• New
Radio Corporation of America

5840 / EF762

17.00 USD

Fine long wire pentode tubes manufactured in the United States by renowned RCA. These subminiature glass tubes, designed for high frequency control applications, are printed in red with RCA logo, MADE IN U.S.A. and glass etched 5840. Boxes are standard RCA red and black printed 5840.


Tube Matching
Tube Matching
6.00 USD by tube


A tube may have one, two, or three internal sections depending on the purpose of the tube; somtimes these sections are all the same, sometimes they are different. Due to manufacturing and material tolerances, there may be slight differences between the original specification and the actual tube. Tube matching tests each one of these internal sections and selects tubes, compared to original specifications at manufacture, for balanced performance and good sound.


All our tubes are tested by us prior to packing on our Stark, AVO, Simpson or RF Laboratories Inc. calibrated testers. On request for tube matching, tubes are matched for Mutual Conductance in Micromhos and Plate Current in Milliamps on our Amplitrex or Radioelec Duovac testers, with results printed for each  individual tube. Certain tubes difficult to test are matched for Mutual Conductance in Micromhos only on one of our regular calibrated testers. On request we can also test for Microphonics.


10 Items

Data sheet

Boite type
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