KENWOOD(켄우드) L-07D 턴테이블

[판돌이]

넘사벽의 스팩을 자랑하는 KENWOOD(켄우드)의 플래그쉽 모델인  L-07D 턴테이블 입니다.
 
출시가격은
 
초기형 ¥ 380,000 (released in 1979)
후기형 ¥ 450,000 (around 1982)
 
정도였지만 현재 중고 가격은 상태가 좋은 경우 천만원을 훌쩍 넘어 가는 것 같습니다.
 
제가 가진 제품은 작동 상태는 아무 문제가 없지만 외관은 최상의 상태는 아니고 중간 정도로 예상 합니다.
 
일단 메이커의 설명과 그 설명의 번역입니다.
 
The L series record player was commercialized based on the R-6197 released at the Audio Fair in 1978.

A direct drive system is adopted as the drive system.
In the Direct Drive, the wow flutter characteristics have been improved by introducing a quartz lock into the servo circuit. However, the braking force generated when the needle tip traces the sound groove with a large amplitude causes dynamic load fluctuations, and the sound quality deteriorates as sound is stretched or shortened.
To solve this problem, Kenwood has developed and adopted a double LOCK system that uses quartz to lock rotational fluctuations with low frequency components and inertia to lock transient load fluctuations. This concept is also applied to the L-07D. Moment of inertia : 1.025 ton ・ cm2The turntable and dynamic compensated quartz motor control rotational variation throughout the music band.

A slotless new quartz PLL servo motor is used for the drive motor.
This motor has a built-in dynamic compensator that automatically compensates for changes in load such as changes in bearing oil viscosity to eliminate adverse effects caused by temperature changes in bearing oil. In addition, the dynamic parameter (absolute compensation value) can be changed to account for large changes in absolute value due to changes in viscosity (such as when a disc stabilizer is used).
In addition, we have adopted a double servo coupling that automatically switches the control method at ± 3% of the rated speed. When starting within 3% of the constant speed, the phase control operation provides strong torque. When the constant speed is 3% or less, the phase control operation ensures a large lock range and phase range. When the constant speed is 3% or more, the circuit coupling is automatically changed from DC to AC operation within ± 3%. This prevents the influence of motor drive circuit and motor offset and protects the constant speed.
A high-rigidity compound vibration isolation turntable composed of 3 kinds of materials is adopted for the turntable.
In this system, duralumin of 4 mm thickness is pressed on the back surface of the turn table made of aluminum die-cast, and stainless steel of 5 mm thickness (SUS 304 type) is used for the table sheet. These materials have different resonance frequencies. The resonance peak of aluminum die-cast is suppressed by duralumin and stainless steel, and the resonance peak of duralumin is suppressed by aluminum die-cast and stainless steel, so that excellent vibration damping characteristics are exhibited throughout the music band.
In addition, the stainless steel of the table sheet material is non-magnetic, so the MC type cartridge can be used without worry.

A record player has a mechanical circuit (pickup loop) consisting of needle tip → tone arm → arm base → cabinet → turntable → needle tip. The accuracy of this circuit determines the quality of the player.
In the L-07D, a hard aluminum frame is inserted between the turntable and the tone arm. In addition, a 12 φ hard stainless steel is used for the Center shaft, which is the fulcrum of the turntable. In order to reduce the viscous resistance of the thrust part due to the weight of the turntable, a magne-float system is used for the motor. In addition, the pivot of the tone arm is made of superalloy, the rotating shaft is made of stainless steel, and the bearing is a large diameter bearing that is strong against vibration, making up a strong pickup loop.

The tone arm has a laminated structure of carbon fiber, boron fiber, carbon fiber and three kinds of four layers on a pipe made of ultra-hard aluminum. By combining different materials with different resonance frequencies, highly rigid compound vibration isolation is achieved.
In addition, in consideration of the effect of the displacement between the arm pipe and the holder part, the arm pipe is not only inserted into the holder part but also a brass pipe is inserted from the inside part. The holder part has a 6-layer 4-type high-rigidity composite anti-vibration structure.

