Dual CS 731 Q Operating Instructions

The value for the Dual ULM 60 E is 7.8. It is recommended to
carry out tuning setting before inserting the counterbalance into
the tonearm. In this case, hold the stem with one hand and turn
the scale ring with the other.
Note
If you turn the damping selector in the range of the wedge-sha-
ped marking to stop position, the tuning anti-resonator is safe-
guarded against transport damage.
Compliance of HiFi magnetic and dynamic cartridges
Cartridge Stylus
pressure
Cartridge mass
Mounting
Car- | hard-| Total
tridge | ware | mass
[9]
Manufac-
turer
Shure VISIII 65 | 18 | 8,3
V 15 IV 63 | 18 | 8,1
M95 ED 6,5 18 |83
Ortofon | SL15Mk Il 70 | 15 185
70 15 | 85
55 1,2 10657
Audio- 68 | 12 | 80
Technica 6,2 18 | 80
5,5 18 17,3
6,2 18 | 80
7,6 | 18 | 9,4
Balancing the tonearm
Precise tonearm balancing is important, above all for cartridges
with a low stylus pressure. The tonearm need only be balanced
once. However, it is recommended to check the tonearm balance
from time to time.
The tonearm is balanced if it remains in a horizontal position
when suspended freely and if it returns to this horizontal posi-
tion if pushed upwards or downwards.
The tonearm is first of all balanced approximately by shifting
the counterbalance with the stem in the tonearm tube and then
exactly balanced by turning the front knurled wheel on the
counterbalance (1):
1. With the tonearm still locked to the tonearm post, turn the
platter a few times by hand in clockwise direction.
2. Set the stylus pressure (3) and anti-skating (4) rop" Un-
lock the tonearm and swivel above the tonearm rest.
18
3. If the tonearm does not return to a horizontal position on
its own, release the locking screw (2) and shift the counter-
balance with the stem until you have an approximate balan-
ce. The stem of the counterbalance should then be locked
by tightening the locking screw.
4. Subsequently balance the tonearm exactly by turning the
front knurled wheel on the counterbalance.
5. Set the stylus pressure and anti-skating.
Setting stylus pressure
Each cartridge requires a certain stylus pressure with which op-
timum reproduction is obtained. You will find this specification
for the fitted cartridge on the enclosed data sheet.
If the tonearm has been exactly balanced, the stylus pressure
necessary for the cartridge is set by turning the stylus pressure
scale (3). The stylus pressure can be continuously set within
the range from 2 to 20 mN (0.2 - 2 g), whereby the digits on
the scale represent the following.
1 10mN 1g
2 20mN 2g
A graduation mark in the range from 2 - 15 mN is analogous to
this (0.2 - 1.5 g) 1 mN (0.1 g).
The unit works reliably from a stylus pressure of 2.5 mN (0.25 g)
onwards.
>>
Anti-skating
The skating force acting upon each tonearm leads to one-sided
wear and tear of the stylus and record and can cause distorted
reproduction.
In order to balance out the skating force, a counterforce exactly
defined with regards to size and direction must be applied. The
anti-skating device (4) of your HiFi record player fulfills this
requirement.
For stylus types usual or standardized nowadays, separate set-
ting scales are available in accordance with the printed symbols:
O Setting for spherical styli.
© Setting for biradial (elliptical) styli.
CD 4 setting for playing CD 4 records with CD 4 special cartrid-
ges.
Adjustment of the anti-skating device should be carried out
synchronously to setting of the stylus pressure: turn the anti-
skating device to the digit of the scale concerned, which cor-
responds to the adjusted stylus pressure. For example, in the
case of 10 mN (1.0 g) stylus pressure also place the anti-skating
rotary button in position '*1””.
The skating force is reduced by approximately 30 % in the case
of "wet" playing (playing records moistened with liquid). In
this case, it is recommended to accordingly adapt the setting.
Pitch control
Each of the standardized speeds 33 1/3 and 45 rpm can be
varied with the pitch control.
If the pitch switch (21) is switched to ON, the pitch can be
varied — separately for each speed — within the range of
+ 5.5 % with the rotary controls (20) and (22).
Contrary to most quartz-controlled record players, in the case
of your Dual record player each preselected speed in the pitch
range is exactly quartz-exact and PLL controlled.
The optoelectronic analog indication (17) shows the percentage
deviation from the rated speed (Fig. 2).
If the pitch switch (21) is in OFF position, the speed corresponds
quartz-exactly to the set rated speed, independently of how
the rotary controls (20) and (22) are set.
Quartz-exact luminous stroboscope
The precise stroboscope marking on the platter edge is flashed
at with a quartz-exact frequency via an LED luminous element
(14). In this way, the indication is neither dependent on the
mains frequency nor does it need several stroboscope rings for
various speeds and mains frequencies. It is as exact as a quartz
clock.
If the graduated marking seems to stand still, both speeds have
been set to quartz precision. By means of the speed of the apparen-
tly wandering graduation marking, the speed selected with the
pitch rotary control can be determined with extreme axactness:
1 mark/seconds correspond to a deviation of 0.9 %.
If the graduated marking seems to be moving, the speed is higher
than the rated speed, if it appears to move contrary to the direc-
tion of rotation, the speed is slower than the rated speed.
Alignment of the tonearm setting down point
