Moerch UP-4 Tonearm
Mørch UP-4 Uni-Pivot tonearm
The Model UP-4 incorporates a special concept within the uni-pivot principle. The bearing consist of a hardened steel pivot resting in a concave, polished sapphire. The bearing is damped in all directions with silicone fluid. The low positioning of the bearing provides for a greater stability compared to other uni-pivot arms, since a considerable part of the moveable mass of the arm is positioned above the pivot point.
With the model UP-4 the azimuth adjustment is made by the way of the counterweights.
As with all Moerch tonearms the UP-4 tonearm has the facility of interchangeable arm wands.
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
|Effective mass of complete tonearm with arm tube:
Extra heavy (blue):
|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.
The Danish Mørch UP-4 is the unipivot relative of the DP-6, which I reviewed in Issue 49 with great enthusiasm. The DP-6 has knife-edge vertical bearings and roller, ball-bearing horizontal ones, while the UP-4 is a true (damped) unipivot. Actually, the UP-4design is the earlier of the two, but the DP-6 was new at the time of review, and got all my attention. (Both arms remain available.) Although it has a different set of sonic virtues from the DP-6, the UP-4 has virtues indeed; and at its low price, it offers extraordinary value.
Unipivot pickup arms as a class have some advantages over other types: In particular, unipivot bearings have virtually zero friction and high structural bearing rigidity. Moreover, this rigidity is forever–a unipivot does not loosen with time and wear. On the other hand, unipivots are a little tweaky as to setup, since azimuth adjustment is controlled by the position of balance weights. In the UP-4, the counterweight itself is mounted eccentrically so that rotation of it one way or the other shifts the equilibrium azimuth of the arm. (If that sentence fails to make sense, please just take my word for it that the adjustment is tricky to make but stable once made.)
Like-the DP-6, the UP-4 comes with interchangeable arm tubes of various masses. With the lowest mass tube, it is compatible with the highest compliance cartridges, and indeed the arm in this configuration has the lowest effective mass of any currently available arm that I am aware of. At the other end of the spectrum, the highest mass tube makes the arm compatible with low-compliance moving coils. (For how to figure out the arm mass you need for a given cartridge, see the explanation in the box below.) This adjustable mass feature is really nice–the mass/compliance match-up is crucial sonically, and is unlikely to come out just right by accident!
All the Mørch arm tubes, regardless of mass, are designed to be low in resonance, and, indeed, sound that way. The UP-4 has a low level of arm-induced coloration, to my ears. And the sound is clear and detailed. Tracking is excellent, enhanced by the mass matching feature. Actually, in many respects–especially clarity and retrieval of detail–the UP-4 is fully competitive with more expensive arms. Where the UP4 loses out to its big brother DP-6 of the Mørch family is in control of cartridge energy, or so one gathers. Cartridges try to vibrate as they play, and it seems that the DP-6 is a bit better at restraining this. The UP-4 sounds a bit light-bright, by comparison as a result–only a bit though, and not to the point of sounding splashy or toppy.
Actually, some people with experience with both Mørch arms have told me they prefer the UP-4 for its greater liveliness. But regardless of how one votes on that, the fact that the issue is debatable shows how well the UP-4 is doing. It is, after all, much less expensive than the DP-6-and a fraction of the price. The bass of the UP-4 is also not quite up to the very highest standards in weight and extension, although, to tell the truth, the possibility of getting the mass right in the UP-4 will almost always completely swamp whatever theoretical advantages other arms might have in the bass. (Of course, the DP-6 also has adjustable mass. And other contemporary arms do tend to be more or less mass-compatible with most moving coil cartridges, but only pretty close; only adjustable mass will make exact matching possible.)
Incidentally, the UP-4 is as elegant looking as all get out, in a Danish, restrained but “high-tech” way–Plexiglas and chrome , and so on. It will certainly look at home in even the highest High End setup.
Now I have to admit that I have become convinced that the ultimate in vinyl playback requires damping at the front end of the pickup arm (the cartridge end), à la the systems used by Townshend, or Maplenoll for lateral tracking. But no doubt many people are not going to want to fool with the required trough. And even for those that will be willing to, the question remains of what arm to apply the front end damping to. The UP-4’s low structural resonance, adjustable mass, and low-friction, low-noise bearing make it a good candidate here, too.
In short, the UP-4 is a truly excellent value, offering a remarkable percentage of an ultimate performance at a fraction of the prices usually charged for would-be “best” arms. The vinyl world, what’s left of it, is waking up to unipivot arms, as well it should. The UP-4 has been around for a while in Europe, but its sound principles are by no means obsolete. Cool looks, fine sound, reasonable price; if money is any object, it’s a very attractive package indeed.