TechDAS Air Force Two Premium
TechDAS Air Force Two Premium
Technology used in vinyl reproduction
Descended from the flagship model, the core mechanism contained in the exquisite design concept is designed in such a way to exploit the aerodynamic force equivalent to sound energy to the full. It is a well-known fact that an analog disc is a sensitive and very fragile program source in which waveforms transmitted as air vibrations generated by the original music are imprinted into a microgroove in the record.
The turntable should thus be the key center of the playback process by extracting the original oscillatory waveforms in an authentic way and transmitting these as accurate audio signals. Any signals other than these valuable micro waveforms imprinted on the disc ought to be detected by a stylus as maleficent without exception.
There are specific examples such as frictional vibrations caused by bearings under a rotating turntable platter, vertical vibrations of a tonearm caused by warpage of an analog disc, or vibrations due to some stylus movement resonating with an even flat disc to the contrary and in addition to them, direct vibrations from the floor propagating directly through a turntable. There are surprisingly a constellation of maleficent vibrations. In early turntable design various attempted procedures have been rendered such as improved machining method for bearings, putting a stabilizer weight on the disc plate to reduce warpage and resonance, and supporting the overall player on springs. Results were mixed, it is a fact that no one could completely accomplish all their their objectives, until today.
The air bearing & disc suction
Two key factors of “Air Force” descended from the flagship reference. An Air Bearing Mechanism and a Vacuum Disc Suction Mechanism.
It is as always the highest-priority issue on a turntable to obtain accurate and noise free stable rotation. Since sufficient inertia is required to actualize the stable rotation, a platter is needed to be very heavy. Accordingly the “Air Force Two Premium” is now equipped with 34kg of platter. On the other hand, however, with such an extreme platter load on the bearings this can it can cause a deterioration of the bearing over time time and cause friction vibrations or degradation of rotation accuracies even with this best quality materials and most precision engineering.
One of the key mechanisms of “Air Force Two” which descended from the flagship reference is the Air Bearing Mechanism. Because of this, all the issues surrounding the use of an extremely heavy platter have been completely resolved. This system is configured with no conventional bearings and a platter simply installed on the glass plate with a polished flat surface to be aligned with the center shaft for positioning. At this stage, the platter is absolutely still, but once the ancillary electric air pump starts forcing air into the turntable, the platter is floated instantly to the height of 0.03mm (30μ) above the base and rotates in deep silence and with absolute smoothness, all due to the air bearing mechanism. As the platter load is no longer applied anywhere, frictional noise or various vibrations are perfectly eliminated and performance of highest quality is infinitely maintained.
Another key aerodynamic-force-dependent mechanism is a vacuum disc suction system. Even though the platter is rotating in extremely quiet manner and with maximum accuracy, vinyl warpage may cause a vertical motion of a tonearm and at the same time undesired stylus movement will induce sympathetic vibrations. Under such circumstance, the music signal is not extracted with complete fidelity. Longterm undesired vertical motion by the tonearm can cause the stylus to be seriously damaged. Sympathetic disc vibrations may lead loss of music signal quality and its sensitivity. It was fashionable to apply a stabiliser weight on the disc as a solution in the past. With that method it does neither give sufficient solution on disc warpage, nor suppress the development of resonance.
On the other hand, with TechDAS's vacuum disc suction system, right after setting a disc on the platter, just one press on SUCTION button located in the main unit, ensures the vinyl is sealed on the platter simultaneously with it floating on the air bearing. You can see this happen in a split second. As a result, a completely flat disc surface allowing the platter to keep rotating in a perfect environment where the vertical motion of the tonearm disappears and the potential capability of the cartridge exerts its performance to the full. It then becomes possible to extract the valuable music waveforms imprinted in the groove with the highest fidelity. After playback, a press on the SUCTION button again instantly releases the platers vacuum hold on the vinyl.
A new hybrid suspension system
While, one more aerodynamic force is Hybrid Spring Suspension. This system is newly developed for the “Air Force Two”
One of the touchy issues for a turntable is how to isolate it from vibrations propagating through floors. There often occurred different vibration problems when a turntable was installed on the floor even finished with vibro-isolating materials, because vibrations by speakers or people’s movement might propagate through the same floor. To prevent those symptoms in the past, various corrective actions like isolation by springs or buffer materials were applied to many products. However, as all of you may know, we have barely seen successful examples where there was no wobbling. In the process of developing the flagship reference, TechDAS decided to employ a hybrid suspension system configured with the air and the macromolecular polymer as the third key mechanism that resulted in an elegant solution of this particularly difficult challenge.
However, in contrast to the “Air Force One”, as the total weight and its distribution of the “Air Force Two” are different, it is not always technically suitable to employ the same system. Therefore, instead of three-legged structure, they needed to develop a new suspension system with four-legged structure which accommodates upper chamber sealed with air and lower rubberoid diaphragm with built-in springs and sealed with oil internally. That diaphragm is connected to the upper chamber via a tiny hole of the orifice plate and damps the spring movements mutually by internally sealed oil and air from the chamber and as a result, produces a high vibration insulation effect by means of reducing Q-factor of resonance. This means that the “Air Force Two“ is the same system as the “Air Force One” in terms of exploiting air force effectively for quality, and even better and easier to use for longstanding audio.
