Tested and matched on Hickok 752, just recently calibrated and modified by Hickok expert to all Solid State to eliminate drift. However, on average 12AT7 measures lower on this 752 than it should.

For comparison, 12AT7 measuring 4400-4400 on calibrated Hickok 600 measures 3300-3300 mmhos on this 752. Average new 12AT7 on Hickok 600 is 4000 mmhos. In other words, actual test scores are higher than what we have noted on the tube boxes.

Single Tube = $50. Select 2 for a Matched Pair or 4 for a Matched Quad. Even odd number of tubes will be matched.