Hickok 533A Mutual Conductance Tube Tester. Reads transconductance (gm) directly in micromhos. Works, checked with: 5U4, 6AQ5, 6L6, 6SN7, and 12AX7. Tests 4, 5, 6, 7, 8, and 9 pin tubes for shorts, gas, and quality, including: 1L6, 2A3, 5AR4 (GZ34), 5V4, 6AS7, 6CA4, 6CA7 (EL34), 6BM8, 6BQ5, 6DJ8, 6EU7, 6FQ7, 6SN7, 12AT7, 12AU7, 12DW7 (7247), 10, 45, 50, 83, 6550, 7025, 7027, 7189, 7199, 8417, KT66, and KT88. Nice gold top, shows little wear from use. Although it has not been calibrated, it reads pretty close to the many Hickoks I have tested. Shown testing a known strong 6L6GC. Has top cap lead, tube roll chart, bound copy operating manual, and tube data supplements including obsolete and foreign tubes. Sold As Is. If you have no experience with electronic test equipment, and do not know what to expect from a tube tester, please do your research; ask questions before offerding. All items are insured for full value as shipping can be rough, despite being well packed. Full prompt refund minus original shipping if item is not as described, per policy. Thanks!

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