Durand Tonearms Balancing nature and technology






The making of the Talea™

The arm base
In order to achie
ve the sound quality and the ease of use that I am looking for, some of the parts making up the Talea™ are  very complex. The most involved part to machine is probably the "lower arm plate."
It is in many ways the "heart" of the Talea™. It serves as support for the pivot, the azimuth tower, the anti-skating mechanism, the arm lift and the arm rest, and it rests on the VTA column, transmitting vibrations coming from the arm wand into the turntable. Some of its construction involves machining tolerance of .0005" (12 µm), so that the part  achieves ideal mating with the others. On a 2-axis mill, its fabrication takes about 7 hours. Fortunately, there are more elaborate mills that can make it in much shorter times--although their programming is quite involved (and they cost a fortune!). Different materials were evaluated in order to find the one that yielded the best sound for this critical part, as well as all others involved in the construction of the Talea™.

Talea_Lowerarmplates 1small
Lower arm plates fresh off the mill

The Talea™ armwand

The material used for the armwand is of course just as important as those used for every aspect of the assembly. The experiments conducted to determine which material for this part would deliver the best sound were not conducted in isolation: they had to be done with the armwand mounted on the base because all the elements of the Talea™ work in concert.

Talea15armwandcroppedsmall
(photo Michael Cole © 2010)

While the 1st generation Talea™ used the exotic hardwood Jatoba, it was found that, given the changes in other materials, another exotic hardwood, the Bolivian Rosewood now gave superior results. As before, the shape of the armwand was derived from careful analysis of the shape of the violin bow. Its cross section, in particular, is designed to allow the ideal combination of flexibility and rigidity for this application.


After the "raw" armwand is received from our woodworker, it first undergoes an 11-step process of sanding. It is then measured and weighed  for archival purpose, the other parts of its assembly are added, and it is  tested for mechanical balance.
If all is well so far, it is wired and tested  for sound: this is the "tuning," where final adjustments in shape can be made if necessary. Once the results are satisfactory, the armwand then undergoes a staining  process similar to the one that has been used by bow makers for centuries. It is let to dry and  finally goes back on the turntable, where it is played for several days.

The Talea™ headshell

The cartridge is first mounted on a cartridge plate, which is in turn fastened onto the headshell with a bolt. The bolt is also engaged in a slot cut in the cartridge plate, a system that allows the user to easily set the effective length by sliding the cartridge plate along the slot.

If the user likes to change cartridges often, it might be worth having more than one cartridge plate. One can simply leave the cartridges fastened on their respective plate, simplifying the process of mounting them on and off on the armwand (alignment will still be needed for each cartridge, though!).

Talea16cartridgeplatecroppedsmall
(photo Michael Cole © 2010)

Setting the pivot-spindle distance

The pivot-to-spindle distance is one of the critical parameters to achieve proper geometry of a tonearm. It is mathematically derived from the effective length (click this link to find a download of the spreadsheet from John Elison that does all the calculations for the Löfgren A and B geometries). If the pivot-spindle distance isn't set correctly, aligning the stylus on a protractor will result in a defective alignment, because the pivot-spindle distance and the effective length will be in the wrong relation.

Usually, this distance is measured with a ruler; that is sometimes a very difficult proposition, specially with tonearms that have no specific markings for the pivot location. With the Talea™, you don't need a ruler. A convenient and very simple tool is provided with the tonearm: the pivot-spindle jig.

Talea_P2S_jig_1

Talea_P2S_jig_2

The images explain the procedure. Simply engage the larger hole of the pivot-spindle jig into the spindle of the turntable. Then rotate the base of the tonearm (or move the armboard, on those turntables that have moveable armboards), until the pivot shaft is engaged in the smaller hole of the jig. When it is, the correct pivot-spindle distance is set!
For further reading on the subject of alignment, you can find a number of excellent references on the subject in our
Support/Links  section.