Mofimadness: 90% of the year I am deep in design and development, so I don't check email so frequently. Nonetheless, I don't see any of your emails (or cannot find them). No idea why. Overactive spam filters on my side? Something else?
The following is all checklist stuff that I am sure that you are aware of, but just to repeat it yet again, note that most tonearms change VTF depending on the vertical relationship between the stylus and the tonearm pivot. So be sure that the meter's weighing surface is placed at the exact height of the LP.
Also, some tonearms allow the tracking force to change over time, due to slipping counterweights or whatever reason. It is a good idea to periodically check the tracking force, at the LP height.
Also, be sure that your tonearm is very gentle when it lowers the cartridge onto the LP. If a tonearm with an undamped elevator mechanism "drops" the cartridge onto your LPs, each time that this occurs, it can stretch the suspension wire and compress the dampers beyond what they were designed for. This can quickly lead to low-riders, and can also reduce the lifespan of the cartridge.
Nonetheless, if your Delos suspension has collapsed and it is still relatively new, we will handle it as a warranty issue. We have publically said this before, and it is our normal policy.
As always with warranty issues, we ask that you send the cartridge back to us through the dealer that you purchased it from. Since we are totally and seemingly permanently overworked, it will take us some time to get to it, see what is wrong with it and get it fixed, but we will do it.
Bifwynne: Stylus wear is always affected by the cleanliness of the LPs being played, but if you clean your LPs with a suction cleaner or ultrasonic machine, the microridge stylus of the Delos should easily last 2500 hours. Stylus wear is also affected by how clean you keep the stylus, and clean LPs combined with an always-clean stylus should get you up to around 3000.
Total cartridge life is also affected by other factors such as how well-damped the tonearm elevator mechanism is,
Some users can get more than 3000 hours, but they tend to use tonearms with gentle elevators, very few contaminents in the air, and no sunlight or ultraviolet hitting the audio system, which is not so common, I think.
FWIW, the microridge stylus used in the Delos has been designed specifically so that changes in shape as it wears are minimal. The playing surfaces have a side radius of 2.5 micrometers, and are located on a protruding ridge which has parallel surfaces only 5 micrometers apart. This narrow, confined structure imposes a limit on how large the radius can increase to, as the stylus wears.
In marked contrast, nearly every other stylus shape has a larger side radius to begin with, and the playing surfaces are located on a triangular structure (as seen from directly above or below). You can see one such example at the following link, in a post by DaleH, showing photos of a Fritz Gyger S stylus.
http://www.vinylengine.com/turntable_forum/viewtopic.php?f=19&t=22894&start=252
The angles of the triangular structure are fairly large, and this allows the playing radius to increase steadily as the stylus wears. What this also means is that resolution dwindles steadily over the stylus lifespan. The OCL falls into the same basic category, AFAIK.
As a separate observation, we frequently get back cartridges that have enough dirt built-up around the coil area to impair optimal movement, yet otherwise the stylus and suspension are fine. With these cartridge we usually clean them up and return them at no charge, (unless there is a need to change components).
Our general experience has been that most low-riders can be cured by readjusting the suspension, and again, if this can be accomplished without any component replacements, we usually do this for free (or at a very minimal fee), even if the cartridge is outside of its warranty period.
When the stylus and/or suspension is actually worn out (which is usually 3 years of use when the cartridge is played a few hours each and every day), we do replace the cartridge with a completely new one. This is because the suspension wire and dampers will degrade with time and should be replaced to bring them back to as-new condition, also because replacing the cartridge allows us to build in any improvements that we have made to the cartridge design. This could be a different coil material, different suspension, different output pins, even a different stylus (these are all actual instances of internal components that we have improved as running changes in cartridge production).
FWIW, I corresponded with a fellow who was using one of our previous-generation cartridges, which was retipped by Soundsmith. As I recall, it was a Helikon or Argo, bought with a broken cantilever. Since he liked the sonic results, he then got a Delos. The Delos was purchased new, and he is using it unmodified. His subsequent correspondance suggests that he is clearly happier with the stock Delos than he was with the Soundsmith-retipped Helikon / Argo.
hth, jonathan carr