Dual 1229Q turntable

Motor and Pulley

Power for the turntable platter and the changing mechanism is supplied by a four—pole Dual continuous pole synchronous motor suspended by radially located elastic mounts and having a very small stray magnetic field and little vibration. The speed of the motor is independent of line voltage, temperature or load variations. Speed is dependent on, and proportional to power—line frequency. The motor is adapted to 50 or 60 cycle (Hz) power—line frequencies by the correct choice of motor pulley.

The motor pulley is fastened to the motor shaft by a setscrew. When you change pulleys, be sure that the new pulley is set at the correct height The turntable platter is driven by the idler wheel, which, to prevent damage to its friction surfaces, is automatically disengaged when the unit is shut off. Setting the turntable speed to 33 1/3, 45 or 78 rpm is done by raising or lowering the idler to bear against the proper step of the motor pulley. Upon actuation of the switch, the switch segment rotates. This causes the lever fitted into a slot on the segment to move vertically. The drive wheel carried on the swinging arm is then lifted off the motor pulley, moved and replaced on the motor pulley step corresponding to the selected speed.

Tonearm and Tonearm Bearing

Tubular tonearm, extra lightweight, torsionally rigid tonearm of the Dual 1229 Q pivots both horizontally and vertically on needle bearings and precision ball bearings in hardened and polished races. lt is suspended in a gimbal arrangement. This keeps friction to a minimum.

Vertical pivot friction = 0.007 gram

Horizontal pivot friction = 0.015 gram

referred to stylus tip

The arm is thus able to track extremely well. The tonearm head is removable. Before setting the tracking force for the cartridge being used, set the tracking—force scale to zero and balance the tonearm. Initial balance is by sliding the counterweight .Final adjustment is by turning the weight. You can balance cartridges with a weight of 1 to 10 grams.

To reduce the effects of small shock impulses on the arm, the counterbalance weight is resiliently mounted on a threaded spindle, and friction—braked to prevent accidental rotation. The cartridge holder will accept all cartridges with international standard mounting centers of 1/2 inch. Stylus force is set by turning a calibrated housing which stresses or releases a spiral spring contained inside. The scale adjustment is calibrated from 0 — 3 p, from 0 — 1.5 p at 1/10 p and from 1.5 — 3 p at 1/4 p intervals. Tracking forces of mors than 3 p can be adjusted with the help of the counter—weight on the tonearm; turning left (counter—clock—wise) increases the tracking force by 1/2 p per complete turn.

Specifications

Drive : Dual synchronous/continuous-pole motor, with radial elastic suspension

Platter:  Non-magnetic,  dynamically balanced

platter Weight:  3,1 kg

Platter Diameter:  305 mm

Platter Speeds:  33-1/2 ; 45 and 78 rpm

Pitch Control:  Range of variation, one semitone (6%), on all three speeds

Stroboscope:  For 33 1/3 and 45 rpm speeds. I Iluminated by special neon glow lamp

Speed Variation:  less than  ± 0.06% according to DIN 45 507

Noise (Measured according to DIN 45 500): 

Rumble 42 dB below standard signal 

Weighted audible rumble 63 dB below standard signal

Tonearm:  Torsionally rigid, extra-long tubular tonearm in four-point gimbal type bearing

Maximum Tracking Error:  0.16°/cm

Tonearm Bearing Friction (referred to stylus tip) 

Vertical : less than  0.007 gram

Horizontal : less than  0.015 gram

Tonearm Head (cartridge holder) :  Removable, accepts all cartridges weighing 2 to 10 grams and having standard 1/2" mounting centers

Current Type:  AC 50 or 60 cycle, with appropriate motor pulleys

Line Voltage:  110/130 V and 220/240 V selector

Power Consumption:  < 10 watt

Current Requirements

approx. 62 mA at 220 V 50 cycle

approx. 115 mA at 110 V 60 cycle

Dimensions (W x H x D): 14-3/4" x 3" x 12"

Weight:  7.2 kg unpacked

 

Dual 1228 turntable

 Motor and Drive

Power for the turntable platter and the changing mechanism is supplied by a four-pole, split-pole synchronous motor suspended by radially located elastic mounts and having a very small stray magnetic field as well as little vibration.

The speed of the motor is independent of line voltage, temperature or load variations. Speed is dependent on, and proportional to, power line frequency. The motor is adapted to 50 or 60 cycle (Hz) power line frequencies by the correct choice of the motor pulley.

The platter is driven by the idler wheel which is automatically disengaged from the motor pulley when the unit is shut off in order to protect its driving surface.

Platter speeds of 33-1/3 and 45 rpm are selected by raising or lowering the idler wheel to the appropriate step on the motor pulley.

Tonearm

The Dual 1228 has a light, torsionally rigid metal tonearm in a gimbal type suspension. The actual support is provided by four hardened and precision-polished steel points resting in precision ball bearings. Tonearm pivot friction is thus reduced to a minimum.

