The deck has a modern DC motor, with speed controller card, and hall sensors; dead locked to speed for a solid month of continual rotation. I also completely redesigned the driveline, to that of a single idler wheel (it had three to begin with). This is a hot-rod of a deck.
There is a build thread overview, here, at audiohaven.org
. If you decide to join up over there, tell them that mfrench
sent you (please and thanks. there is a new membership signup contest underway).
This is the c.weight end:
The c.weights pivot on an axle that is perpindicular to the arm wand. They freely pivot. When they encounter a warp, they drop straight down, rather than having the weight firmly attached, and being made to carry that load thru an arc. I spoke with Frank Schroeder about my concept, and he agreed. He suggested that the fixed counterweight makes the arm plow thru the warp, causing wear in the groove, whereas, the rotating c.weights tend to unload at the hop of the warp, then reload on the downslope, rather than to have to carry the load the the arc; comparing it to a steamer/high seas cutter plowing thru waves, without wavering (which is not necessarily good for record wear).
They also act as stabilizing outriggers.
The bead chain is to damp out the side-to-side rocking action that unipivots have. You can see them quickly and quietly bring the arm back to still and stable. Its akin to a phase cancellation.
The wires are lashed to the arm wand with waxed dental floss.
The arm cost -$1.50, and is made from free garage junk,, fishing weights, copper plumbing pipe, and precision brass hobby tubing.
Unipivot stanchion, and the RatTrap arm holder:
It allows for VTA adjustment:
Brass and soapstone articulating mount:
Lots of room for adjustments.