Every tube in this archive, drawn as a bottom-view socket. Hover, tap, or focus a pin to name it — grouped by base so the shared wiring is easy to see. The pins that carry B+ are marked in oxblood.
It's a bottom view. Each diagram shows the tube from underneath — the way the socket faces you from the solder side while you wire it. Turn a real tube over and its pins line up with the drawing. (Look at the tube from the top instead and the order mirrors, which is how miswired sockets happen.)
Find the index, then count clockwise. A noval or 7-pin miniature tube has a wider gap in its ring of pins; an octal tube has a keyed centre spigot. Hold that gap or key at the bottom, and pin 1 is the first pin to its left. The numbers run clockwise from there — up the left side, across the top, down the right.
The code is a standard. The short label on each diagram — 9A, 7BT, 7AC, 5T, 5DA — is the RETMA/EIA basing designation: a fixed name for one arrangement of elements on the pins. Tubes that share a code share a socket wiring, which is why the 6V6GT, 5881, and KT66 all read 7AC and drop into the same output-stage layout. Every map here is read straight from the manufacturer datasheets linked on each tube's page.
The small-button nine-pin preamp bottle. Both of these are dual triodes — two independent gain stages in one glass, their pins interleaved around the ring.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · noval 9-pin (B9A) · basing 9A
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
High-mu (µ=60) twin triode with low plate resistance and high transconductance — a strong current driver.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · noval 9-pin (B9A) · basing 9A
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
High-mu (µ=100) dual triode — the universal gain stage, cathode follower, and phase inverter of guitar amplification.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · noval 9-pin (B9A) · basing 9A
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Medium-mu (µ=44) dual triode — a lower-gain, lower-noise first stage.
The seven-pin miniature base — one detector-triode preamp tube in this corpus. Only the triode plate carries B+; the two diode plates sit idle here.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · miniature 7-pin (B7G) · basing 7BT
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Twin-diode / high-mu (µ=70) triode.
The eight-pin octal base with its keyed centre spigot. The beam-power output tubes all follow the 7AC arrangement: plate on 3, screen on 4, control grid on 5 — both the plate and screen sit at B+.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing 7AC
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Beam-power output tube — the original coke-bottle 6L6/6L6G, lettered on the Fender 5F4 Super "C-EG" drawing.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing 7AC
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Beam-power output tetrode — the low-wattage American output tube.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing 7AC
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Beam-power output tube of the 6L6GC / 5881 family — the higher-power American output tube.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing 7AC
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
British beam-power tetrode from GEC / M-O Valve Co.
Same octal base, different job. In the directly-heated 5Y3 and 5U4 the filament is the cathode, so it floats at B+ alongside the plates; the GZ34 (5DA) adds a separate heater but ties its cathode to pin 8. On a rectifier, nearly every pin is hot.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing 5T
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Directly-heated high-current full-wave rectifier — the supply rectifier of the larger tweed amps such as the 5F4 Super, where the 5Y3 could not pass enough current.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing 5T
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Directly-heated full-wave rectifier — the low-current rectifier of the small tweed amps.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing K8A
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Mullard/Philips A.F.
Hover, tap, or focus a pin to name it.
Viewed from below (socket / wiring side) · octal · basing 5DA
⚡ Oxblood pins sit at B+ — hundreds of volts in service, lethal, and still charged after power-off.
Indirectly-heated full-wave rectifier — a low-drop, slow-warmup rectifier that supplies the tweed 5F6-A Bassman and the JTM45.
Pin maps are transcribed from the manufacturer basing diagrams — RCA, GE, Tung-Sol, Mullard, Philips and GEC — linked on each tube's reference page, and cross-checked against a second sheet where one is available. The socket drawings are redrawn here, never traced from the source documents.