Turn Table Unit
A unit for keeping the disc at a constant speed and maintains the base of rotation without additional noise.
A unit used to accurately trace the signal of fine sounds engraved in the disk groove at the tip of the needle.
Motor Drive Unit
A unit that continues to give accurate rotation without fluctuation to the platter that receives the disc.
A unit used to supply high quality air to make the platters and arms float.
Ultra heavy-duty design that suppresses unnecessary vibration/
Turn Table Unit
Philosophy of LFT1 anti-vibration
Analog discs are disks that record sound vibrations directly to a micron unit. Therefore, it is strictly prohibited to add vibrations other than those prerecorded into the sound groove. There are two methods of suppressing the transmission of unnecessary vibration.
These are shielding and damping. High frequency vibration can be damped by using vibration isolating materials, but low frequency vibrations cannot be isolated or shielded with materials alone. It must be suppressed by adding weight in the form of a thick concrete wall which provides both shielding and damping.
LFT 1 is committed to suppress low frequency vibration with weight and high frequency vibration with an air cushion.
Stable heavy granite base
On the base of the turntable, we use 40 kg of 500 million year old granite (granite).
Random vibrations transmitted from the floor surface will be suppressed by the weight and vibration damping characteristics of granite. Granite is used as a reference for making the mother machine (machine tool) as a stone surface plate. In addition, it is processed to the highest grade, JIS 0 ,grade flatness of 5 microns, and a distance of several microns. While keeping the floating platters are spinning.
Floating ultra-heavyweight platter
In order to obtain stable rotation, a platter with a large amount of inertial momentum is required. However, in the case of a mechanical bearing, a large force is applied to one point and causes wearing, which can lead to the generation of unnecessary vibrations and the signal of sound can be missed. LFT 1 is a platter with a high inertial momentum of 344 mm in diameter and 27 kg in weight, made of stainless steel, is rotated. The weight of the platter is handled by air pressure. By having metal bearings handle only several hundred grams of force in the lateral direction, we realized a structure that does not cause unwanted vibration and long-term reliability.
If you support the platter with one point and hit it, you will hear a metal sound, but if it floats due to air pressure it will produce a weird sound. By damping with the air film, integration with the base becomes possible, and unnecessary vibration do not follow.
Close contact record board and Heavy weight stabilizer
The place where the platter and the record board are in contact have a tapered shape and when pressed with a heavyweight stabilizer this allows close contact between the record board and the platter, suppressing unnecessary vibration when the needle point traces.
Precise rotation performance to minimize extreme fluctuation/
Motor Drive Unit MDU1
Ideology behind platter drive of LFT1
In order to pick up sound accurately from the analog disc, the rotation of the platter must be rotated at a constant speed without any "fluctuation". In general, accurate rotation is obtained by servo- control by negative feedback, but at the micro level, if it rotates or becomes faster, it detects it and slows it, and repeats the operation to make it faster if it gets slower.
Although this level and cycle are determined by the gain of the control system and the loop speed, the period of the speed control of the platter which is the mechanical system surely comes into the audio band. In general, accurate rotation is obtained by servo-control by negative feedback, but at the micro level, if it rotates or becomes faster, it detects it and slows it, and repeats the operation to make it faster if it gets slower. If you try to measure a period with a small level, you cannot measure the instantaneous state, so you should measure the average value. Therefore, fine vibration generated by servo-control cannot be measured by the measuring instrument, it depends on the human ear.
LFT1 hates this vibration and lacks convenience, but in addition to selecting an open loop control that does not apply servo-control, it also blocks out noise generated internally and externally.
In direct drive mode as well as in motor speed control mode it cannot escape the vibration caused by the servo-control. Although there is no servo-control amplifier in the synchronous motor, unnecessary vibration is minor, but the permanent magnet of the rotor constantly controls the deviation from the rotating magnetic field, and due to processing precision of the rotor, variation in magnetization and in windings vibrations are occurring.
Non-feedback motor control
In LFT 1, the rotation control is not performed, and the constant speed rotation is left to the high moment of inertia of the 27 kg platter, creating a rotation free from unnecessary vibration caused by the control. Only the positive direction force is applied from the motor, but by using a coreless motor with less moment of inertia, the influence of the vibration is reduced. Motor rotation control with no negative feedback · The XFD method realizes a drive with the minimum fluctuation.
*XFD method: Based on a crystal oscillator with high frequency precision, a direct digital voltage generator is formed to supply a voltage with high precision without fluctuation. It is a system that was independently developed by CS Port. It is a system that eliminates fluctuation by driving a super heavy platter with light load bearing with a low inertia coreless DC motor.
