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Adding mass to a tonearm

I would like someone to explain to me why adding headshell weights doesn't really alter the mass of the tonearm that much when figuring cart vs tonearm compliance. I have a Denon DL-103r and I keep reading that's it's for high mass tonearms. I also hear that adding headshell weights doesn't really alter the mass. What gives?

I want to try a DIY on my Pioneer PL-530 turntable tonearm where I mask off the arm such that only the chrome arm on the headshell side is visible and spray it with Plastidip. This would seem to add mass and resonance control. If it doesn't work the I can just peel it off.  
last_lemming
yogiboy's avatar
yogiboy
5,613 posts
 
If you add a headshell weight to the tonearm it will change the resonance frequency of the tonearm and cartridge.
bdp24's avatar
bdp24
9,697 posts
 
Adding weights to the headshell DOES increase the effective mass of the arm. Not just because of the weight itself, but also because to then balance the arm, the counterweight on the back end will need to be moved further from the arm's pivot, which also increases the arms effective moving mass.
randy-11
1,913 posts
 
it doesn't really alter the mass of the tonearm that much because of the pivot
nandric's avatar
nandric
4,086 posts
 

Agree with bdp 24. Probably contra-intuitive but moving the

counterweight nearer to the pivot decreses the arm mass.

Adding weight to the headshell on the other side ''obviously''

increases the arm mass.

sbank's avatar
sbank
3,378 posts
 
Even if you proceed with your experiment, you might just find that you don't have enough counterweight on the back of the arm. Headshell weights are usually for use with extremely light cartridges, but that isn't the case with 103R. 

I'd suggest trying the resonance test tracks on the HIFi News test record before and after any experiment. 

Also, a potential can of worms, but if you are planning this whole concept because of vinylengine calculator results "are you factoring in  the tendency for Asian, espec. Japanese, carts to establish their µm/mN compliance figure at 100Hz rather than the 10Hz typically used by the various on-line calcuators and formulas. Unfortunately many Asian manufacturers rarely publish that info. Euro carts generally use 10Hz.

I also understand, but am not an expert here, that there is no direct translation or conversion formula. The general rule I've read is to multiple the 100Hz compliance number by somewhere between 1.5 and 2.0, then use that result as part of the resonance frequency assessment. I use 1.75. Vinyl Engine gives the green light to resonance frequencies in the 8Hz to 11Hz range.". Cheers,
Spencer
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