Installing cartr.:slide it all the way to front?

But if the cartridge can't be moved inside the shell, or it's a SPU type of cartridge, how can one get both the pivot-to-spindle distance and overhang right? Sometimes you have to move the whole tonearm, but that would be a violation to the rule that for each arm there is one optimal pivot-to-spindle distance.

But if the cartridge can't be moved inside the shell, or it's a SPU type of cartridge, how can one get both the pivot-to-spindle distance and overhang right?

You can't. Any parameter you cannot adjust forces you to rely on the accuracy of the manufacturer(s).

There are no high end cartridges with SPU mounts AFAIK. Plug and play rigs are for users not interested in optimizing the performance of their systems. That's a perfectly valid approach of course. Different strokes and all that.

There is one high end tonearm (SME) which does not allow adjustment of the cartridge in the headshell. SME does include a sliding base that adjusts overhang by changing the spindle-to-pivot distance. This still assumes a perfectly square cantilever, which is a bit optimistic IME. Some SME owners actually drill out their headshell mounting holes to give themselves some play.

Sometimes you have to move the whole tonearm, but that would be a violation to the rule that for each arm there is one optimal pivot-to-spindle distance.

There is no such rule. Where did you hear that?

First of all, double check the pivot to spindle distance of your arm. I've mounted a couple of dozen cartridges of all kinds in Rega arsm over the year without any problems, so its possible that your arm is incorrectly installed. If the arm is mounted in the right place and you still can't get the overhang correct, as a last resort you could lengthen the slots in the RB600's headshell using a small round jeweler's file. You can buy jeweler's files in hardware stores and hobby shops.

Hi Doug, I'm familiar with sound reproduction through vinyl, but was never interested in technical questions like how to install a tonearm correctly, but now I am! Why do tonearm manufacturers specify a pivot-to-spindle distance for each arm they produce? If there is no such rule as: for each arm there is an optimal pivot-to-spindle distance (to minimize the lateral tracking error), then you can place the arm anywhere you like. So, if you have to move the tonearm to get the overhang right, another pivot-to-spindle distance would be the result. This is the compromise with a non lineair tracking arm. One has to choose for: exact alignment of the overhang or not to deviate from the specified pivot-to-spindle distance, if the cartridge is fixed within the head shell or if a SPU is used. Please correct me if I'm wrong.

Doug: I think that SME don't change the spindle-too-pivot distance. They " move the arm " but mantain fixed that distance. Maybe I can't explain it: they mantain the geometry relationship between the overhang number and the spindle to pivot distance.

Regards and enjoy the music.
Raul.