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How to select a good set of vacuum tubes

  Our company has been engaged in the design, development and sales of electronic tubes for more than 15 years. In the long-term practical experience, we have formed a unique electronic tube screening process.

  Our vacuum tube screening is divided into four steps:

  • First, the appearance of screening

  1. The glass bulb is clean, transparent and crack-free
  2. The core column is vertical, no shaking when shaking, no abnormal sound
  3. The glass bulb is well integrated with the tube base, no looseness
  4. the pins are smooth and not loose
  5. The tube’s diameter and height of the paired tubes are basically the same
  • Second, vacuum tube stability screening

GV Match result
 Our company has professional testing equipment imported from the United States, which can be quickly tested for products with unstable electrical performance. For the unstable products, our company will carry out the second burn-in, if it is still unstable after the second burn-in, our company will return to the factory as a non-conforming product.

  • Third, vacuum tube plate current screening:

 After the vacuum tube is completed, it cannot be repaired. In order to improve the product’s pass rate and economic benefits, the manufacturer’s plate current range is relatively loose. Take the ordinary KT88 as an example,under the manufacturer’s test standard, the allowable plate current range of the manufacturer is 20-70mA. In order to obtain a vacuum tube with a strong launching capability and a longer service life, we will place orders above the standard price for select a product with a plate current ranging from 35 to 60mA.

  • Fourth, pairing screening

 The tubes that entered the pairing process have passed the screening of the previous three steps. Our tube matching is divided into two levels:

FQ level: plate current pairing, the pairing standard is consistent with the factory. (We use this kind of matching method by default)

PQ level: plate current + transconductance pairing, paired product plate current error Ia < 5%, transconductance GM < 5%. This level of matching products needs to be booked in advance and an additional handling fee will be charged usd 5.0 / pc.