Fidelity Designs LTD

Carbon fibre subchassis replacements.

Carbon fibre subchassis replacements can be produced for most suspended turntables. I keep the LP12 model in stock due to it being a popular turntable.

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Description of the new updated carbon fibre subchassis.

Posted on by Ben Lamb -

The lightest LP12 sub-chassis available at an amazing 258g These sub-chassis upgrades use a laminated closed cell hard foam construction. The core of the sub-chassis uses hard closed cell foam which is used for similar purposes in motorsport and aerospace. When laminated between multiple layers of carbon fiber cloth infused with epoxy resin it forms a very rigid light weight structure. Layers of carbon cloth are laminated onto each side.

The benefits of a light weight sub-chassis have been known for some time and have been used in some of the most notable suspended turntable designs. The lightweight sub-chassis allows the springs to respond to external vibration more rapidly and the low mass structure is limited in it's ability to store kinetic energy. This enables you to keep the mass where it belongs, in the gyroscopic action of the platter. Less weight overhanging into the arm-board support brings the sub-chassis closer to the ideal of a pure triangular design reducing the loading on the springs to maintain a balance. It all makes sense when you give it some thought !

In order to provide absolute rigidity and to follow the original specifications of most turntable sub-chassis, two carbon horizontal spines run the length of the inside of the sub-chassis. These spines are bonded to the top and bottom carbon skins. This further increases the performance of the sub-chassis by creating a rigid internal box section structure. The bearing mounting surface is machined to ensure the correct orientation of the main bearing in the turntable.The original pressed steel sub-chassis rings like a bell whilst the carbon fiber/foam design is inert. This means increased damping of motor vibrations and bearing noise from the platter. The replacement sub-chassis weighs one third of the original (258g vs 790g) allowing a greater proportion of the sprung mass to belong to the gyroscopic action of the platter. This enables your turntable suspension to be more responsive in doing its job of isolating the turntable from external vibration.

Includes a set of stainless fixings for the main bearing/earth wire and arm board.

Video of the old Carbon/Balsa version of the sub-chassis.

The standard cost for an LP12 subchassis and standard arm board mounting screw set is £139 plus postage costs. A custom sub-chassis made to your specification would need plans to detail exactly what you need or your original sub-chassis sent to me so I can build the replacement to the original dimensions. A deposit would have to be paid before I could start construction

In conclusion a sub-chassis upgrade is a cost effective way to bring aerospace engineering technology to your turntable in order to make it that bit more exclusive. Due to the radical difference in mass and materials used you increase the chances of making your turntable sound more neutral and uncoloured in comparison to other upgrades.