1. From the printed fonts: the authentic fonts are well-proportioned and the writing is not easy to be wiped off, and the fake fonts are like the ones written on it. The gentle rubbing with the fingernails will make the writing color lighter or even the paint. clear.
2. From the branding of the package press: English letters and numbers are printed on both sides of the solid screw hole near the upper part of the tube, and the words of different manufacturers or countries are printed in the middle of the lower part near the pin, such as SK (three Ken), PHILIPPINES (Philippines), MALAYSIA (Malaysia), etc. The fakes are not printed, or the prints on the above two points are ugly and ugly, and the following points are not printed because of the word position. Of course, some of the joint ventures have no prints here, but there are no obvious differences between them and the original tubes.
3. From the perspective of the packaging and processing technology of the power amplifier tube: the boundary between the heat sink and the package plastic of the genuine product is clear and the corner is flat, and the boundary of the bond of the fake product is unclear or even has a gap (the market is the most The easy-to-see fakes are the small Toshiba tubes A1491/C5198, D817/D1047), and the surface has a rough feel like brushed (this is the place where the fakes are most likely to be stuffed). Some models of imported tubes have been subjected to a matte finish on the surface of the fins (such as MATALOLA's MJL1302A/MJL3281A), while counterfeit and individual joint venture tubes do not have this process.
4. From the measurement results: when using the pointer multimeter R × 10k to block the positive and negative resistance between the c and e poles of the tube, the pointer of the genuine one is not moving or the angle of the swing is very small, and the fake The c and e pole forward resistance (NPN forward is Rce, PNP forward is Rec), the swing angle is much larger, that is, the resistance value is smaller (this indicates that the tube has a large penetration current); and the digital multimeter is used. When measuring the magnification of the tube β, the consistency of the genuine (especially the inlet tube) is very good, and the consistency of the fake is generally poor.
5. Performance when using fake machine: Since the pressure resistance of the pipe is generally low, it is easy to cause the pipe to burn when it is turned on; or the heat is more serious than the genuine one. At this time, the c and e pole resistance of the pipe is smaller than when it is not installed. Much more, and the deviation of β is even larger, and there is no such phenomenon in genuine products.
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