Litz wires are used in all audio signal systems to reduce audio signal transmission loss, and thick gold plating is applied to all terminals to improve sound quality.
The arm extension has 7x8 strands of 0.05 φ litz wire to reduce DCR (direct current resistance), and is fixed to the center of the pipe arm to reduce the capacitance between lines.
The audio cord has a 2-core shield structure to improve cross-auto and signal-to-noise ratio. The conductor consists of 24x7 strands of 0.08 φ Litz wire. The connector uses a 23 φ gold plated plug of special specifications. The contact area of this plug is approximately 5 times that of conventional plugs.

The arm base adopts a collet chuck system with high crimping force. In addition, the arm shaft has a large diameter of φ 27.6 mm to ensure high rigidity.
This arm base is equipped with a helicoidal height adjustment mechanism similar to precision machine lathes, and the total arm height can be adjusted by 7 mm.

The head shell adopts a high-rigidity composite anti-vibration head shell made of carbon fiber and boron fiber.
Each material has improved mechanical strength against bending and twisting by stacking the fibers in different directions, resulting in a head shell that is resistant to vibration. In addition, the shell and connector are joined together by tightening with screws and nuts, which greatly improves strength compared with the conventional caulking method.
Litz wire is directly connected to the outlet pin to reduce contact resistance by reducing one point of contact.

In order to suppress resonance frequency, a high-rigidity composite vibration-proof cabinet using three different materials is adopted.
The L-07D uses two layers of high-rigidity new ARCB material (approximately 10 kg) and mahogany complexite (approximately 7 kg) to achieve wide-range vibration isolation. In addition, the positional relationship between the tone arm and the phono motor is clarified, and at the same time, a rigid aluminum frame (approximately 2 kg), which is effective in complex vibration isolation, is inserted to achieve extremely excellent vibration isolation characteristics.

The L-07D has a structure without an insulator.
The turntable rotates with respect to the cabinet. If this cabinet is floating with an insulator, the cabinet will vibrate due to the reaction generated by the rotational energy of the turntable. The vibration of the cabinet narrows the low frequency range and degrades the transient characteristics.
The L-07D is mechanically grounded by removing the insulator to ensure high vibration isolation characteristics.

The power supply has a separate structure, and by moving it away from the pickup loop, electromagnetic induction is prevented and sound quality is improved.
The main unit has a speed selector switch and a start / stop selector switch, and the power supply section has a power switch and a dynamic parameter selector switch.

The L-07D is equipped with a J-type universal tone arm as standard, but the cabinet part is designed for second arm, and one regular size tone arm can be additional use.
The arm base for additional arm is treated as an option.

It seems that L-07D has undergone some model changes during the sales period.
The photos are from the early catalog and the later catalog, so you can see the changes by comparing them.
 
L 시리즈 레코드 플레이어는 1978년 오디오 박람회에서 출시된 R-6197을 기반으로 상품화되었습니다.

구동 방식은 다이렉트 드라이브 방식을 채용하고 있습니다.
다이렉트 드라이브에서는 서보 회로에 쿼츠 락을 도입해 와우 플러터 특성을 향상시켰습니다. 그러나 바늘 끝이 큰 진폭의 소리 홈을 따라갈 때 발생하는 제동력은 동적 부하 변동을 일으키고 소리가 늘어나거나 짧아짐에 따라 음질이 저하됩니다.
이 문제를 해결하기 위해 Kenwood는 석영을 사용하여 저주파 성분과 관성으로 회전 변동을 잠그고 과도 부하 변동을 잠그는 이중 LOCK 시스템을 개발 및 채택했습니다. 이 개념은 L-07D에도 적용된다. 관성 모멘트 : 1.025 ton ・ cm2 턴테이블과 동적 보상 석영 모터는 음악 밴드 전체의 회전 변화를 제어합니다.