It therefore guarantees exceptionally good tracking characteristics. The tonearm head is removable. Before setting the correct stylus force for the particular cartridge installed in the tonearm head, the tonearm should be balanced with the stylus force setting dial at the zero position. Coarse balancing is accomplished by sliding the counterweight and using setcrew, after which a fine adjustment is made by turning the weight. The counterweight is proportioned so that cartridges with a weight of from 1 to 12 grams can be balanced. For the absorption of vibration and rapid small shocks, the counterweight is coupled to its threaded shaft through an elastic medium, and braked to prevent unintended rotation. The tonearm head accommodates all cartridges that conform to the internationally standard ½ inch mounting centers, and whose weight does not exceed 10 grams. Stylus force is set by turning apring housing, which is equipped with calibrations and which stresses or relaxes a spiral spring inside it. The scale is calibrated for a range of zero to 5 grams, and permits exact settings every 0,5 gram within that range.

Specifications

Drive:  4-pole synchronous motor

Platter:  Non-magnetic

platter Weight:  1,4 kg

Platter Diameter:  270 cm (10,5 inch)

Platter Speeds:  33-1/2 and 45 rpm, automatic tonearm setdown coupled to speed selector

Pitch Control:  Adjustment of approx. 1 semi-tone (6%) at both platter speeds

Speed Check:  with light stroboscope for platter speed of 33-1/3 and 45 rpm adjustable for 50 or 60 Hz

Wow and Flutter:  less than  ±0,00 % rated in accordance with DIN 45 507

Signal-to-Noise-Ratio:  (in accordance with DIN 45 500)

Better than  58 dB at rumble s/n

Better than 39 dB at rumble unweight ted s/n

Tonearm :  Torsion resistant, aluminum tonearm in universal four-point gimbal suspension

Tonearm Bearing Friction

Vertical :  <  0,008 p

Horizontal :  less than 0,18 p

Pick-up Head (Cartridge Holder):  Removable, suitable for acceptance of all cartridges having ½” mounting and a deadweight of 2 – 8 gram (including mounting fixtures)

Stylus Pressure:  Continuously-adjustable from 0 – 10 p, reliable as from 0,5 p stylus pressure

Current Type:  AC 50 or 60 cycle, with appropriate motor pulleys

Line Voltage:  110/130 V and 220/240 V selector

Power Consumption:  less than  10 watt

Current Requirements

approx. 64 mA at 220 V 50 cycle

approx. 115 mA at 110 V 60 cycle

Dimensions (W x H x D):  13" x 5" x 10-3/4"

Weight:  4,3 kg

Dual 1226 turntable

AUTO/Standard Turntable

The 1226 is likely to become known as Dual's "best buy" automatic. It shares all of Dual's standard features with the higher priced Duals, plus such refinements as the rotating single=play spindle. The platter of the 1226 is a one-piece die-casting that weighs a full four pounds. It is driven by a high torque motor which brings the platter to full speed in less than a half revolution and maintains speed within 0,1% despite wide variations in line voltage. Tonearm pivots with special low-friction bearings assure flawless tracking at as low as 0,75 gram

Specifications

Drive:  4-pole Dual synchronous motor with vertically adjustable drive pulley

Platter:  Non-magnetic

Platter Weight/Diameter:  1,45 kg or 1,8 kg/270 mm

Platter Speed:  33-1/3 and 45 rpm

Automatic tonearm set-down coupled to speed selection

Pitch Control Variation:  Adjustment range of approx. 1 semitone (6%) at all both platter speeds

Wow and Flutter (according to DiN 45 500):  

Less than ±0,12% with 1,8 kg platter

Less than ±0.15% with 1,45 kg platter

Rumble:(according to DIN 45 500)

Unweighted:  less than 38 dB

Weighted :  ,57 dB

Tonearm :  Torsion-resistant tubular aluminium tonearm in self-adjusting pivot bearing

Tonearm bearing Friction (related to stylus tip):

Vertical :  less than 0,01 gram

Horizontal :  less than 0,04 gram

Stylus Pressure:  from 0 to 5 grams infinitely variable, operable from 0,5 gram stylus pressure up

Cartridge Holder:  removable, accepting any cartridges with 1/2" ,mounting and a weight from 2 to 10 grams (including mounting hardware)

Power Supply:  110 - 130 V and 220 - 240 V, AC 50/60 Hz

Power Consumption:  less than 10 watts

Current Drain

64 mA approx. At 220 V , 50 cycle

115 mA approx. At 110 V, 60 cycle

Dimensions (W x H x D):  13" x 5" x 10-3/4"

Weight:  13 lbs

Dual 728Q turntable

Quartz PLL direct drive, fully automatic operation, and Dual's s exclusive Ultra Low Mass tonearm system

Dual exclusive features

ULM tonearm and cartridge system: less than 8 grams total effective mass

New XM300 alloy increases rigidity, reduces resonance

Hydrodynamic suspension system for tonearm, motor and platter

Turntable acoustic isolators minimize acoustic feedback and external shock

Tunable anti-resonance filter with viscous damping

HDC (High Damping Compound) housing provides high internal damping and suppresses external interference

Unique dust-cover hinges allow placement close to rear wall

 

The moment the ULM tonearms touches down on your record, you will appreciate what Dual engineers have accomplished. You will hear a purity of tone that has never before emerged from the grooves. Even if the record is warped.

