Hi All! Never owned an SRR-13 or its kin, its funny but when I was a kid, I was warned away from them BECAUSE of the wire leaded glass tubes. As a result, when I was DRMO "shopping" in the '70's, I avoided 'em! Goes to show bad advice can come from anywhere! The russians perfected the minitube, they never left it. In Oct of 1989 I did some Foreign Material Evaluation at Redstone in Huntsville for the day job, the subject was a Soviet Air-to-Air missile. I was looking at the microwave radar portion (actually figured out some things!). The thing was full of the glass wire leaded pencil tubes, but all one type! Ran on 28 V filament AND plate! There were also canned op-amps, TO-3 style transistors and DIP IC's, so on. I asked one of the Army engineers whats with the tubes: his answer-Impedance converters- acted as buffers for the actuators because they didnt have power fets (hi Z to lo Z). And here I thought it was because they were antiquated. The rough estimate of the missile cost was $50K. (Our equivalent was ~$500K) Also tubes are rad hard but there were semi's there so didn't matter much. The russlies probably still make them - I have about two gross of a russian pencil tube, a common triode. I remember all the surplus I got in the '60's that had the Sylvania tubes, transistors kinda ate their lunch here in the USA. Memories! 73 Jeff Kruth