Dear Nrenter:
>You do not know what you do not know, until you know what you do not know, and only then can you make a guess if it really matters. :)
As a designer-engineer, one needs to be able to come up with a steady stream of new thinking and new technology. What is harder is to know in advance what will make a big contribution to the sound, as opposed to parading new technology for new technology's sake. The answer is to have lots of ideas and filter out the mediocre ones at the prototype phase. Not particularly efficient, but it works.
>Do you believe the primary role of VTF is to align the coils & iron core within the gap, or to facilitate sufficient stylus / groove contact for proper tracking?
Both. The importance of VTF in maintaining sufficient stylus-to-groove contact for good tracking cannot be downplayed. But it is also true that VTF _can_ be an important tool in aligning the coils to the magnetic circuit. OTOH, with a conventional symmetrical damper system and body structure, it simply isn't possible to get the coils aligned to the magnetic circuit with VTF applied (as should be clear if you study my pdf on the audionord website). Even applying a little VTF introduces an angular alignment error, and the higher the VTF, the worse the error becomes. Either the cantilever mount needs a mechanically pre-biased suspension and damper system (like the Delos) so that applying VTF will bring the coils into alignment with the magnetic circuit, or the body structure needs a special design so that the magnetic circuit can have a different angle from that of the cantilever mount.
>I'd assume your dampener materials / suspension design / stylus geometry were selected to optimize tracking at the precise load to align the coils & iron core within the gap?
Absolutely. The damper shape and compound, suspension alloy, diameter and length, and stylus angle were all selected so that proper tracking would be achieved at the same VTF as required to make the coils aligned with the magnetic circuit. However, also note that damper hardness and therefore angular deflection will change depending on ambient temperature (this is true of most cartridges). If the temperature drops you will need to increase the VTF to keep the coil angle aligned with the magnetic circuit, and if the temperature increases you will need to decrease the VTF to achieve the same. I normally recommend for the user to keep a small incandescent lamp and thermometer in the vicinity of the tonearm, and use that to control temperature as well as maintain good visibility. Target temperature should be 23~23 degree centigrade.
>And given your narrow range of VTF (and subsequent VTA) to align the coils & iron core within the gap, did you take this opportunity to help users ensure a proper SRA during setup (i.e. if VTF is within tolerance, and, for example, the head shell is parallel to the platter under load, VTA - and therefore SRA - will be optimized)? Given your necessary design tolerances, I'd think this would be plausible.
Yes, you have it right. All parts in the cantilever assembly were designed and all tolerances specified with this goal in mind. If the tonearm bearing height is positioned so that the application of the recommended VTF aligns the tonearm pipe so that it is parallel with the LP surface, the cantilever of the Delos should assume a 20-degree angle to the LP and be perpendicular to the red piece that carries the front magnet, and the stylus should have a 1-degree (+/- 1 degrees) rake angle to the LP. At least whenever I have set up the Delos with proper tonearm bearing height and proper VTF, all of the other angles including VTA and SRA have more or less fallen into place.
The Delos incorporates another unique but IMO sensible feature which is intended to facilitate proper cartridge alignment in the tonearm headshell, the body structure makes greater use of non-parallel surfaces to better control resonances without relying on excessive damping which could rob the sound of dynamics and immediacy, the instruction manual discusses in-depth what cartridge loading does and how to achieve suitable loading, even the packaging box was designed to be more interesting to look at than normal. It will be fun to hear what Delos users think about all of this.
>Thank you for indulging my questions!
No problem. As you can probably guess, working on the Delos has been a fun and educational experience, and I hope that some of that spirit is reflected in how it sounds and what it is like to use.
cheers!
