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
emil, 
I had exactly the same problem with them, cure was worst than the disease !
look on ebay

plenty of headshell weights, screws etc etc 

cheap and easy to experiment
Some audiophiles claim to not care for the sound of lead, but if you're not one of them, small lead weights can be found at hobby and fishing supply stores. The ones at hobby stores can be had with self-stick tape on one side, for attaching to a headshell and/or counterweight. They are made for model train and slot car enthusiasts. Steel weights of various mass can be found at auto supply retailers---they are for balancing wheels, and also have sticky tape on one side.
I have three turntables and several Denon 103's.  That cartridge works will in my low mass  Grace 747, my SME 3009 improved, and my SME 3012 series one..  

As as long as you have enough counter weight I can't see you ever having a problem.  My favorite arm is the Grace and I use a variety of cartridges, both low and high compliance without any issues.  

Pioneer made a fairly respectable arm.  If you don't have enough tonearm counter weight you can add lead weight tape to the tonearm counter weight pretty easy and it's removable.

Using the counter weight tape also shouldn't effect the sound of the tone arm.  Again, the Denon is fairly forgiving.  Unlike a Decca, which demands high mass to sound right..