Belt Drive
Turntable System (Armless)
Many
manufacturers have been promoting the direct-drive motor at the expense of
precision materials and manufacturing techniques. While direct-drive is capable
of remarkable speed accuracy, the system does nothing toward maintaining that
accuracy against the inevitable destructive effects of aging.
Our philosophy is that there isno substitute for
quality, precisoin and tank-like ruggedness.
The BL-91
(L) turntable is the ultimate expression of that philosophy. Staring with a
massive, thick, 12,2inch platter and
employing special-alloy bearings machined and polished with techniques usually
reserved for turbojet engines, Micro's engineers have devised an exclusive
oil-bath damping system to support the entire rotating assembly in complete
isolation from all mechanical resonaces.
A
precision-ground drive belt connects the rotating assembly to the brushless,
servo-controlled motor with total isolation from motorgenerated vibration. In
fact, the BL-91 (L) is probably the smoothest, most vibration-free device of
its kind ever built.
Rotating
Assembly
The massive
platter sits atop an incredibly thick, 16 mm main shaft. Its concentricity is
machined to within 0,4 microns. The bearing material is a special alloy
lubricated by and suspended in a unique oil-bath damping system. Not only does
the system negate the need for periodic user lubrication, it is unaffected by
temperature changes and aging.
Drive System
The
brushless, servo-controlled motor is of the outer-rotor design and uses
sophisticated electronic circuitry to maintain speed acciracy. The
specially-engineered, low-tension drive belt is , made of a carbon/urethane
compound for maximum longevity and is pround to a precise thickness of 0,45 mm.
Motor speed is user variable.
Electronics
power Transformer
To service
the servo electronics, a special transformer with a cutless core was developed.
This extremely low-flux device reduces to near zero magnetically-induced hum
when used with a moving-coil phono cartridge.
Turntable
Base
The base of
the BL-91 (L) is made completely of multi-laminar natural woods,a dense, sturdy
design that prevents the transmission of resonances and distortion forces. It
is finished with hand-rubbed, natural-ebony veneer suspended on four
sophisticated, anti-feedback feet.
Brass
TonearrmMounting Plate.
The tonearm
mounting plate on the BL-91 is solid brass. It weighs 1,5 kg (2,0 kg for
BL-91L). This plate keeps the tonearm fulcrum rigid, assuring accurate tracing
angles and minimal tonearm resonances.
The standard
plate will fit the following arms; Micro
Seiki, Audiocraft, Technics. Teac, Denon, JVC
Optional
mounting plates are available for SME, Grace and other quality arms.
Specifications
Drive
System: belt drive
Speeds
(selectable): 33-1/3 and 45 rpm
Speed
Variation: User variable to ±6%
Wow and
Flutter: 0,025% WRMS
Signal-to-Noise
Ratio: 75 dB (DIN B)
Drive
Motor: 4-pole, 6-slot outer rotor
brushless type, servo-controlled
Platter
Diameter: 310 mm (12.2")
Platter
Weight: 3,5 kg (incl. Rubber mat)
Platter
Material: Diecase aluminum
Platter
Moment of Inertia: 600 Kg-cm² (with rubber mat)
Base
Construction: Multi-laminar natural wood
Finished: Hand-rubber natural ebony
Power
Requirements: 120, 200 - 240 V 50/60 Hz
Power
Consumption: 4 Watts max.
Dimensions
BL-91 / BL-91L (W x D x H): 532 x 440 x
175 mm / 600 x 472 x 186 mm
Weight BL-91
/ BL-91L: 16 kg / 22 kg