Tung-Sol GE 2% Tight-Matched Pair (2) 6550 Beam Power Pentode tNOS AT1000 TESTED Vacuum Tubes 3-hole, 3 getters, Coke Bottle premium 1961 - 1970

This listing is for a Pair (2) of 6550 Beam Power Pentode GE vacuum tubes in the ST (Coke bottle) tube shape. They have a nickel collar around brown micanol octal base, no hole (tung-sol) or 3-hole grey plate, and 3 halo getter. These are GE branded; T-S made both.

2% match in plate current!!!

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 plate current must measure between 112 mA and 168 mA AND transconductance must measure between 8800 uMhos and 13200 uMhos, consistent with original 1970 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 14 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 tube you receive from Sound By Doc is guaranteed against failure for 60 days after purchase, an industry extreme!

These photos are not stock photos. You are looking at the actual tubes you will receive. If a box or boxes are in the photos, you will get them. If test results appear in the photos, look close, because those are the test results of the tubes you are buying! SKU 6L6-6550-322mp.