Micro seiki bl 91 brochure

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HIGH FIDELITYATURNTABLE SYSTEMS

lllll UNIV! HMNIABH SVbIlM tARMtlSS)

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Many manufacturers have [)Pvn
promoting the direct-drive motor at
the pxpense oi precusron materials
and manufacturing techniques. While
ttiivctdrwe is capable of remarkable
speed accuracy, the system does nothmrt
toward maintaining that accuracy agamsi

thcinewtable destructive eliects of aging.
/ Our philosophy is that there is no SUbSlllUlP
[or quality, precusion and tank-like ruggedness
The BL-91 (L) turntable is the ultimate expresSion
oi that philosophy. Starting With .3 massive, thick,
12.2 inch platter and employing special-alloy taearinas
machined and polished With techniques usuatly reserved
tor turboget engines, MICROs engineers have (ievusvd an
exclusive Oil-bath damping system to support the entire
rotating assembty in comp|ele isolation irom all mecnanicat

resonances.

A precision-ground drive belt connects the rotating assembly
to the brushless, servocontrolled motor With total isolation
from motorgenerated vibration. In fact, the 8L-91 (L) is probably

the smoothest, most Vibration-tree dewce oi its kind ever built.

BELT DRIVE TURNTABLE SYSTEM (ARMLESS)

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I Rotating assembly

The massive platter sits atop an incredibly
thick. 16mm 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!

Large-sized housing that accommodates
the 16 mm diameter shaft

e Drive system

The brushless, servo-controlled motor is of the
outer-rotor design and uses sophisticated elec-
tronic circuitry to maintain speed accuracy.
The specially-engineered, lothension drive belt
is made of a carbon/urethane compound for
maximum longevity and is around to a precise
thickness of 0.45mm. Motor speed is user
variable.

X-Y view --.\V.

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270' (X!)

I Electronics power transformer

To service the servo electronics. a special
transformer with a cutless core was developed.
This extremely lowflux device reduces to near
zero magnetically-induced hum when used with
a moving-coil phono cartridge.

I Brass tanearm mounting plate
The tonearm mounting plate on the BL-91 is

solid brass. It weighs 1.5 Kilogramsl (2 kilo-
grams for BL-91L.) This plate keeps the
tonearm fulcrum rigid, assuring accurate trac-
ing angles and minimal tonearm resonances.
The standard plate will fit the following arms:

1. MICRO SElKl 2. AUDIOCRAFT

3. TECHNICS 4. TEAC

5. DENON 6. JVC
Optional mounting plates are available for SME,
GRACE and other quality arms.

I Usable tonaarms for 8L-91 mount bases

Micro MAo505X. 505$, 707x
A4201 Audio Craft AC-300MK-n, AC-300A

Technics EPA-99
A4202 SAEC HIE-308. 308NEW, 308$X
A4203 FR FR-64.645.14

Denon DA-303. 305, 307, 309
A4204 FR FR-24MK-U,54

Victor UA-5045

. AC-3000MC.

A-1205 Audio Craft 300MKII, 300A
A4206 SME 3009/51~3

I Usable tonearms for 8&9". mount bases

Micro MA-505LX, LS
SAEC WE-308L
A4501 Audio
Technica AT-1501 ][
Grace G-660P
Audio Craft ACAOOOMC
A-1502 Victor UA-7082
- -__,_ FR FIR-56$
A-I 503 STAX UA-70
A-1504 Denon DA-302, 304, 308
A-1505 Ortoion RMG-309
A-1506 SAEC WE-506/30

Mount bases for other tonearms are supplied on
a custom-made basis.

Y-Z view f-v . .2
--2--Lw-:~ .

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#4,. .f. geiiyp. transformer

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MICRO SEIKI 1:0qu

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I Turntable base

The base of the BL-91 ll.) is made completely of
multi-laminar natural woods, a dense, sturdy
design that prevents the transmission of reso~
nances and distortion caused by rotational and
torsional forces. It is finished with hand-
rubbed, natural-ebony veneer and suspended on
four sophisticated. anti-feedback feet.

SPECIFICATIONS
Drive system --------------- Belt drive
Speeds ........................ 33.1/3 and 45 RPM

(selectable)

Speed variation~-~~-~-~- User variable to 6%

Wow and flutter --------- 0.025% WRMS

Signal-to-noiseratio ----- 75d8 (DIN 8)

Drive motOr -- 4-pole. 6-slot Outer rotOr
brushless type. servo-
controlled

Platter diameter --------- 31cm l12.2"l

Platter weight ------------ 3.5kg incl. rubber mat
Platter material --------- Diecase aluminum
Platter moment --------- 600 Kg~cm2 With rub-
of inertia ber mat

Base canstruction ------ multi-laminar natural
wood finished With
hand-rubbed natural
ebony.

USA at CANADA 120V
50/60Hz: Other areas
220~240V 50/60Hz
4 Watts max.

Powe' ...........................

Dimensions Weight

8L-91-~--- 532lWl x 440(Dl x 175
ll-llmm 16kg

BL-91L--- 600lW) x 472lDi x 186
(H) mm 22 kg

Design and specriications are subiect to modi-
fication without notice.

El type core

Flux comparison between El type
transformer and cut-less transformer
under same standards and conditions.

Printed In Japan