Retrovox - Mullard EL38 - CV450 output pentodes. NOS 1960s. Similar spec to EL34. Pinout same as EL34 except anode/plate connection is top cap, not pin 3. Gives better anode isolation and
6AT6 | BRIMAR | DUO DIODE-TRIODE TUBE At 2 € HT on Electols
Sylvania Technical Manual 1949
6AT6 GE Duplex-Diode High-Mu Triode Vintage Miniature Vacuum Tube 7-Pin NOS New Old Stock in Box
6AV6 Datasheet(PDF) - General Electric Company
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NOS NIB Raytheon 6AV6 Vacuum Tube Audio | Inox Wind
6AV6 GE Duplex-Diode High-Mu Triode Vintage 7-pin Miniature Vacuum Tube in BOX NOS New Old Stock