MarshallMarshall guitar amplifiers are among the most recognized in the world. They are known for their Marshall "crunch".
OptocouplersOptocouplers transfer electrical signals between isolated circuits through light, allowing isolation of high voltages from lower voltages.
Optocoupler - Vactec, VTL5C1, Vactrol, New Old Stock
New old stock Vactec VTL5C1 vactrols from Perkin Elmer Optoelectronics. These premium vactrols are a great choice for use in phasers, compressors, tremolos, and synth modules such as low-pass gates. They are also used in switching circuits in amplifiers. Limited quantities are available.