Fake Devices

Semiconductor Sourcing and Fake Devices

Vintage amplifiers incorporate a variety of different types and makes of semiconductor and often exact replacement types are no longer available. What we do in this case is to use more up-to-date devices with the same or superior specification. Direct replacement vintage audio power output transistors are particularly difficult to source. If our usual suppliers no longer stock an item, we source directly from main distributors in Europe and the USA.

Due to the huge world wide surplus of fake semiconductor devices currently circulating, we take great care to ensure the devices we use are full spec. This means that every batch we source are tested and physically examined* prior to acceptance and use.

Typical example of a fake power transistor. In this case a 2SB817 audio power output device. We obtained the fake device on purpose from a supplier on ebay. We could tell it was fake from the lettering and markings. The plastic casing has been removed to show the internal structure.

The one on the right is the genuine Sanyo 2SB817 with a die area five times greater than the fake device. Note, the copper heat pad on the Sanyo device is twice as thick too!

During DC testing, the fake device, mounted on a 2^oC/W heatsink, failed in less than 20 minutes with a c/e short while operating with a collector current of 2 amps and VCE of 10V.

Semiconductor Sourcing and Fake Devices

Copyright © 2009-11 Amplabs Last modified: September, 2011 15:23:31

Copyright © 2009-11 Amplabs
Last modified: September, 2011 15:23:31