Our prototype number 1 is fitted with a thin-walled (0.2mm) aluminium armtube 9.7mm in diameter. It was factory hard anodized. For all previous and subsequent measurements we are using an Audio Technica AT7V
cartridge. It has reasonably low compliance and thus generates more vibration than most other moving magnet-type cartridged. It is also quite pleasant to listen to, making subjective evaluation a bit easier.