A couple of years ago, I bought a prototype Odyssey arm as part of a bigger deal.
At some point in the past the original arm wand had become corroded, it was probably made in the early 80's, if not before. The previous owner, took the arm apart, rebuilt it with new bearings and made a new wand using a blue arrow shaft. A very good idea, and a nice piece of lateral thinking, but unfortunately, the wand is way too light, not enough effective mass. He then put the arm on the shelf and forgot about it.
I got the arm as part of a deal, the previous owner didn't want to see it go to waste.
A little later I bought a 401 and thought the two would make a good match.
But the 401 looked scrappy in bit of IKEA worktop. So I saved up and bought a Slatedeck that could hold up to a 12" arm.
To this I added a Slatedeck long-universal arm mount, this is an improvement over the existing arm base allowing better VTA setting and support for longer arms etc.
But the arm is still not right, I have tried adding mass, but the tube is so very lightweight to start with.
Next, I took the arm to j7 of AudioOrigami to see what could be done about the wand. He agreed to make a new wand, for a reasonable price, but being an awkward sole I thought, if I'm going/gone to all this expensive to resurrect this little beauty then why not do a 12" arm.
j7 confirmed my thoughts on the low effective mass and suggested I do some maths to work out what I want in terms of mass and geometry. He also asked for a scaled drawing to work from - I know I would.
So its time to get my maths dusted down, first up, the geometry.
Attached is a gif of a sketch of the geometry I would like j7 to make for me. I hope to eventually turn this into an scaled drawing for the wand, the Slatedeck base and the pillar from the arm will be reused.
Can anyone cast a critical eye on this to see if I have the correct starting point. I would like a 300m effective length and used the Loefgren "B" calculations from the BaerwaldLofgren spreadsheet to get the drawing attached.