Mørch DP-8 Chrome Tonearm

Available in Precision 9" or 12" lengths, 6g or 14g tube weights

While playing a record, the tonearm must be able to move both horizontally and vertically – horizontally as the cartridge moves towards the center of the record, and vertically to allow for imperfections (warps and bumps) in the record.

At very low frequencies the modulation in the record is only horizontal. If the tonearm can move too freely horizontally the low frequency motion of the stylus will be transferred to the cartridge itself, while the cantilever of the cartridge almost does not move, and thus only a weak signal is induced.

To have excellent audio reproduction at these low frequencies, the horizontal movement of the tonearm must be restricted – but to ensure perfect tracking this must be achieved without a similar restriction of the vertical movement. This “anisotropic” principle – different characteristics for different directions of movement – is the essence of the MØRCH DP-8.

The DP-8 has a flywheel shaped central body and two weights on the sides to stabilize the movement of the tonearm horizontally. Thus, as the cartridge moves towards the center of the record, it can only follow the average location of the groove. It cannot follow the modulation, which is all transferred to the cantilever. This means that all the recorded bass, even the very low end of the range, is reproduced with full amplitude and dynamics.



DP-8 with 9” PRECISION armtube. It is the two weights on each side of the heavy central body of the tonearm that provides for the majority of the effective mass (Inertial moment) for the horizontal mode of motion. The center of gravity of these weights are pointing backwards – either upwards or downwards, so that they contribute to the counterweights at the same time as they provide for moving the center of gravity of the movable part of the tonearm up or down.



Here the DP-8 is shown with a 12” armtube.


Model DP-8 has a unique combination of bearings: For the horizontal mode of motion a silicone damped high precision ball-bearing assembly increases the stability provided by the large housing and sideweights. For the vertical mode of motion two precision sapphire bearings are incorporated.
The vertical motion also may be damped if desired, by injecting silicone fluid into a well. Vertical damping is rarely needed for this model. It is independent of the damping of the horizontal mode of motion, and further it can be adjusted to all intermediate levels of damping.

Model DP-8 has an integrated device for adjusting the VTA while playing. Markings for "getting back" to a special setting is provided.

The feature with different weights of armtubes to optimize the tonearm for any cartridge is maintained. Thus warps will not influence the tracking force, and there will be no vertical deflection of the cantilever.

In model DP-8 the azimuth adjustment for perfect channel separation is accomplished at the pivot of one of the sapphire bearings.

Supplied in CHROME- or 24 carat GOLD finish.
The armtube plating being made without the use of magnetic materials.

Technical specifications: Mørch DP-6/DP-8/UP-4

Construction: Radial arm with interchangeable arm tubes.
Bearing principle: DP-6 and DP-8: Dual bearing
UP-4: Unipivot.
Effective mass of complete tonearm with arm tube:
Light (green): 4 g
Medium (red): 7 g
Heavy (yellow): 8 g
Extra heavy (blue): 14 g
All arm tubes can be used with all models.

Fundamental resonance (depending on arm tube): 8 - 16 Hz (for DP-8 N/A for the horizontal mode of motion)
Tracking force (when using calibrated scale): 0 - 3 g
Bias compensation: Watch spring with string - adjustable while playing.
Azimuth: Azimuth is adjustable for correct channel separation.
Cueing mechanism: Piston in U-pipe, damped with silicone fluid.
Distance between pivot and center of turnable platter: 212 mm (8 5/16") or 294.1 mm (11 9/16")
Diameter of hole for mounting arm base: 20 mm (13/16")
Rear overhang from pivot: 70 mm (2 3/4")
Weight of DP-8 arm base w/sideweights w/o counterweights and cord: 580 g
Weight of DP-6 arm base w/armbush w/o weights and cord: 280 g
Weight of UP-4 arm base w/armbush w/o weights and cord: 240 g
Weight of a set of counterweights: 120 g
Effective length: 230 mm (9 1/16")
Offset angle: 24 degrees.
Lateral tracking error: 0 degrees at 66 mm and 120.9 mm from center of record.
Pivot point: Pivot point is in level with the record surface.
Bearing Friction: Bearing friction less than 0.04 mN in all directions.
Balancing: Four (4) different balancing weights.
Internal wiring: 19 strands of ultra pure silver insulated with Teflon.
Capacitance per channel: 28pF for all models.
Tonearm Cord: Balanced. Extremely purified copper strands that are heavily silver coated. Halogen free insulation.
Moerch tonearm connector with Cardas RCA connectors.
Capacitance per channel: 100pF.
Terminals: All terminals throughout the arm are gold plated.
Bearing concept of model DP-6 and DP-8: One internally damped, precision ball-bearing assembly for the horizontal plane of motion. Two pivoted sapphire bearings for the vertical mode of motion which can be damped also, if desired, and then adjusted to different levels of damping.
Bearing concept of model UP-4: Hardened steel pivot resting on a concave sapphire, and damped for all motions with silicone fluid.
DP-6 and DP-8 finish: 24 carat GOLD or CHROME.
UP-4 finish: CHROME or at special order GOLD.
The right to change specifications without notice is reserved by the Manufacturer.

Reviews:
Read Robert E Greene's TAS blog here