 

The Ultra Low Mass. tonearm

The Dual straight-line tubular tonearm is suspended in a four-point gyroscopic gimbal which centers and balances the tonearm mass where it pivots. The vernier-adjustable counterbalance establishes zero balance with micrometer-like precision. A tempered flat-wound spring applies tracking force at the pivot - without increasing effective mass. The tonearm remains in perfect dynamic balance throughout play, even if the turntable is not level.

The ULM tonearm can accommodate cartridges weighing as little as two grams. ULM cartridges made to Dual specifications weight only 3,5 grams, including mounting bracket and hardware.

 

ULM is Dual's exclusive Ultra Low Mass tonearm and cartridge system with total effe3ctive mass less than 8 grams. That's less than half the mass of conventional tonearm and cartridge combinations.

This major breakthrough by Dual has been acclaimed throughout the audio industry, especially by the independent test labs.

These labs have begun to use warped records as 'real-life' test instruments

One lab, after making the usual measurements, also listened to a record played by the sme ULM tonearm and cartridge system. There is no way measurements, or mere words, can describe the acoustic presence, highs re crystalline, with a purity we haven't heard before. The bass is so clean that one can hear new sounds from records, such as the harmonic vibration of unplayed strings on the double bass, overall definition and transient response were outstanding.

 

Hydrodynamic suspension system

Radically new design floats the tonearm , motor and platter as one unit on four cylinders, each filled with special viscous fluid. This system absorbs virtually all spurious energy originating in sound waves as well as vibrations caused by footfalls or other movements in the room.

Two suspension systems

There are two separate and independent suspension systems, each highly effective in isolating the tonearm from acoustic feedback and other music-muddying interferences. The Hydrodynamics system floats the tonearm, motor and platter as one unit on four accordion-like shock absorbers, each filled with a special viscous fluid.

The second suspension system incorporates four tunable acoustic isolators where other turntables simply have feet. Each of these isolators is adjustable to provide maximum protection from either acoustic feedback or external shock. No more tip-toeing across the room to keep the tonearm from jumping. And no more cutting the bass to eliminate feedback.

 

Tunable anti-resonance filter

Like all other systems with mass and compliance, tonearms and cartridges tend to vibrate and cause undesirable resonances. These resonances cannot be entirely eliminated, but unless minimized they cause power-draining subsonic woofer-cone movements. You hear the results as muddy bass. Dual engineers have solved this problem with the unique tunable anti-resonance filter.

Housed in the counter-balance, the anti-resonance filter can be precisely tuned to match the tonearm to the mass and compliance of all available cartridges. The tonearm is made of the special new XM300 aluminum/magnesium alloy which increases rigidity and reduces resonance.

 

Ultra Low Mass

Hydrodynamic suspension, tunable acoustic isolators, tunable anti-resonance filter - all important contributions leading to perfection in record playback. And all Dual exclusives. Equally important, the materials, the quality control exemplify all that has made Dual precision and reliability so highly regarded throughout the world.

 

Specifications

Tonearm

Effective Length:  8-3/4"

Bearing Friction:  0,007 grams

Total Effective Mass (with ULM cartridge):  less than8 grams

Cartridge Weight Range:  2 - 9 grams

Minimum Tracking Force:  0,25 grams

Anti-skating System :  Callibred for all styli

Tunable Anti-resonance Filter: yes

Four-Point Gimbal:  yes

Motor and Platter

Motor Type:  Quartz PLL

Drive System:  Direct

Platter Size:  12"

Illuminated Strobe:  yes

Operations

Automatic Start and Stop:  yes

Manual Start and Stop:  yes

Damped Cue-control:  yes

Pitch-control Range:  11%

Rumble:  better than78 dB

Wow and Flutter: ±0,0225%

Dimensions:  17-1/2" x 15-3/16" x 5-1/12"

Dual C 901 cassette deck

Auto-reverse cassette deck

Dual's first cassette deck, the 901, incorporates every refinement you would expect of an audio component made by Dual; the precision engineering; the clean, understated design, and the quality of materials and German craftsmanship.

It also the first precision cassette deck to incorporate the convenience of automatic revers, continuous playback and bi-directional recording. Significantly, it is the first time Dual's high level of performance and reliability has been available to cassette tape recording.

 

The 901's automatic reverse-system makes it possible to play both sides of a cassette without turning it over. Continuous-play additionally permits a cassette to repeat until the machine is shut off. Recording can be bi-directional.

