Sylvania ONE (1) JAN-CHS-5931 brown base rectifier tNOS AT1000 TESTED Vacuum Tubes balanced premium rugged 5U4GB Audio 1958-1970

This listing is for this JAN-CHS-5931 rectifier rugged 5U4GB triple mica vacuum tube in the straight-walled glass tube shape. It has a brown micanol octal base, black plate, and D or Halo top getter.

These are built like the Bendix Red Bank tubes, with Brown bases and very heavy construction.

Your tube has been fully tested on a computer-regulated, USA-made Amplitrex AT1000 with balanced elements and like new, NOS results (tNOS). Here's what that means: to qualify for this listing, several stringent conditions must be met: The forward voltage drop (associated with sag) in the two sections must be balanced within 10% of each other, and that voltage must be between 21 and 28 Volts for both sections, consistent with original 1958 RCA, Western Electric, Sylvania, GE, and/or Tung-Sol datasheet specifications for new tubes of this type. The tube must also show no shorts. The tube might have mechanical wear or have the label rubbed off - these are very old! Unbalanced and 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!

SKU 5U4-5931mil. SN 400231.

This is not a stock photo - you get this tube and box as photographed!