This listing is for USA-made tubes WITHOUT the shield between the two plates. RCA tubes are in separate listings at a premium. We have not found any 6FQ7 made by Tung-Sol, who stopped at the grey-plate 6CG7. Westinghouse tend to have very heavy getter flashing. Sylvania have the narrow long plates with side ridges that were common in their factories. GE appears to be all long-plate. Do not get excited; all the Amperex is just relabeled GE.
Your tubes have been fully tested on a computer-regulated, USA-made Amplitrex AT1000 on Fixed Bias setting with like new, NOS results (tNOS). Here's what that means: to qualify for this listing, several stringent conditions must be met: The transconductance for each section must measure between 2080 uMhos and 3120 uMhos, consistent with original 1963 RCA, Western Electric, Sylvania, GE, and/or Tung-Sol datasheet specifications for new tubes of this type. The tubes must also show no shorts, show a gas current less than 0.9 mA, and a heater-to-cathode leakage of less than 10 microamps (10 uA). The tubes might have mechanical wear or have the label rubbed off - these are very old! Used-testing tubes are available in a separate listing at a significant discount. Every tNOS or Used Good tube you receive from Sound By Doc is guaranteed against failure for 60 days after purchase, an industry extreme!
OPTIONS (use offer feature in Reverb):
Want a regular white box? $1 extra per tube
Want a tube that's packed in its original box? $3 extra per tube
Want the test results recorded on your box, too? $3 extra per tube
Want two tubes that match one another within 10%? [Matching is based on plate current for power tubes and GM for all other tubes] $5 extra per tube.
| Listed | a year ago |
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| Condition | Very Good (Used) Very Good items may show a few slight marks or scratches but are fully functional and in overall great shape.Learn more |
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