When the START button (12) is operated, the stylus automati-
cally lowers itself into the run-in groove of the record. If, in
the case of a subsequently fitted cartridge for example, the
stylus sets down too far from the run-in groove, the setting
down point of the diamond stylus can be corrected with the
alignment screw (10).
If the stylus sets down too far inside or outside the record,
turn the alignment screw to the left or the right accordingly.
The setting is effective not only for 17 cm but also for 30 cm
records.
The platter
The dynamically balanced aluminum diecast platter lies directly
on the motor axis and, when placed in position, is automatically
fixed through its own weight. Additional locking is not neces-
sary and is also not provided for.
Important! Remove the platter before transporting the unit!
Quartz controlled direct drive EDS 920
The newly developed quartz controlled direct drive of this
Dual HiFi record player is a synthesis of the wellknown Dual
direct drive motor principle and a highly sensitive electronic
system which receives its exactness from a quartz crystal. The
drive motor is a no-collector DC motor, in the case of which
the mechanical-electrical switchover (commutation) is carried
out by two Hall generators, which recognize the respective po-
sition of the rotor equipped with an 8-pole annular magnetand
which activate the respective winding strands of the static flat
coils. The magnetic return plate which also rotates and the an-
nular magnet surround the air-core coil arrangement with a
slight air gap so that the drive on the one hand obtains an ex-
tremely steady running behavior without any pole sensitivity
and on the other hand it obtains a powerful starting torque
despite the thrifty supply of energy.
After the rated speed has been attained, this motor needs less
than 50 mW in order to maintain rotation of the record player.
At the same time, this extremely low power consumption is
proof of the highly precise design of this drive principle and,
on the other hand, ensures that this HiFi record player is prac-
tically absolutely free from rumble.
For determination of the effective speed, the motor is coupled
with a multipole generator which supplies a frequency propor-
tional to the speed with great resolution. At the same time, a
highly stable frequency is produced from the quartz oscillator
via a divider circuit, which corresponds exactly to the generator
frequency at rated speed. Both frequencies are applied to aPLL
switching circuit and are compared there with each other. Even
if the record player is subjected to an additional load, for
example a record cleaner, the platter speed remains absolutely
constant due to this phase-locked coupling of the control
electronics.
Service
All the lubrication points have sufficient oil. Thus, your unit
will- operate impeccably for many years under normal condi-
tions. Never try to lubricate any of the lubrication points your-
self. If your record player should ever need servicing, either
take it to your specialist dealer or ask him for the address of
the next authorized Dual Servicing Workshop. Please make sure
that only original Dual replacement parts are used.
Should the unit ever be dispatched, make sure that this is packed
perfectly, if possible, by using the original packaging.
Electrical safety
The unit complies with the International Safety Regulations for
radio and related devices (IEC 65).
Technical data
Measured values = typical values.
Rumble and wow and flutter values obtained with test record.
Current type
Alternating current 50 or 60 Hz
Mains voltages
Drive
Quartz stabilized electronic direct drive system Dual EDS 920,
PLL control
Power consumption
Approximately 4 W, motor during playing < 50 mW
Starting time
(Until the rated speed is attained) approximately 1.8 seconds at
33 rpm
Platter
Non-magnetic, dynamically balanced, removable, total rotating
mass approximately 1.5 kg
Platter speeds
33 and 45 rpm, switched over electronically, quartz stabilized.
PLL technology, separate quartz-exact adjustment for both
speeds, adjustment range +5.5%
Speed control
Quartz-exact, luminous stroboscope with automatic frequency
switchover for 33 and 45 rpm
Sensitivity of the luminous stroboscope for 0.3 % speed deviation
20 division marks per minute
Wow and flutter
110 — 125 V and 220 — 240 V
DIN + 0.025 %
WRMS + 0.015%
Signal to noise ratio (in accordance with DIN 45 500)
Rumble unweighted signal-to-noise-ratio 55 dB
Rumble weighted signal-to-noise-ratio 78 dB
Tonearm
Distortion-free ‘’ultra-low-mass'”, aluminum tubular tonearm in
gimbal 4 point tip bearing.
Tonearm counterbalance with tuning anti-resonator
Effective tonearm length 221 mm
Offset angle
240 4'
Tangential tracking error
0.160/cm
Tonearm bearing friction
(Referred stylus tip)
Vertical 0.07 mN (0.07 g)
Stylus pressure
Infinitely variable from O to 20 mN (0 - 2 g), with 1 mN (0.1 g)
calibration in the range from 2 to 15 mN (0.2- 1.5 g)
Cartridge holder
Removable, optimally adapted to ultra-low-mass cartridges, with
long holder plate (in the accessories) also suitable for cartridges
with Dual recess-type cartridge assembly and for cartridges with
1/2” attachment and an own weight of 2 to 9 g (including at-
tachment material)
Adjustable overhang: 5 mm
Cartridge
See separate data sheet
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Dual CS 731 Q Specifications

General

Brand	Dual
Model	CS 731 Q
Category	Turntable
Language	English