Technics Grand Class SL-1200GR2, SL-1300G, and SL-1200G
SL-1200GR2
The SL-1200GR2 marks the start of a new generation of direct drive turntables with an improved motor-drive circuit centered on the newly developed ΔΣ-Drive (Delta Sigma Drive) and a new power supply for an exceptionally low noise floor.
The SL-1200GR2 inherits a similar motor design philosophy as the SL-1200G but uses a new design with a single-rotor, surface-facing, coreless direct-drive motor. Although both players feature a coreless motor (which uses coils without an iron core), the two designs are pretty different.
Whereas the SL-1200G uses a heavy and super-sturdy low-gravitational force two-rotor system that bolts to the platter, the SL-1200GR2 looks more similar to the classic designs with a round permanent magnet fixed to the platter, which floats on top of the coils mounted underneath a printed circuit board. The platter is a two-layer design, lacking the brass top layer but retaining the rubber damping layer underneath.
The platter achieves high rigidity and vibration-damping characteristics by using a two-layer construction with deadening rubber applied to the entire rear surface of the aluminum die-cast. To increase the inertial mass and reduce vibration, the shape of the aluminum die-cast portion was optimized by simulation. At 2.5 kg (including the rubber mat), the SL-1200GR2 platter is 0.8 kg heavier than that of the previous SL-1200MK5. Also, the back surface of the platter has strengthening ribs added to improve rigidity. Increasing the contact surface area with the deadening rubber achieves damping characteristics more than twice those of the SL-1200MK5.
The SL-1200GR2’s platter seems similar to the classic SL-1210MkII’s platter until you turn it around.
The new platter shown above has a large magnet attached directly to it, just as the classic player did, but the shape is very different from the one used for the classic player, as shown below.
Likewise, the motor design is very different between the two players.
Instead of the classic player’s green iron electromagnet poles (shown above), the new player (shown below) has a neat flat circuit board printed with what looks to be speed detection or feedback coils. The actual drive coils (with no more iron cores) are mounted invisibly underneath.
Compared to the SL-1200G’s four-layer chassis, the SL-1200GR2 has a simplified two-layer BMC and aluminum die-cast construction.
The ΔΣ-Drive (Delta Sigma Drive) is a new system that applies Technics’ expertise in PWM signal processing. In addition to reducing high harmonics, the new drive suppresses motor vibrations for smoother, more accurate rotation.
A high-speed switching power supply ensures a stable capacity and less ripple and humming. It also eliminates the need for a large transformer and countermeasures for the ensuing mechanical vibrations and a switching frequency above 100 kHz limits the impact of noise on the music playback bandwidth.
In addition, the SL-1200GR2 features Current Injection Active Noise Canceling. This technology combines a noise detection device with an error amplifier, which detects residual noise in the power supply and applies an inverse phase current to remove noise components. This system is said to remove low-frequency noise more effectively than a regulator.
Interestingly, the Silent Power Supply, Active Noise Cancelling, and ΔΣ-Drive are not mentioned for the SL-1200G. However, Technics does mention that the player’s coreless motor and heavy motor/platter construction eliminate cogging, which, to my understanding, was the main aim of the redesign.
It remains unclear how the heavy construction of the earlier-generation non-ΔΣ motor system of the SL-1200G compares to the lightweight latest generation Silent ΔΣ SL-1200GR motor system when it comes to the smoothest rotation. Perhaps the two achieve a similar calmness and smoothness by different means, one using (more expensive) mechanical means and the other using (more cost-effective) electrical means, or perhaps there is (also) a bit of marketing speak going on. The listening tests will surely tell us more.
The SL-1200GR2’s connection block does not feature milled-from-brass terminals as with the SL-1200G, but they are still high-quality gold-plated phono terminals within a metal shielding construction inside the case. The power cable is detachable, with the connector mounted in an easier-to-reach straight manner rather than sideways, as with the SL-1200G.
The S-shaped tonearm used for the SL-1200GR is made of aluminum and looks very similar to the earlier tonearms. A high initial-motion sensitivity of 5 mg or less is achieved through manual assembly and adjustment by skilled Japanese artisans.
When comparing the tonearm SL-1200G VTA ring (to adjust Arm Height/Stylus Rake Angle) to that of the SL-1200GR2, the steps on the scale are not the same. The manual confirms that a setting of 1 equals a setting of 4 on the SL-1200GR2 to accommodate an 18mm Cartridge Height.
The player is supported by high-damping silicon insulator footers, made of plastic, just like the earlier players, rather than aluminum, as with the sl-1200G.
Next: SL-1300G Description