구동 모터에는 슬롯이 없는 새로운 석영 PLL 서보 모터가 사용됩니다.
이 모터에는 베어링 오일의 온도 변화로 인한 악영향을 제거하기 위해 베어링 오일 점도 변화와 같은 부하 변화를 자동으로 보상하는 동적 보상기가 내장되어 있습니다. 또한 점도 변화로 인한 절대값의 큰 변화(예: 디스크 안정 장치 사용 시)를 고려하여 동적 매개변수(절대 보상값)를 변경할 수 있습니다.
또한 정격 속도의 ±3%에서 자동으로 제어 방식을 전환하는 더블 서보 커플링을 채용했습니다. 정속도의 3% 이내에서 기동할 경우 위상제어 동작으로 강력한 토크를 제공합니다. 정속이 3% 이하일 때 위상 제어 동작은 큰 잠금 범위와 위상 범위를 보장합니다. 정속도가 3% 이상이면 회로 커플링이 ±3% 이내에서 DC에서 AC 작동으로 자동으로 변경됩니다. 이는 모터 구동 회로의 영향과 모터 오프셋을 방지하고 일정한 속도를 보호합니다.

턴테이블에는 3가지 소재로 구성된 고강성 복합 제진 턴테이블을 채택했습니다.
알루미늄 다이캐스트로 제작된 턴 테이블의 뒷면에 4mm 두께의 두랄루민을 압착하고, 테이블 시트에는 5mm 두께의 스테인레스 스틸(SUS 304형)을 사용하는 방식입니다. 이들 재료는 서로 다른 공명 주파수를 가지고 있습니다. 알루미늄 다이캐스트의 공명 피크는 두랄루민과 스테인레스 스틸로 억제되고, 두랄루민의 공명 피크는 알루미늄 다이캐스트와 스테인레스 스틸로 억제되어 악대 전반에 걸쳐 우수한 진동 감쇠 특성을 발휘합니다.
또한, 테이블 시트 재질은 스테인레스 재질로 비자성이 있어 MC타입 카트리지도 안심하고 사용하실 수 있습니다.

레코드 플레이어에는 바늘 팁 → 톤 암 → 암 베이스 → 캐비닛 → 턴테이블 → 바늘 팁으로 구성된 기계 회로(픽업 루프)가 있습니다. 이 회로의 정확성이 플레이어의 품질을 결정합니다.
L-07D에서는 턴테이블과 톤암 사이에 단단한 알루미늄 프레임이 삽입됩니다. 또한, 턴테이블의 지지점인 센터 샤프트에는 12ø 경질 스테인레스 스틸을 사용했습니다. 턴테이블의 무게로 인한 스러스트부의 점성저항을 줄이기 위해 모터에는 마그네-플로트 방식을 사용합니다. 또한, 톤암의 피벗은 초합금으로, 회전축은 스테인리스로, 베어링은 진동에 강한 대구경 베어링으로 튼튼한 픽업루프를 구성하고 있습니다.
톤암은 초경질 알루미늄 재질의 파이프에 탄소섬유, 붕소섬유, 탄소섬유 3종, 4겹을 적층한 구조로 되어있습니다. 서로 다른 공진 주파수를 갖는 서로 다른 재료를 결합함으로써 매우 견고한 복합 진동 절연이 달성됩니다.
또한 암파이프와 홀더부 사이의 변위 효과를 고려하여 암파이프를 홀더부에 삽입하는 것뿐만 아니라 내부부에서도 황동파이프를 삽입한다. 홀더 부분은 6겹 4형 고강성 복합 방진 구조를 적용하였습니다.

