I’m trying to make a mission 774 into a 12 inch tonearm and have found a wand for one. I’m a little intimidated by creating a counterweight for it and was wondering if anyone would have any ideas on how to proceed. Is there an equation I have to follow to come up with the ideal counterweight? This is foreign territory to me, so any help would be appreciated.
Can you make a counterweight to turn a 9 inch tonearm into a 12 inch?
- Thread starter Bnoyes12
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was the original weight made of aluminum or steel? if aluminum, you may want to go to steel, or if steel, you may want to go to tungsten. you could go with a bigger weight of the same material, but that is less advantageous from a rotational stability standpoint. i'd bet you'll be able to find something off the shelf that can either fit perfectly as-is or with some thin sleeve between the weight and the stub.
The original counterweight is a sorbothane decoupled counterweight made of aluminum I think.
Weigh the 9" arm. Weigh the 12" arm. I'll bet the counterweight needs the difference added to it. A slightly heavier material would add the weight w/o making the counterweight longer. Adding to the outside diameter with the same material should have the same effect pretty much.
After mounting the longer arm wand....I'd be tempted to find a medium weight cartridge and mount it. Then adjust your current counterweight to the midway adjustment point. Then add clay to the current counterweight till the arm balanced out. Weigh the clay , add that to the weight to the current counterweight, and you'll know how much your new counterweight will need to weigh
tabarddn51
Super Member
Just Add two daubs of Blue-tac to the bottom sides of the C/W. to increase it's mass.
Cheers
Cheers
Thunderbox
Super Member
You would have to remount the whole arm. The distance from pivot to spindle needs to be different for a 12" arm than a 9" arm