10BQ5 Vacuum Tube – 10V-Heater Output Pentode (EL84/6BQ5 Family)

The 10BQ5 is electrically identical to the 6BQ5/EL84 output pentode except for its heater — built with a 10V heater for series-string chassis instead of the standard 6.3V.

• Tube type: Power pentode
• Base: B9A / Noval 9-pin
• Heater: 10V AC (series-string variant of the 6BQ5/EL84)
• Typical use: Audio output stage in medium-power hi-fi amplifiers and TV/radio sound sections using a 10V heater string

Push-pull pairs deliver up to ~17W; single-ended use yields ~5.7W.