오디오 신호 전송 손실을 줄이기 위해 모든 오디오 신호 시스템에 리츠 와이어를 사용했으며, 음질을 향상시키기 위해 모든 단자에 두꺼운 금도금을 적용했습니다.
암 연장부는 DCR(직류 저항)을 줄이기 위해 0.05 Φ 리츠선의 7x8 가닥으로 되어 있으며, 파이프 암 중앙에 고정되어 선간 정전 용량을 줄입니다.
오디오 코드는 2코어 쉴드 구조로 되어 있어 크로스 오토 및 신호 대 잡음비를 향상시킵니다. 도체는 0.08 Φ 리츠선의 24x7 가닥으로 구성됩니다. 커넥터는 특수사양의 23Φ 금도금 플러그를 사용하고 있습니다. 이 플러그의 접촉 면적은 기존 플러그의 약 5배입니다.

암 베이스에는 압착력이 높은 콜릿 척 시스템을 채택했습니다. 또한 암 샤프트는 Φ27.6mm의 대구경으로 높은 강성을 확보했습니다.
이 암 베이스에는 정밀 기계 선반과 같은 나선형 높이 조정 기구가 탑재되어 암 전체 높이를 7mm 조정 가능합니다.

헤드 쉘은 탄소 섬유와 붕소 섬유로 만든 고강성 복합 방진 헤드 쉘을 채택합니다.
각 소재는 섬유를 서로 다른 방향으로 쌓아 굽힘과 비틀림에 대한 기계적 강도를 향상시켜 진동에 강한 헤드 쉘을 만듭니다. 또한 쉘과 커넥터를 나사와 너트로 조여 결합하므로 기존 코킹 방식에 비해 강도가 크게 향상됩니다.
리츠선을 콘센트 핀에 직접 연결하여 접점을 1개 줄여 접촉 저항을 줄였습니다.

공진 주파수를 억제하기 위해 3가지 다른 소재를 사용한 고강성 복합 방진 캐비닛을 채택했습니다.
L-07D는 고강성 신형 ARCB 소재(약 10kg)와 마호가니 복합재(약 7kg)의 2겹을 사용하여 광범위한 제진을 실현합니다. 또한 톤암과 포노 모터의 위치 관계가 명확해짐과 동시에 복잡한 제진에 효과적인 견고한 알루미늄 프레임(약 2kg)을 삽입하여 매우 뛰어난 제진 특성을 구현했습니다. .

L-07D는 절연체가 없는 구조입니다.
턴테이블은 캐비닛을 기준으로 회전합니다. 이 캐비닛이 절연체로 떠 있는 경우 턴테이블의 회전 에너지에 의해 생성된 반작용으로 인해 캐비닛이 진동합니다. 캐비닛의 진동으로 인해 저주파 범위가 좁아지고 과도 특성이 저하됩니다.
L-07D는 높은 제진 특성을 보장하기 위해 절연체를 제거하여 기계적으로 접지됩니다.

전원 공급 장치는 별도의 구조로 되어 있으며 픽업 루프에서 멀리 이동시켜 전자 유도를 방지하고 음질을 향상시킵니다.
본체에는 속도 선택 스위치와 시작/정지 선택 스위치가 있고, 전원부에는 전원 스위치와 동적 매개변수 선택 스위치가 있습니다.

L-07D는 J형 유니버셜 톤암을 기본으로 장착하고 있으나, 캐비닛 부분은 세컨드 암용으로 설계되었으며, 일반 사이즈의 톤암 1개를 추가로 사용할 수 있습니다.
추가 암용 암 베이스는 옵션으로 취급됩니다.

L-07D는 판매 기간 동안 일부 모델 체인지를 거친 것으로 보인다.
사진은 초기 카탈로그와 후기 카탈로그의 사진이므로 비교해보면 변화된 모습을 보실 수 있습니다.

 
첨 보시는 분들은 매트가 없는 걸로 생각하시는데 매트 소재가 아주 무거운 스테인레스 스틸로 되어 있습니다.

 
투암을 장착한 공간이 마련되어 있습니다. 하지만 롱암은 어렵고 9인치 표준암만 추가 장착이 가능합니다. 물론 베이스를 특주해서 롱암을 장착한 경우도 있더군요.

