I really do not like using metal switches for HiFi. Electric currents (including small signals) produce magnetic fields in surrounding metalwork. Even aluminium produces some bizzare effects when a magnetic field is introduced to it – look into this on YouTube, it’s very entertaining and quite surprising. These fields then reflect electric currents back into the original source, the phenomenon is known as ‘back electromotive force’ (Back EMF) and is well known. For this reason I will be using plastic switches for the Liquiphonics amplifier.
The switches I have been using now for so long I can’t remember when I didn’t are from Lorlin. I am sure I was introduced to these switches when I worked in the R&D lab at Kelvin Hughes in Hainault and that seems a very long time ago. They are about as all plastic as they come and use silver plating on the contacts which is perfect for me. The input switching and the switched attenuators for the volume controls will use Lorlin’s waterproof CKS series, 2 pole 6 way switch:
Both the amp gain and output switching (between speakers and headphones) will use their RMS1153:The first can be found both at Farnell and RS Components but these suppliers only stock the single pole, single throw version of the later listed above. They do not stock the double pole version. Fortunately Lorlin have been very helpful and sent me two free-of-charge samples of that switch.
Plastic switches will never have the action of a well designed metal switch (the stresses of the indexing mechanism can be much higher in metal) but considering these are plastic the feel is very good indeed. Plus I have never had one of their switches fail on me even after years of use.
Many thanks for your support Lorlin, much appreciated.