Elma Solves Amp Manufacturer’s Need for Custom Audio Switch

Mon, 06/06/2011 - 9:13am
Justin Moll, Elma (

Justin MollA well-known and highly respected manufacturer of audio and video products came to Elma with a requirement for a customized switch for a high-end tube amp.  Of course, the amp’s dials needed to have a great feel and last a long time.   Therefore, the precision audio switches used needed to have very low play.  In other words, a slight turn of the switch should produce an immediate effect.  In less precise switches, you can begin to turn the dial and the contacts won’t “catch” immediately, making it more difficult to do fine tuning.   Another requirement of the customer was for the switch to be rugged.  Even high-end amps get hit or dinged by accident.        


Elma designed a solution for the customer based on the Type 33 rotary switch.  The switch needed to be customized to a non-push-button style and a couple of other minor changes.  For extra ruggedization, Elma incorporated a stainless steel shaft.  The switch also had to be designed to fit the amp’s current knob design.   Elma was able to do this customization even in small volumes.   While one of Elma’s competitor’s switches was available with a rotational life of 35K to 50K cycles, Elma’s Type 33 was designed to perform 1 million cycles.   This is achieved via Elma’s superior design techniques that minimize wear on the switches’ contacts and using high-quality components.   Elma’s premium switches use gold contacts, a nickel-plated body, and metal shafts.  


The stainless steel shaft for the switch design was precision machined.  The result is the shaft fits perfectly into the switch body and doesn’t wobble.  This also reduced the “play” of the switch.   The Elma Type 33 also provided excellent tactile feedback for smooth audio controls.  Users can count the positions the switch turns without having to look at the dial indicators.       

Elma was able to provide a low-volume custom switch that had the precision, reliability, and long-life that meets the superior quality expectations of a high-end amplifier manufacturer.   To learn more about Elma’s switches, visit


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