Sylvania

5691 / 6SL7GT JAN 3 MICA

89.00 USD

World class Mil. Spec. double triode amplifier tubes manufactured in the United States by Sylvnaia. These fine glass 8 pin octal based tubes, rated for 10,000 hours, come with 3 mica internal supports, thick ribbed plates, top double getters, and black bases. They are glass-etched 5691 U.S.A. and printed in green on base JAN 5691 SYLVANIA U.S.A. 34167. Boxes are military white NATO coded 5960-00-188-6605, delivered in 1977.

Condition

New Old Stock (New in box)

	Tube Matching 6.00 USD by tube
LEARN MORE WHY ? 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. HOW ? 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.