카본 소재의 전용 헤드쉘 HS-07J 모델명을 가진 제품도 있는데 구하기도 어렵고 가끔 중고가 40-60만원 정도로 넘사벽의 가격을 자랑해서 일단은 구하는 걸 포기 했습니다. 20만원대가 딱 적당할 것 같은데 희소 가치때문에 터무니 없이 가격이 올라 버린 것 같습니다.
 
톤암 관련 스팩입니다.
 
Tonearm:
Type – Static balance type, J-shaped pipe arm, EIA connector
Effective length – 9-5/8 inch (245mm)
Overhang – 9/16 inch (15mm)
Tracking error – +2 deg 26 minutes at 150mm; -1 deg 11 minutes at 85mm; +1 deg 48 minutes at 50mm
Usable cartridge weight – 1 to 9 grams or 9 to 22 grams with supplied weight
Adjustable height range – Within 1/4 inch (7mm) by helicoid fixture (0.1mm steps)
Arm base – Collet chuck type, weight 3.3lbs (1.5Kg)
Headshell – Compression molded carbon and boron fiber, weight 12g

일본내 이 턴테이블에 대한 전문 사이트가 있더군요.
https://www.l-07d.com/

Kenwood L-07D Turntable Web site

Type	Direct drive turntable
Phono Motor Section
Drive system	Direct drive
Motor	Quartz PLL Reversible Servo Slotless DC Motor
Maximum Torque	2.5 kg / cm or More (Built-in Electronic Brake)
Turntable	33 cm aluminum die cast + duralumin composite structure, 2.9 kg
Turntable seat	Non-Magnetic Material (Suspension 303) Stainless Steel 2.6 kg
Moment of inertia	1.025 ton ・ cm2(including turntable seats)
Number of revolutions	33 1/3, 45 rpm
Wow flutter	0.01% or Less (Rotary Encoder) 0.004% or Less (FG Direct Reading Method) 0.016% or less (WRMS)
Signal-to-noise ratio	94dB(DIN-B) 65dB(JIS)
Transient load characteristics	0.00015% or Less (400 Hz, 33 1/3, 20g / cm Load) 0.00008% or Less (1 kHz, 33 1/3, 20g ・ cm Load)
Steady-state load characteristics	0% (Needle Pressure Up to 120g)
Starting / stopping characteristics	2.5 seconds or less
Rotational speed deviation	0% (out of measurement limit)
Time drift	0% (out of measurement limit)
Temperature drift	0% (out of measurement limit)
Power supply voltage characteristics	0% (± 10 V)
Tone Arm Section
Type	Static Balance Universal Type J-Shaped Arm
Effective arm length	245mm
Overhang	15mm
Tracking error	+ 2 ° 26'～、-1 ° 11'～、+ 1 ° 48' (50 mm ~ 150 mm from center)
Needle pressure variable range	0 ~ 2.0g (0.1g step)
Applicable Cartridge Weight	0 ~ 9g (when using the attached shell) 9g ~ 22g (when sub-weight is used)
Applicable Cartridge Weight	10g ~ 34g
Attached shell	Carbon Fiber Laminated Head Shell 12g
Arm height adjustment	6mm
<General>
Attachment mechanism	Static type anti-skating Helicoid type arm height adjustment Collet Chuck Type Arm Lock Large Arm Connector (With Lock Nut) Litz 2-conductor shielded audio cord Recoilless oil type arm elevation
Pwer	100 VAC, 50Hz/60Hz
Power consumption	10W (Electrical Appliance and Material Control Law)
External dimensions	Body : Width 555x Height 160x Depth 470 mm Width 555x Height 160x Depth 489 mm (maximum external dimensions, as stated in 1982) Power supply and control unit : width 130x height 110x depth 356 mm
Weight	Body : 33kg 33.8 kg (maximum external dimensions, 1982) Power supply, control unit : 4.1 kg

참고 사진들 입니다.

[야인마 2000]

와!! 저당시의 일본 턴테이블은 예술입니다.

[판돌이]

일본의 턴테이블 기술...특히 다이렉트 방식의 기술력은 굉장한 건 인정...^^