A photoelectric monitor actuates reversal and shuts off without drag or friction in the tape.

The 901's drive system is unique; using the time-tested Dual Continuous-Pole synchronous motor, it has separate, precision-ground belts to drive the capstan and take-up preventing tape tension variations from affecting tape speed.

The ballistically-damped VU meters of the 901 are typical of its electronic refinements. They are engineered to the exact standards specified for professional equipment.

Optimum usage of the Dolby noise reduction system is assured by a built-in test oscillator which permits precise adjustment to the magnetic characteristics of different tape types.

Other features of the 901 include:

Automatic Level Control as well as a Peak level Indicator to augment the VU meters.

 

Specifications

Tape Speed:  4,76 cm/s

Deviation from Correct Speed:  less than 1%

Wow and Flutter:

DiN 45 507 :  less than 0,12%

WRMS :  less than 0,09%

Frequency Response; 

Standard Tape :  30 - 14,000 Hz

CrO₂ tape :  30 - 16,000 Hz

Dynamic Range

IEC A-Curve :  better than 51 dB

Dolny NR :  better than 60 dB

Distortion (Ref. To 0 dB VU at 333 Hz):  less than 2%

Oscillator :  85 kHz, Push-pull Oscillator

Erasure:  better than 70 dB

Channel Separation:

Between Directions :  better than 60 dB

Between Stereo Channels :  better than 30 dB

Inputs

Mic :  0,22 mV

Radio :  0,22 mV (DIN)

RCA :  0,65 mV

Outputs:

Radio :  0,75 V (DIN)

RCA :  0,75 V

Fast Winding Time:  60 sec for C 60 cassette

Semiconductors:  4 ICs; 3 FET; 31 Transistors; 38 Diodes

Power Requirements:  110 - 130 V or 220 - 240 V, AC 50/60 Hz

Power Consumption:  approx 60 Watts

Dimensions (W x H x D):  420 x 122 x 281 mm

Weight:  6,5 kg

Dual 601 turntable

Precision and performance with the Dual 601. 

Single-play belt-drive automatic turntable

Dual's first medium-priced single-play turntable is also the first Dual to use belt drive. The drive system consists of an 8-pole synchronous motor, developed especially for the 601, and a precision belt which runs directly from the drive shaft to a flywheel rotor beneath the platter. The motor's absolute speed constancy, its exceptional smoothness, and the isolation of the platter from the motor combine to reduce wow, flutter and rumble to an insignificant level.

 

The 601 also features a special anti-skating calibration for CD-4 as well as for conical and elliptical styli.

Other unique features and capabilities include;

low capacitance tonearm leads for full compatibility with CD-4 cartridges;

a 1" dynamically balanced platter, die-cast of non-magnetic alloy;

continuous-play selector which allows the tonearm to play a record once or repeatedly;

and flawless tracking at as low as 0,25 gram.

 

Specifications

Drive:  Dual 8-pole synchronous motor through precision flat belt to platter base.

Platter:  Non-magnetic, dynamically balanced, detachable

Diameter :  305 mm

Weight:  1,3 kg (Platter with flywheel drive, 2,1 kg)

Speeds:  33-⅓ and 45 rpm

Pitch Control Variation: Adjustment range of approx. 1 semitone (approx. 6%) at both platter speeds

Speed Control (Monitoring):  with illuminated stroboscope for all platter speeds, adjustable to 50 or 60 Hz

Illuminated Strobe Sensitivity for Speed  Deviation of 0,1%:

3 bars/min at 50 cps

3,6 bars/min at 60 cps

Wow and Flutter:  less than ±0,08% (According to DIN 45 507)

Rumble (according to DIN 45 500)

Unweighted :  better than 42 dB

Weighted :  better than 63 dB

Tonearm:  Torsion-resistant tubular aluminium tonearm in self-adjusting pivot bearing

Effective Length of Tonearm:  222 mm

Offset Angle:  25° 20'

Tangential Tracking Error:  0,16 degree/cm

Tonearm Bearing Friction (related to stsylus tip)

Vertical :  less than 0,07 mN (0,007 p)

Horizontal :  less than 0,16 mN (0,016 p)

Stylus Pressure:  0 - 30 mN (0 - 3 g). Infinitely variable with 1 mN (1/10 g) calibration from 0 - 15 mN (0 - 15 g) operable from 2,5 mN (0,25 h) stylus pressure up

Cartridge Holder:  removable, accepting any cartridge with 1.2" mounting and weight from 2 to 10 g (including mounting hardware)

Adjustable Overhang:  5 mm

Power Requirements:  110 - 130 V or 220 - 240 V, AC 50/60 Hz

Power Consumption:  approx 10 Watts

Dimensions (W x H x D):  420 x 148 x 365 mm

Weight:  7,6 kg

Dual CS 721 turntable

 The Dual CS721, 

single-play direct-drive turntable with fully automatic start and stop, plus continuous repeat.

