But being as this is a 7550 dual triode, the most powerful subminiature tube in the world… - Effectrode
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6021 Sylvania Medium Mu Twin Triode Tube. Designed for use as an amplifier in high and UHF circuits. New old stock. No longer available for export. MFR: Sylvania. SKU: 6021.
Usb Power Supply 5vdc Low Voltage Vaccum Tube Amplifier, Audio Buffer Circuit Board, Double Triode 6021 - Integrated Circuits - AliExpress
Micropower subminiature tube guitar amps with reverb and vibrato
Sylvania 1970 Sleeve NOS JAN 6021 1970 | Reverb
JJS.at : Electronic Projects : Class AB Subminiature Tube Guitar Amp