Ruby Matched Pair (2) EL34A-C 6CA7 tNOS AT1000 TESTED Vacuum Tubes Early China Power Pentode 1980-1992

This listing is for a Matched (10% in plate current) Pair (2) of Ruby-made EL34A-C 6CA7 Power Pentode vacuum tubes in the straight-walled glass tube shape. They have a black bakelite octal base, grey plate, and top halo getter.

Rounded tops with side mica spacers.

These tubes have been selected to match one another for optimal performance! Matching is based on plate current for power tubes, voltage drop for rectifiers, and transconductance (Gm) for other tubes.

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 80 mA and 120 mA AND transconductance must measure between 8800 uMhos and 13200 uMhos, consistent with original 1980 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 10 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 EL34-Rubymp. 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.]