 

The new Dual CS721 is the ultimate expression of the principles that determine the performance of tonearms and drive systems. Its stright line tubular tonearm pivots horizontally and vertically within a true, four-point gimbal, thus maintaining dynamic balance in all planes.

Another Dual innovation - Vertical Tonearm Control - contributes in yet another way to fine tracking performance. A vernier height adjustment over an 8 mm range paralleles the tonearm to the record with any cartridge. This eliminates the added mass of cartridge spacers, otherwise needed to achieve precise vertical tracking angle. In all, there are seven tonearm settings and adjustments - from stylus overhang to cueing height and descent speed - all serving to optimize tracking performance with any cartridge.

The direct-drive system of the CS721 is of comparable precision. The the electronically controlled DC , brushless motor is the smoothest and quietest ever made. A major contribution to this end result is an exclusive Dual feature: two stacked coil layers, each consisting of eight coreless bifilar wound coils, that overlap to achieve a gapless rotating magnetic field. This eliminates the successive magnetic pulses typical of all other motor designs.

Although the CS721 is Dual's most expensive model, it is hardly the most expensive turntable available today.

 

The direct drive Dual EDS 1000-2 motor, which was developed especially for the hi-fi record player, is a slow-running, brushless, DC supply electronic motor which gets its energy from a regulated power supply DC motors typically employ a mechanical switching commuter, but the Dual EDS 1000-2 utilizes two Hall Generators for electronic switching Hall Generators regulate four switching transistors successively to control the four windings of the motor. This cyclic switching of the field coils produces a rotational field which then causes rotary motion of the motor. The rotary field coils produce a voltage which is measured and compared to a voltage standard. Any resultant voltage differential is fed back and regulated the flow of current in the four switching transistors to regulate speed. This system of control prevents speed errors freater than 0,025%. The Dual EDS 1000-2 motor rotor is grooveless and has a magnetic interference (short circuit terminal), which runs with the rotor.the motor field coils are non-ferrous and mounted in the air gaps among the eight pole ring magnet of the rotor and the magnetic short-circuit terminal.

The unique design described above results in distinct advantages for the Dual EDS-1000-2 Without pole sensitivity, hysteresis or turbulance current loss and without disturbing groove frequencies, the Dual EDS 1000-2 guarantees you a completely vibration-free and unusually steady drive source for your hi-fi recordplayer.

 

The tonearm of Dual CS721 meets all the requirements for today's record players; maximum rigidity with lowest effective mass, and practically negligible bearing friction in the vertical and horizontal planes.

Studies of vibrations resulting from tonearm mass, weight, and compliance of the cartridge have shown that a special design of the tonearm counterbalance can increase tracking ability considerably, namely when the tonearm counterbalance is designed to absorb vibration energies within the resonant ranges of tonearm and chassis.

For this reason, the inner section of the counterbalance is tuned to the tonearm resonance and has, due to in phase-opposed vibrations, an anti-resonance effect. By excitation of the tonearm within the resonance area - energy vibrations between tonearm and anti-resonator are eliminated. The outer part of the counterbalance, designed as a higher tuned anti-resonator, prevents the transmission of chassis resonances to the tonearm.

The design of the tonearm counterbalance with twp antiresonance filters also improves the signal-to-noise ratio.

 

Specifications

Tonearm

Torsionally rigid tubular aluminum tonearm in low friction four point gimbal suspension, tonearm counterbalance with two mechanical anti-resonance filters

Effective length of Tonearm:  222 mm

Offset Angle:  25°20'

Tangential Tracking Error:  0,16°/cm

Tonearm Bearing Friction (related to stylus tip)

Vertical :  <0,07 mN (0,007 gram)

Horizontal :  <0,15 mN (0,015 gram)

Stylus Pressure:  from "0" to 30 mN (0 -3 gram) infinitely variable with 1 mN (0,1 gram) calibrations from "0" to 15 mN (0 - 1,5 grams) operable from 2,5 mN (0,25 gram) stylus pressure up

Cartridge Holder:  removable, accepting any cartridges with 1/2" mounting and a weight from 4,5 to 10 grams (including mounting hardware)

Adjustable Overhang:  5 mm

Turntable

Drive: Electronically-regulated direct-drive system, EDS 1000-2

Power Input:  approx. 2,5 watts

Motor at Playing operation: < 50mW

Power Consumption (at Start):  60 mA (220 V 50 Hz); 110 mA (110 V 60 Hz)

Time From Start to Rated Speed:  2 - 2,5 s at 33-⅓ rpm

Platter:  non-magnetic, dynamically balanced,

Mass :  1,5 kg

Diameter : 305 mm

Total Speed Load of Drive System (rotor with platter) :  3,0 kg

Moment of Inertia:  250 kp/cm²

Platter Speed:  33-⅓ and 45 rpm. Electronically adjustable. Automatic tonearm set-down coupled with speed adjustment.

