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RonyWeissman wrote:

…Have you tried….

Romy the Cat wrote:

…. in the field of cartridges dissectomy….

Paul S wrote:

..And I coulda sworn I'd just cleaned 'em...Paul S

I spend so time figure out what is going on with my Shelter. I was not able to found how to open the cartridge safely. The bottom of the Shelter has a plastic tubing, sort of cover that protects the coil, I cut the plastic cover off and the needle sustention and the coil was exposed. Looking under a scope the damping looked fine and elastic but I realized that there a tone of dirt between the magnet and the coil. I mean the dust accumulated there and built a bridge between the movable coil and magnet. Too much for hard guess why the cartridge sounded so purely.

I cleared the gap with soft brash; it looks like there were no metal particles in there. After I did it I detected that I pulled one of the wires from the vertical coil that crossed the gap to magnet. I put is back. I put the cartridge back to the tonearm and… it played wonderfully.  No problem with compression, perfect ability to play soft and so on…. It looks like the problem is resolved. Well, yes and no…

I plagued a few more records and I hear some bass character that I would attribute to too low VTA or too low loading impedance value. The VTA and the loading were of course fine. I took the cartridge off and begin to explore what is going on. OK, I took it off 20-30 times (that to SME detachable shelf), making minor adjustment and truing to fine what the bass over damping was coming from. The cartridge has two crossed coils and very fine (I think 54ga) wires going the pins. What I learned that the profile of those wires and the level of freedom with which they live the coils and run away from coils does affect the damping of cartridge could. Sort of the wires act as the additional coil suspenders… Playing with it I found a configuration what the bass was more or less clean but I am not comfortable that there is so much flexibility in this. I am still not convinced that the coil’s wires in my cartridge do minimal impact to the coil’s movement. I guess do not know the reality - is blessing…

There was another, even worse aspect that I discovered. After a record or two playing and expecting the cartridge I was seeing each second time as the new dust come to the gap between the coil and magnet. Without the protective plastic cover the cartridge acted as a vacuum cleaner socking in all dust. Very very ugly! I have written yesterday ay another forum:

“The quietness of cartridge is very complicated subject and it is not always a good thing. If fact, for one of my arms do prefer to have a very hard-reading cartridge instead of forgiving one. In the certain pressings and on certain labels a hard-reading cartridge (uselessly the cartridges of “complex profiles) is as quiet as conical cartridge but they have an eddied value to scarp out the grove the last cent of “crisp”.  The 901 might not used for quietness assessment because it is ridiculously hard-reading cartridge. In addition to unfriendly for grove’s dust and grove’s wearing needle the 901 has (at list in my setup) the profile of the tip that is VERY electrostatically unfriendly. While the needle scraps the record it generates a huge electrostatic field, immeasurably higher then other cartridges I used. If you have high gain phonostage and high sensitivity speakers then juts by lifting the 901 a few mm above the record you can hear how the nearby groves are trying to discharge them to the 901 tip. I have no idea what in 901 responsible for it but something does. That all makes the 901 to have a very high (in fact insulting) level of surface noise. “

So, I need to figure out what happen electrostatically with Shelter and even if I put a new cover on it looks like the cartridge will sock dust juts around the cover. I do not mind to play it nude and wide open (as so other cartridges) but with this electrostatic aggressiveness it would not work out. The alterative would be to go arrays from the Shelter’s electrostatic behave all together. I wonder of it is the Shelter of something else… I have expected the tonearm and TT and I did not detect anything unusual or alarming…

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