Replacement of the vacuum tubes
Similar to a light bulb, vacuum tubes have a certain life cycle and have to be replaced after a period of time. We guarantee the product for 12 months after purchase or 2000 hours of usage. However, most of our vacuum tubes live much longer. When the tubes are new, the ampere meter will show 80 milliampere.
When it displays less than 60, it's about time to order new ones.