G.E Pair (2) JAN 6550A tNOS AT1000 TESTED Vacuum Tubes military perfect matched pair 0% 500V test premium Beam Power 42 Watt 1986

This listing is for a Pair (2) of JAN 6550A Beam Power 42 Watt vacuum tubes in the straight-walled glass tube shape. They have a metal octal base, grey 3-hole plate, and triple halo getter.

These two are perfectly matched in plate current! Tested at 500V on the plate.

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 by the power tubes: The plate current must measure between 45.6 mA and 68.4 mA AND transconductance must measure between 5120 uMhos and 7680 uMhos, consistent with original 1986 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 5.7 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!

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 will receive! SKU 6550A-01, SN 400164 and 400168. Please note that matching is nearly always possible for us from stock that is inventoried but not yet listed. If you need a matched pair or quad etc., please use the make-an-offer feature through Reverb. Matching requires an extra burst of effort, so please add $5 per tube to your offer for 10% matching and $10 per tube for 4% matching. [Matching is based on plate current for power tubes, voltage drop for rectifiers, and GM for all other tubes. If you also require the label or internals to match, please specify that in your offer.]