Question on Victor Needle Bar Replacements

[brianu]

I've purchased and made use of a few needle bar assembly replacements from Ron Sitko, for both Victor Exhibition and No. 2 reproducers. I've noticed with all of them that the depth of the hole in which the needle sits is much shallower than with the originals, leaving much more of the needle exposed. Is this ok? Is there a recommended length for the exposed portion of the needle, or does it not really matter?

[winsleydale]

Because the length of exposed needle changes the moment arm of the assembly (which is basically just a lever), it affects the volume. A shorter needle will give greater volume, as it is both stiffer as well as having more angular movement in order to track the groove than a longer needle. I believe this was the concept behind the Cheney Talking Machine's mode of volume control.

On the other hand, because a longer needle will have to move less from an angular standpoint in order to track the groove, it will thus experience less resistance from the tension springs, resulting in less wear to the record.

[JerryVan]

Because the length of exposed needle changes the moment arm of the assembly (which is basically just a lever), it affects the volume. A shorter needle will give greater volume, as it is both stiffer as well as having more angular movement in order to track the groove than a longer needle. I believe this was the concept behind the Cheney Talking Machine's mode of volume control.

On the other hand, because a longer needle will have to move less from an angular standpoint in order to track the groove, it will thus experience less resistance from the tension springs, resulting in less wear to the record.

"A shorter needle will give greater volume..." Not necessarily. In an ideal system, with no resistance to needle arm movement from the tension springs or the diaphragm, the excursion of the opposite end of the needle bar will be greater and theoretically produce more volume. However, since a shorter needle extension makes a shorter lever arm, and therefore a lesser moment, the ability to overcome the spring/diaphragm resistance will be less as well and quite possibly, so might the volume.

Agreed that a longer needle extension will produce less record wear.

There is most likely and ideal needle extension and also most likely, Victor determined what it should be. I would defer to their original design. (Of course it also depends on what brand of needle you using as I'm sure there is length variation from one brand to the next. Most probably Victor assumed/demanded that you used only their brand and designed the needle chuck as such.)