This is an internal picture of the Masterclass LA-4, Sugden Audio most popular Pre-amplifier. There are a number of features and nice touches on view that even owners might not be aware of. The circuit board has gold plated tracks with a solder resist coating. The flat grey cable seen clearly in the image, connects the input selector directly to the relay switching circuit, this keeps the signal path as short as possible from input to output.
The relays have gold plated contacts and are long lasting devices used in telecommunication and chosen for reliability. The balanced input uses a ‘virtual transformer’ and is true balanced. There are a total of twenty four high precision Silver Mica capacitors that are made for Sugden and to their specification. These are used throughout the LA-4 in all critical signal area for maximum performance.