Adoption of thread drive
There are various methods such as gear drive, rim drive, belt drive, etc. to transmit the power of the motor to the platter, but LFT 1 adopted Kevlar's four braid wire that is stronger than iron. The disadvantage of this is that it takes time to start up. However, motor vibration is minimal, elongation is minor, and it allows the platter to run firmly.
Setting and checking rotational speed by strobe
A strobe set to 33 1/3 and 45 revolutions with a crystal transmitter as a reference places marks engraved with high precision with a laser on one side of the platters.
Rotation speed is adjusted with the + and - speed setting buttons, and the rotation accuracy can be judged by the strobe mark.
Stable arm unit supports fine needle tip/
Arm Unit AFU1
LFT1 sound pickup philosophy
In the LP record, sound grooves of 120 micron width are engraved at intervals of 600 or more from the outer circumference to the inner circumference, and the needle traces submicron music signals.
Characteristics of the arm are, no fine movement when the cartridge traces the signal, moves lightly to the adjacent sound groove moves, does not receive unnecessary vibration from the surroundings, vibration generated by the needle is generated only in the generating coil. In the production process of analog discs, since the movement of the cutting race becomes a straight line, linear movement is also required for the head. In LFT1, linear tracking was realized by floatation, the fine movement at the time of signal tracing was suppressed by the weight of the arm, and the movement to the adjacent groove slowly moved lightly. Vibration generated at the tip of the needle is transmitted through the arm and damped by the air layer of the slider part, so it will not be reflected to the tip of the needle.
Linear tracking arm
Record grooves are not engraved at regular intervals, and where the signal is small, the interval is small, whereas where the signal is large the interval is large, earning the time to be able to reproduce.
In the past, several linear tracking arms that detected the angle of the needle tip and served a serial control were suggested, but since there was a disadvantage of the servo-control, as described above, it disappeared from the market.
In LFT 1, the arm can be moved with a force of 0.5 g or less by its own floating structure, and the irregular record groove is stably traced from the outer periphery to the inner periphery. Also, heavyweight arm units are not swayed by music signals, they trace without missing the fine movements of the needlepoints.
Unnecessary vibration generated at the needle tip
Mechanical vibration traced by the needle point is converted into electric signal by the generating coil, but this mechanical vibration passes through the stylus, cartridge body, shell and arm, it is reflected at the mechanical contact point and returns to the tip of the needle, adds extra things to the playback signal. LFTl dumps the vibration from the tip of the needle at the levitating part of the slider, as well as the damping effect of unnecessary vibration from the outside, it becomes a performance like a silent forest.
Pump Unit POU1/
Air pulse technology even trusted in the medical field.
The LFT1 comes with an air pump unit for levitating platters and arms. The air pump is driven by 12 VDC supplied from the motor drive unit, and by adopting a motor type pump used in medical equipment etc., it gives stable operation for a long time.
Because the compressed air coming out of the pump is a pulsating, it can be supplied as compressed air with no ripple and vibration by Π type filter.
Furthermore, it adopts a sound leakage prevention system with a double sealed structure. This maintains a low volume even if installed in a listening room.
Analog disk player LFT1
Turntable / motor drive unit
|Base||JIS 0 class granite surface plate base|
|Platter||Air float 27 kg High inertia stainless steel platter|
|Drive system||Quartz-follow No feedback motor drive XFD method|
|Rotation transmission method||Yarn drive (four-fiber aramid)|
|Drive motor||DC coreless low noise motor|
|Rotation speed||33 1/3 and 45 rpm Switch switching With rotation fine adjustment|
|Wow and flutter||Wow 0.2% , Flutter 0.04% less|
|Power supply||AC100/120/200/240V 50,60Hz|
|Method||Air float type linear tracking arm|
|Arm lifting mechanism||Manual operation with lever|
|Azimuth / arm length adjustment||Adjustment with fixing screw|
|Compliant cartridge weight||20g-40g （Including shell）|
|Compatible stylus pressure||1.5-5g|
|Adjustment of needle pressure||Static balance|
|Output terminal||DIN 5P|
Air pump section
|Air volume||Supplied to platter and arm|
|Power supply||DC12V Supplied from motor drive unit|
Weight / Size
|Accessories||AC power cable, DC cable, DIN 5P phono cable, cartridge shell, arm setting gauge, level, air tube, two drive yarns (player board is optional)|
|Warranty period||5 years (excluding consumables) registration is required|