ONE RCA 7591A vacuum tube. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). CE date code = October 1968. +100% plate current test results. Tube 1: 11520 micromhos @ 76.2mA plate current emissions.
Item Tag: 7591 7591A
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TWO Amperex 7591A Tubes / Amplitrex Tested STRONG 💪 +100% / Within 2% Gm Match
TWO Amperex 7591A vacuum tubes. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). Tubes test at 10770 and 10600 where 6630 micromhos is pass/fail grade. +100% gm test results / matched within 2%.
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TWO McIntosh 7591A Tubes / B&K Tested Approx 80% / Good Close Pair
Good pair of used 7591 tubes from a McIntosh MA230. B&K Tested. Austin Stereo has over 45 years of experience with tube audio.
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TWO Amperex 7591A Tubes / Amplitrex Tested STRONG 💪 +100% / Within 2% Gm Match
TWO Amperex 7591A vacuum tubes. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). Tubes test at 10740 and 10950 where 6630 micromhos is pass/fail grade. +100% gm test results / matched within 2%.
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TWO Amperex 7591A Tubes / Amplitrex Tested / 90% Gm / Within 1% Gm Matched
TWO Amperex 7591A vacuum tubes. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). Gm matched to within 1%. Tubes test at 9270 and 9320 where 6630 micromhos is pass/fail grade. 90.8% / 91.3% gm mutual conductance.
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TWO Amperex 7591A Tubes / Amplitrex Tested Above 90% / Within 3% Gm Matched
TWO Amperex 7591A vacuum tubes. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). Gm matched to within 3%. Tubes test at 9550 and 9200 where 6630 micromhos is pass/fail grade. 93.6% / 90.1% gm mutual conductance.
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TWO McIntosh 7591A Tubes / Amplitrex Tested Approx 80% / Good Close Matched Pair
TWO McIntosh 7591A vacuum tubes. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). The labels are very faded but the white “M” of McIntosh can be seen. Tubes test at 8370 and 8650 where 6630 micromhos is pass/fail grade.
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TWO Amperex 7591A Tubes / Amplitrex Tested / One SUPER STRONG, Two Good Singles
TWO Amperex 7591A vacuum tubes. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). Tubes test at 11650 and 9690 where 6630 micromhos is pass/fail grade. 133% / 101.6% mA plate current. 114.2% / 95% gm mutual conductance.
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TWO McIntosh 7591A Tubes / Amplitrex Tested /Strong Plate Current/Close Gm Match
TWO McIntosh 7591A vacuum tubes. Tested on Amplitrex AT-1000 tube tester (fixed bias mode). 85.6% / 86.8% gm mutual conductance. Tubes test at 8740 and 8860 where 6630 micromhos is pass/fail grade. Tube 1: 8740 micromhos @ 60.6mA plate current emissions.
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1 GE 7591 7591A Vacuum Tube Tested NOS Calibrated TV – 7
This tester also is used in conjunction with a variac to maintain test results accuracy and consistency. This tube tested at- 68. Average new tube value – 56. I will always list original photos of actual item you are receiving.