What is the BLACK SABLE process in detail?
Vacuum tubes selected to go under the BLACK SABLE process are burned in under load on our burn-in racks for 24 hours. Not only are the filaments lit, B+ voltage is applied to the plate to simulate real world use. This burning in helps to finish cathode activation and reduce popping and static noise. These problems are normal for vacuum tubes and result from uneven cathode coatings or impurities. Our 24 hour long burn-in insures that the cathode is settled down and broken in. In addition to cathode activation, burning in allows the plates, grids and cathode to settle into the mica supports. This step alone serves to improve the sound and performance of the vacuum tube. The vacuum tubes are then placed into our proprietary Cryo-Processor where a computer controlled program slowly reduces the temperature from ambient / room temperature to -300 Fahrenheit / -184 Celsius. The tubes will then soak at this deep cryogenic temperature for 24 hours. During this time, the stresses that have built