Pitch Control: for both speeds, adjustable by means of variable resitor, range of regulation: 10%

Speed Contro (Monitoring)

With illuminated stroboscope for platter speed 33-⅓

Sensitvity (of the illuminated strobe for 0,1% speed deviation

3,0 division markings per minute at 50 Hz

3,6 division markings per minute at 60 Hz

Total Wow and Flutter (DIN 45 507) : < ±0,03%

Rumble (DIN 45 500)

Unweighted :  >50 dB

Weighted :  >70 dB

Line Voltage:  110  to 125 V, 220 to 240 V

Current:  AC 50 or 60 Hz

Dimensions (W x H x D):  424 x 150 x 368 mm

Weight:  8,7 kg

Dual 1249 turntable

Single-play / multi-play , belt-drive turntable with fully automatic start and stop, plus continuous play. 

Mode selector paralleles tonearm to record in single-play for accurate vertical tracking.

True, four-point gimbal centers and pivots the tonearm mass at intersection of horizontal and vertical axes. Tonearm is dynamical balanced in all planes. The four needle-point pivot are first hardened, then honed, a process which produces microscopically smooth surfaces. The prcision ball-bearing races are only 0,157 inch diameter.

Unique "Vario-pulley" used in Dual three belt-drive models is precision-machined for perfect concentricity and balance. Speeds are adjust by expansion and contraction of pulley circumference, belt is never twisted or distorted.

 

For several years, independent surveys of component owners - audio experts, hifi editors, record reviewers, readers of the music/equipment magazines - have shown that more of them own Duals than any other turntable. This is quite a testimonial to Dual's quality performance, reliability and fully automatic convenience.

We believw the new 1249 will add even more serious music lovers to the roster of Dual owners, as it provides every feature, innovation and refinement long associated with Dual turntables plus some new ones. And all in a newly designed chassis that complements the superb design and meticulous engineering of the 1249.

The low-mass tubular tonearm pivots in a true four-point gyroscopic gimbal suspended within a rigid frame. All tonearm setting are easily made to the exacting requirements of the finest cartridges. The tonearm is vernier adjustable for precise balance, tracking pressure is calibrated in tenths of a gram; anti-skating is separately calibrated for conical, elliptical and CD-4 styli. Tracking is flawless at pressures as low as a quarter of a gram. In single play, the tonearm parallels the record to provide perfect vertical tracking. In multi-play, the Mode Selector lifts the entire tonearm to parallel the center of the stack. All operations are completely flexible and convenient - and they are foolproof. The tonearm can be set on the record manually or by using the viscous- damped cue-control or by simply pressing the automatic switch. You also have the options of single-play, continuou-repeat, or multiple-play. The dynamically-balanced cast platter and flywheel are driven by an 8-pole synchornous motor via a precision-ground belt. Pitch is variable over a 6% range and can be conveniently set to exact speed by means of an illuminated strobe, read directly off the rim of the platter.

 

 

Specifications

Drive:  Dual 8-pole synchornous motor; flat belt for flywheel drive

Starting Time:  approx. 2 sec. (33-⅓rpm)

Platter:  Non-Magnetic, dynamically balanced

Diameter :  305 mm

Weight :  1,3 kg ( platter with flywheel drive 2,1 kg)

Platter Speeds:  33-⅓ and 45 rpm. Automatic tonearm set-down coupled with speed adjustment

Pitch Control Variation:  Adjustment range of approx. 1semitone (approx 6%) at both platter speeds

Speed Control:  with illuminated stroboscope for platter speeds (33-⅓, 45 rpm)

Illuminated Strobe Sensitivity for Speed Deviation of 0,1% :

3,0 bars/min at 50 cps

3,6 bar/minn at 60 cps

Wow and Flutter:  According to DIN 45 507 (GIS < ±0,08%

Rumble (according to DIN 45 500):

Unweighted :  better than 42 dB

Weighted :  better than 63 dB

Tonearm:  torsion-resistant tubular aluminnum tonearm in four-point gimbal

Effective Length:  222 mm

Offset Angle:  25° 20'

Tangential Tracking Error:  0,16 °/cm

Tonearm Bearing Friction (related to stylus tip):

Vertical :  less than 0,07 mN (0,007 p)

Horizontal :  less than 0,16 mN (0,16 p)

Stylus Pressure:  0 - 30 mN (0 - 3 g) Infinitely variable with 1 mN (1/10 g), calibration from 0 - 15 mN (0 - 1,5 g) operable from 2,5 mN (0,25 g) stylus pressure up

Cartridge Holder:  Removable, accepting any cartridges with 1/2", mounting and weight from 4,5 to 10 g

Adjustable Overhang: 5 mm

Current:  AC 50 or 60 Hz, changeable by changing motor pulley

Line Voltage:  110 - 130 V 0r 220 - 240 V , switchable

Power Consumption:  approx. 10 Watts

Dimensions (W x H x D):  420 x 148 x 365 mm

Weight:  7,6 kg

Dual 701 turntable

The Dual 701 is the quietest turntable ever made. Not only in our judgment, but in that of the first independent test laboratory to evaluate its performance. This has been accomplished by an entirely different kind of motor, designed expressly for the 701, and by a very innovative approach to the problem of resonance.

