The effective mass of the Technics arm with stock headshell weighs 12g. That headshell weighs 7.5g, which means the effective mass of the rest of the arm is 4.5g. I was under the impression that the Sumiko HS-12 weighs around 11 or 12 g (but I could be wrong). If I'm right, however, it would add 4g to the effective mass over the stock headshell.
I use mine with a Denon DL-160 which weighs 4.8g, probably around 5.3g with mounting hardware. I've been able to use my Technics arm without the auxiliary counterweight, but just barely. I've since decided to add the other counterweight to get the main counterweight closer to the fulcrum, and overall I like it just a little bit better that way.
I use mine with a Denon DL-160 which weighs 4.8g, probably around 5.3g with mounting hardware. I've been able to use my Technics arm without the auxiliary counterweight, but just barely. I've since decided to add the other counterweight to get the main counterweight closer to the fulcrum, and overall I like it just a little bit better that way.