Micro Seiki DQX-500 Turntable
There are many good features about this up-market turntable unit from Japan and, as a glance at the photograph will confirm, quite a few things missing. For a start, there is no conventional cabinet or plinth. Instead, the Micro Seiki DQX-500 has a black circular chassis with an integral platform sticking out as the arm pedestal. The diecast chassis is unusually heavy and measures 350mm (13-3/4 inches) in diameter as does the rotating platter. Making the platter this much larger than an LP record may seem a little perverse at first, but it does make a terrific flywheel effect possible. The mass, an enormous 2.6 kg (5.72 lb) in this case, allied to a large radius must do much to iron out speed fluctuations.
The quartz-locked PLL direct-drive motor must be quite powerful to overcome all this inertia, and it performed perfectly during all the tests. The start-up is on the slow side, however, at about 4 second s to reach proper speed. There is no stroboscope (why check on the accuracy of an incredibly accurate quartz crystal?) but a red standby lamp on the 33-1/3 | 45rpm speed selector goes out when the speed is correct. The platter will continue to revolve for about 25 seconds after switching off (33 seconds from 45rpm running) unless you stop it by hand. The power unit is a separate 260 x 85 x 60mm plastic box, with the advantage of keeping hum-bearing mains voltages away from the pickup. Yet some people may find it a nuisance to accommodate. The power unit has a mains on/off push button and red LED indicator. The aforementioned speed selector lever is mounted on a small platform sticking out below the platter and has a central 'off' position.
The only other control is integral with the pickup arm and comprises the usual lift/lower lever, operating a viscous damped platform with rubber top to prevent side-slip during cueing. The arm is beautifully designed and finished. It is a dead straight design, with a skeletal heads hell platform set at the required offset angle. The main counterbalance weight screws on a wide thread to achieve free balance, and the desired playing weight, which is applied by means of a torsion bar spring system, is simply dialed on a knob calibrated in 0.1g steps up to 3 grams. Another knob similarly applies an outward torque by way of sidethrust compensation (antiskating).
An unusual feature is the provision of an extra rider weight to be attached to the front portion of the arm to increase its effective mass. Much of the design effort on pickup arms in recent years has been aimed at reducing arm mass. This is deemed desirable for a number of reasons, not least because the product of arm mass (including arm, heads hell and cartridge) and cartridge compliance dictates the main low frequency resonance. As cartridge compliances have got higher, a lower arm mass has been essential to keep the resonance frequency around the optimum 10 Hertz region. (Up around 20Hz can begin to cause audible effects and react to programme signals on some discs; down around 5Hz the arm will be plagued by warp bounce.)
In an opposite trend, however, moving-coil cartridges in particular are now coming along with quite low compliance values, making an ultra-lightweight arm unsuitable. In acknowledgement of this, Micro Seiki have designed their arm to suit medium to high compliance cartridges, which they say "includes virtually all moving magnet cartridges", and recommend fitting the extra weight for low compliance (mainly moving-coil ) types. Remembering that the effective mass will be a function of this added weight multiplied by its distance from the pivot, the arm shaft is marked with numbers up to 10, and the weight should be placed at higher marks for the lower compliance cartridges. A sub-weight is screwed into the back of the main counterbalance shaft when this extra weight is in use.
How it performed
Setting up the DQX-500 and connecting it to a good quality system was very straightforward, aided by the admirably clear operating manual. The three rubber feet have no height adjustment but this is not a serious omission since a reasonably level surface should be available. They have been designed to be sensibly floppy to give a very low total resonance and this showed as achieving a useful degree of isolation from external bangs and acoustic feedback. I tried various cartridges and head-shell installation was helped by the plastic 'overhang gauge' supplied, and the slots for the mounting screws. Care was needed to line up the stylus tip with the gauge markings but, when this was done, I found that tracking error was nowhere worse than about 1.25° and was close to zero a t the inner grooves.
In sum, this Micro Seiki DQX-500 turntable has obviously been designed with the hi-fi enthusiast in mind. The ordinary record collector will miss such features as auto-stop, speed adjustment (perhaps) and a cabinet - though a moulded, clear plastic dust cover is provided. However the hi-fi man will find that the unit does constitute a rock steady playing platform with almost zero wow and very low noise (rumble and hum arc both extremely low). The arm is of excellent design, slightly favouring the present vogue for moving-coil cartridges. The price, though on the high side, corresponds with that of the competition when the combination of a quartz locked direct-drive motor and a respectable pickup arm is borne in mind.