Instead of the familiar, high-speed AC motor, the 701 has an all-electronic, low-speed Dc motor with feedback-controlled speed precision. Because this motor rotates at the record speed, 33-⅓ or 45 rpm, the need for speed-reduction systems such as friction-idler or rim-belt is eliminated. Instead, the platter is rotated directly by the motor, and the record spindle is the top of the motor shaft.

The 701 motor is so quiet and free from vibration that it does not require any isolation mounting but is mounted directly to the chassis. Dual's exclusive design of overlapping coils, a unique feature of the motor, eliminates the successive pulses common to every other existing motor, including other electronic types, high speed or low speed.

 Another Dual innovation serves to prevent interference from reaching and affecting the stylus. Two separate anti-resonance filters, each tuned to a specific resonance range, are located within the counterbalance housing.

One filter is tuned to the resonant range of the tonearm/cartridge system; the other, to the resonant range of the chassis. Each filter serves to cancel out the resonant energy that would otherwise impart spurious signal to the stylus. For those who would like to know more about the 701 motor and the anti-resonance filters.

THE Dual 701 is designed for only single play. But like other Duals, it can be operated either fully automatically, or as a manual turntable.

Because of the unique motor and anti-resonance filters, the 701 is slightly quieter than the 1229. but if you now own a 1229, or any other current Dual, you will detect only a minor difference.

Full-size twelve-inch dynamically balanced, die-cast platter

The 701 platter rests directly on the rotor and rotates with it at the selected speed. Every platter is cost from a single piece of special zinc alloy which is then individually machined and balanced while rotating at high speed. Any imbalances, however minute, are graphically revealed by computerized gauges and precisely corrected. The platter's full twelve-inch diameter, 9,7 pounds of weight (platter plus rotor) and perfect dynamic balance combine to provide optimum flywheel effect.

 

Electronically-regulated, direct-drive motor with exclusive overlapping coil system.

The EDS-1000 motor developed by Dual for the 701 is an all-electronic, low-speed, brushless, DC motor with Hall-effect feedback control, and energized by a regulated power supply. Unlike conventional DC motors, commutation (electrical switching) is not done by brushes and commutator ring. The 701 motor has electronic switching commutation and speed regulation. Two Hall-effect generators drive four switching transistors which produce a rotating magnetic field in the motor's field coils. Depending on the position of the rotor, the magnetic field causes the four magnetic pairs on the rotor to be pushed and pulled continuously. The field coil design is unique and exclusive with Dual. Two stacked coil layers, each consisting of eight bifilar-wound (coreless) coil, offset by 22,5°, achieving a gapless rotating magnetic field that eliminates the successive pulses of magnetic flux typical of all other motor designs. The absence of magnetic spring-back or other rotation irregularities can be demonstrated by turning the rotor manually, no resistance will be sensed. Also, because of the coreless field coils the motor is free of hysteresis or eddy-current losses and the disturbances of pole frequencies.

The rotational speed of the 701 motor is controlled electronically. A voltage which is a function of motor speed is fed to an electronic regulating circuit, and is compared to a constant standard voltage dreived from a regulated power supply. Any difference in these two voltages causes an immediate change in the motor current, hence the motor speed. The rotor is a barium ferrite ring magnet, magnetized in eight segments (poles) on its lower front surface. A steel plate serves as a megnetic return circuit. The regulated power supply makes the speed independent of variations in power-line voltage or frequency. Speed can be set directly to either 33-⅓ or 45 rpm. Thus, the platter is driven directly by the rotor, without need for any speed-reducing linkoge such as friction-idler or rim-belt.

Further, in contrast to the high speed (1800 rpm) vibrations of the conventional AC motor, the 701 motor is so free from vibration that it is mounted directly to the chassis without introducing any rumble. In summary, the 701 electronic direct-drive system, with its over-lapping gapless design, rotating magnetic return circuit and coreless field windings, is the most advanced drive system available for record playback today.