The key to achieving a significant cost reduction without a sacrifice in performance was achieved by using precision aluminium castings for the chassis
The critical issues in design for the “Air Force Two Premium” are to achieve price reduction and to ensure the existing performance on par with the flagship reference, the “Air Force One”. To manufacture the chassis of the “Air Force One” incurs many costs due to cutting a metallic block by a computerized numerically controlled (CNC) machine, TechDAS have successfully switched to an aluminum precision-casting and painting the chassis instead.
As casting is not only integrally molding the whole of a chassis mechanism but also produces a better volume-production, TechDAS have successfully accomplished significant cost reduction without sacrifice of performance. The chassis, supported by four large legs, is of a double-layered structure consisting of an upper layer with complex configuration and a flat but thick lower layer. To ensure sufficient strength, not only the thickness but also structural ribs are employed accordingly. As a result, the total chassis weight reached 32.6Kg. The heavy chassis coated in a classic and bobust hammertone finish firmly supports the fundamentals of music and sound.
Evolutionary improvements from the standard Air Force Two with a new gunmetal platter
The aim in developing the Air Force Two Premium was to achieve almost the same level of musicality as the flagship the Air Force One Premium. To this end TechDAS looked at the material of the main platter. The Air Force One uses a stainless steel main platter while the standard Air Force Two uses a platter made of aluminium. Since the beginning of the standard Air Force Two, it has been found that the difference in material of the platter is even more critical for tonality than the difference in weight. This is why TechDAS began testing new materials.
As a result of various experiments, gunmetal was chosen for the platter of the Air Force Two Premium. This material is an alloy of copper and tin, and was often used in audio equipment in the heyday of analog audio. As gunmetal is relatively soft and tensile, a subtle glow is added to the sound while its heavy weight further increases the scale of the sound stage.
The platter for the Air Force Two Premium is precision cast and surface polished with a solid construction, unlike most conventional gunmetal platers that have a hollow construction. The result is a plater of huge mass, some 34 kg.
As the “Air Force Two” is a arm-free designed turntable, no tonearm is incorporated. The chassis can mount two tonearms at the same time and both 10 inch type or 12 inch type can be accommodated. Standard tonearms with the effective length of 10 inches can be mounted on the right side of the turntable within standard specifications, but also an optionally available arm base for the second tonearm can be installed on the far left of the chassis where a tonearm with the effective length of 12 inches can be mounted. Therefore, both types can be mounted on the turntable. Since additional work is required for each mount to meet individual specifications, the particular tonearms of your choice should be communicated to us prior to the placement of your order.
The Air Force Two control unit
Needless to say that a dust is a great enemy to the analog record. However a large dust cover to cover a whole body bothers some when removing or putting on obviously. Althoug it is possible that dust on the platter can be transferred to the back of an analog disc if not using a dust cover. To resolve this problem the acrylic dust cover (which only covers the platter surface) is designed to negate dust and is included as standard for the Air Force Two Premium.
The fabric belt drives the heavyweight platter made of solid gunmetal material. The rotation is supervisory-controlled through a non-contact sensor and a microcomputer resulting in a very high rotational accuracy.
The turntable platter reaching a weight of 34Kg is manufactured by precision cutting a solid aluminium block (A5056). In analogy with the flagship model, the platter of the “Air Force Two” is equipped with a vacuum disc suction mechanism. In addition, the disc-absorption surface of the upper platter is covered with special thin film damping materials. The rotation of the platter is driven by a fabric belt. The belt being a non-stretch polyurethane fiber material with polished surface the same as employed on the flagship “Air Force One”. Please note that a common rubber belt seems much easier to handle than this belt when replacing. However, to achieve the highest grade playback, with the high-precision heavyweight turntables like the “Air Force One” and the “Air Force Two” belt-drive by a common rubber belt will obviously cause a loss of performance due to its elasticity and as a result the most convincing sound quality is not attainable.
The motor drive incorporated in the Air Force Two Premium is a high-precision AC synchronous motor stored in free-standing rugged aluminium housing. The power supply is stored in the stand-alone Air pump & Power supply Unit. A sophisticated Rotation Control System watches and controls the rotational speed of the platter through non-contact sensor and maintains a constant speed through speed adjusting microprocessor circuit. The outcome of using this combination of systems including the previously mentioned “Air Bearing System” a high rotational stability with less than 0.03% wow and flutter accuracy is achieved. Switching the speed between 33 1/3 rpm and 45 rpm is easily available from the digital front control panel.
The “Air Force Two Premium” is configured with a turntable main body, a driving motor in free-standing housing and the additional “Air pump & Power Supply Unit” in a separate case.
In the Air Pump & Power Supply Unit an electric air pump, an air condenser and power supplies for the circuits are installed. The motor-powered air pump enclosed in a robust die-cast case provides incomparable quietness with conventional simplified vibration motors and as an additional configuration a unique rubber suspension is employed for scrupulously cutting-off micro vibrations. This drive motor is combined with the air condenser which is a tempered glass chamber mechanism where air evacuated from the air pump is stored temporarily and after absorbing the pulsating air flow completely, the processed air is then fed the the turntables internal the air bearings and the vacuum platter. Other than the above mechanisms, an additional 4 distinct power supplies for the motor drive, rotation control circuit, an operating circuit and for LED light are enclosed in the unit. By having each part is fed a with a specialised dedicated power supply it ensures quality and stable power to enhance the performance of each part. By also isolating those power supplies from the turntable's main body, the possibility for electric interference on the faintest music signals is negated enabling the realisation of superior playback.
Platter surface cover “The Platter Top”