Tonearm effective mass

Dear Badcap: Go up but the change in the effective mass will be small due that the counterweight is near the tonearm pivot.

If you need a significant change in the tonearm effective mass and if you can then you have to do it at the tonearm headshell position.

Regards and enjoy the music.
Raul.

Correction. If ALL you change is the counterweight (same cartridge, same mounting screws, etc.):
- a heavier c/w closer to the pivot REDUCES effective mass
- a lighter c/w farther from the pivot INCREASES effective mass

Effective mass is a function of mass X the SQUARE of the distance from the pivot, so changing the distance has a larger effect than a change in mass.

Aside from that, for practical purposes I agree with the rest of Raul's post.

Thanks I thought I had read a heavier counterweight with everthing else the same would lower the effective mass. So it would take a big increase in weight to make very much of a difference? I am trying to get the resonant frequency up to 10 from 8 with a fixed headshell.

Thanks

Doug: Thanks for that information. It is both counterintuitive and very relavant to me at this time as I am in the process of doing a tonearm upgrade and one of the goals is to increase effective mass of the tonearm (cartridge is a wood bodied Denon 103R). I am looking at changing out the stock headshell on the new tonearm (stock headshell weighs about 6-7 grams) with an aftermarket headshell that weighs 16 grams.

I've been assured by someone who owns the same tonearm that the stock counterweight on the arm will balance out the cartridge and heavier headshell. There is also an optional heavier counterweight available for the arm to balance out heavier cartridges. I'm assuming, though, from what you say, that the lighter (stock) counterweight in this situation is going to result in higher effective mass.

Would you concur with that? Thanks in advance.

Dear Doug: The question speaks to add weight to the counterweight, IMHO if you add weight at any position of the counterweight the effective mass goes up against the original one ( obviously with out change in the original counterweight position. ).
A plain answer to a plain question.

Regards and enjoy the music.
Raul.