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Spark suppression for your Lenco power switch

For a number of years we have been offering replacement spark suppression capacitors for Lenco turntables. These capacitors are effective at reducing arcing on the power switch, which can substantially shorten its life. In addition, this arcing can also create a loud ´pop´ from your speakers. While this X2 capacitor works, it is more of a cost effective solution, rather than the best solution.

A better solution to switch arcing is a RC suppression, or snubber, network. This employs a resistor and capacitor in series, and is more effective at dealing with inductive arcing which occurs during switch activation. The energy stored in the inductor, the motor in the case of the Lenco, will subject the switch contacts to a high voltage as the motors magnetic field collapses. This voltage will arc across the open contacts, much like a cars spark plug, until the gap is too large. The suppression network acts to absorb this energy and safely drain it from the circuit.

Over the past couple of months we have been testing a few different suppression networks, and we have finally found one which we think offers the best solution for a Lenco turntable. These suppression networks are readily available, but all the ones we found were designed for PCB mounting, and therefore had very short legs. This can be problematic for mounting to switches in solid plinths where access is through a long hole. To make mounting as easy, and suitable for the greatest variety of scenarios, we searched for a snubber with long leads instead of the standard PCB wire legs. We finally managed to source an RC suppression network with 5cm long insulated cable legs which employs a 120ohm resistor in series with a 0.1uF capacitor. This combination works extremely well with the Lenco motor for silent, arc-free shutdown.

The down side of this solution is the cost. RC suppression networks are more expensive than standard X2 capacitors, but as these will last many years before needing replacement, the cost over the life of the turntable is small. These RC snubber networks are now available to order our store.

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