal, static balanced
Overall length:  223 mm (8-3/4")
Effective lebgth:  180 mm (7-1/8")
Tracking Error:  ±0,1°
Headshell:  GFRP (6,2 g)
Cartridge Weights:  10 - 20 g
Power Consumption:  14 W
Dimensions (W x H x D):  466 x 430 x 200 mm (18-3/8" x 17" x 7-7/8")
Weight:  12,5 kg (27 lb 8 oz)

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