Matched Pair GE 12AX7 / ECC83. HORSESHOE Getters with FOIL STRIP. AUDIO VACUUM TUBES. AMPLIFIER TYPE TUBES. Mini Tubes. TESTED on HICKOK TV-7.
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THIS TUBE 6AB4 IS THE EQUIVALENT OF 1/2 OR ONE TRIODE OF A 12AT7. I have a B&K 747 tube tester. This is a mutual conductance tester. I also use a Tektronix curve tracer for testing triodes. I give a number of evaluations for tubes.
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I test all tubes thoroughly and with great care. I test to the best of my ability, and I report all results honestly.
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Two of the four United States Air Force 12AT7WA , ECC81, E81CC Made in the USA πΊπΈ in 1958 & 1959 (This Particular Batch) which have triple mica & Horseshoe Getter's are for the Listed Price. Both are NOS/NIB Platinum Matched Tubes, Tested on Sencore TC -142 Mighty Mite V ~ no shorts β‘ no grid leakage π§ and the heaters π₯ are good π to go & Emissions test Perfect πͺ
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ONE NOS GE 12AT7WCTUBE. GE DATE CODE, 75-18 (1975 WEEK 18). THIS TUBE TESTED 80/86 @ 4000/4300 micromhos.
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One Excellent GE 12AT7 ECC81 Tube. Discriminating Results from the AMPLITREX Tube Tester. AMPLITREX AT-1000. Grey Plates. Strong & Balanced GM. GM Takes Precedence Over EM. GM [%] : 96/96. Strong EM > New Tube, Long Life.
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Please look at ALL photos for details on this item Selling as is Came from collector Resistor Box #3 LRoom shelf ***41
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Tested on a Hi End Maxi-Preamp II tester for Gain (Mu), Transconductance (Gm), and Noise (dB). It most likely is because it has a lower gain compared to the 12AT7. Gain (Expected Value=40 mu). This is very important!
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