Hi Aigenga,
They're not listing effective mass. It looks like it's the weight of the armtube w/o the headshell. I don't think it's possible for the eff mass to be less than headshell weight.
Normally, you can reduce the eff mass of an arm with a 12g shell by substituting a lighter shell. A high percentage of the difference in weight will subtract from the eff mass. So if you use a 7g shell you'll reduce eff mass by almost 5g.
One ray of hope - listed mass is lighter than the 9" version and it looks like this is due to the aluminum collet? Normally a longer armtube of the same design will be heavier. If this is the case, the collet is directly behind the shell and that is the second best location for reducing eff mass.
Another good thing is the fluid damping. This will reduce the amplitude peak of the resonance. Use sparingly though, it can also affect transient response and you'll probably have to experiment.
The easy(?) way to figure the mass is with a test record and cart(s) of known compliance. This might be easier if the damper is dry. With the low frequency tones you'll see the cart vibrate at resonant frequency. Take the info to VE tools in database. Just solve for eff mass. You need the cart and fastener weight.
When these arms first came out the Brit importer said the eff mass of the 750E was 20g. I don't know if this is right, but it seems more realistic. People reported using the OC9II successfully with it. I think the cart cu is the same. Maybe a weight difference? BTW, AT 10cu @100Hz = 18cu @ 10Hz.
With the fluid damper I suspect you'll be fine, but I have no experience with the arm.
Regards,
They're not listing effective mass. It looks like it's the weight of the armtube w/o the headshell. I don't think it's possible for the eff mass to be less than headshell weight.
Normally, you can reduce the eff mass of an arm with a 12g shell by substituting a lighter shell. A high percentage of the difference in weight will subtract from the eff mass. So if you use a 7g shell you'll reduce eff mass by almost 5g.
One ray of hope - listed mass is lighter than the 9" version and it looks like this is due to the aluminum collet? Normally a longer armtube of the same design will be heavier. If this is the case, the collet is directly behind the shell and that is the second best location for reducing eff mass.
Another good thing is the fluid damping. This will reduce the amplitude peak of the resonance. Use sparingly though, it can also affect transient response and you'll probably have to experiment.
The easy(?) way to figure the mass is with a test record and cart(s) of known compliance. This might be easier if the damper is dry. With the low frequency tones you'll see the cart vibrate at resonant frequency. Take the info to VE tools in database. Just solve for eff mass. You need the cart and fastener weight.
When these arms first came out the Brit importer said the eff mass of the 750E was 20g. I don't know if this is right, but it seems more realistic. People reported using the OC9II successfully with it. I think the cart cu is the same. Maybe a weight difference? BTW, AT 10cu @100Hz = 18cu @ 10Hz.
With the fluid damper I suspect you'll be fine, but I have no experience with the arm.
Regards,