 

Specifications

Drive;  Electronically-controlled direct-drive system Dual EDS-1000

Platter:  Non-magnetic, dynamically-balanced, detachable

Platter Weight:  2,9 kg

Platter Diameter:  305 mm

Total Rotating Mass of Drive System (Rotor with Platter):  4,4 kg, moment of inertia 460 kp/cm²

Run-up Time:  2 - 2,5 sec on 33-1/2 rpm

Platter Speeds:  33-⅓ and 45 rpm  - Electronically switchable, automatic tonearm lowering coupled to speed change

Pitch Control:  Separate for both speed adjustable in each case with variable resistor, with setting scales, range of adjustment 8%

Speed Check:  with light stroboscope for platter speed of 33-⅓ and 45 rpm, adjustable for 50 or 60 Hz

Sensitivity Of Light Stroboscope (for 0,1% Speed Deviation):  6 graduations per minute (at 50 Hz); 7m2 graduations per minute (at 60 Hz)

Overall Speed variations:  less than ±0,03% (DIN 45 507)

 Signal-to-Noise Ratio (DIN 45 500)

Rumble Unweighted :  more than 50 dB

Rumble Weighted :  more than 70 dB

Tonearm:  Torsion resistent, extra long tubular aluminum tonearm in super flat unversal 4-point gimbal suspension, tonearm balance weight with double acting vibration damping (2 anti-resonators)

Effective Tonearm Length:  222 mm

Offset Angle:  25° 20'

Tangential Track Error Angle:  0,16°/cm

Tonearm Bearing Friction (related to stylus point)

Vertical :  < 0,007 p

Horizontal :  < 0,015 p

Tracking Force:  0 - 3 g continuously variable, with 1/10 p calibration in the range from 0 - 1,5p, reliable as from 0,25 p tracking force.

Pick-up Head:  Detachable, suitable for all pick-up cartidges with 1/2" mounting and a deadweight of 2 to 10 g (including mouting material)

Adjustable Overhang:  5 mm

Power Requirements:  110 - 130 V, 220 - 240 V, AC 50/60 Hz

Power Consumption:  2,5 watts (approx), Motor during play <50 mW

Dimensions (W x H x D):  420 x 147 x 365 mm

Weight 10,9 kg

Dual 604 turntable

The Dual 604 is direct drive turntable

You may have noticed that most turntable stories begin and end with the drive system. The tonearm is more or less an afterthought. But not with Dual. Because the tonearm can make a big difference in how records sounds and how long they last. Which is why Dual is very serious about tonearms in our article.

Let's consider the 604 tonearm

The straight-line tubular design provides maximum rigidity with minimum mass. The four-point gimbal centers and pivots the tonearm precisely where the vertical and horizontal axes intersect. And the counter balance houses, two specially-tuned anti-resonance filters that absorb parasitic resonances originating in the tonearm /cartridge system and chassis.

Operation is semi-automatic, with another uniqueDual difference: the machanical sensor. Switch it in and you feel when the stylus is positioned precisely over the 12" and 7" lead-in brooves. At the end of play, the tonearm lifts and returns to its post, and the motor shuts off Automatically.

Now let's talk about the direct-drive system. It employs a newly developed DC electronic motor, with speed regulated by a CMOS integrated circuit and digital reference circuit. Spped accuracy is within 0,001 percent. Wow and flutter are less than 70 dB, as with any great drive system, that's far beyond audibility.

But the important story with any turntable is simply this. The drive system merely turns the record. It's the tonearm that plays it.

Specifications

Drive:  Electronically Regulated Direct-drive system, Dual EDS 500

Speeds:  33-⅓ and 45 rpm, electronically adjustable

Time From Start to Rated Speed:  2 - 2,5 s at 33-⅓ rpm

Pitch Control:  Separate for both speeds, each adjustable by means of variable resistor with calibration scale of regulation; 10%

Speed Control (Monitoring):  with illuminated stroboscope for platter speeds 33-⅓ and 45 rpm, adjustable to 50 or 60 Hz

Sensitivity of the Illuminated Strobe:  6 division marking per minute at 50 Hz, 7,2 division marking per minute at 60 Hz

Platter:  Non-magnetic, dynamically balanced

Platter Diameter/Weight:  300 mm / 1,3 kg

Wow and Fluuter:  according to DIN 45 507 (GIS) less than ±0,06%

Rumble (DIN 45 500): 

Unweighted :  better than 45 dB

Weighted :  better than 65 dB

Tonearm:  Torsionally rigid tubular aluminum tonearm in low-friction four-point gimbal suspeension, tonearm counterbalance with two mechanical anti-resonance filters

Effective Length of Tonearm:  222 mm

Offset Angle:  25° 20'

Tangential Tracking Error:  0,16°/cm

Tonearm Bearing Friction

Vertical :  less than 0,07 mN (0,007 g)

Horiziontal :  less than 0,16 mN (0,016 g )

Stylus Pressure:

From 0 to 30 mN ( 0 to 3 g) infinitely variable with 1 mN ( 1/10g) calibrations

From 0 to 16 mN (0 to 1,5 g) operable from 2,5 mN (0,25 g) stylus pressure up

Power Input:  apprx. 2 watts, Motor at playing operation less than 50 mW

Power Supply:  110 V -125 V, 220 V - 240 V, AC 50/60 Hz

Power Consumption:  at Start 25 mA at Play 15 mA (220 V, 50 Hz); at Start 65 mA at Play 25 mA (110 V, 60 Hz)

Weight:  4,6 kg