The EL84 is an audio output pentode used in hi-fi and guitar amplifiers. JJ Electronic identifies its version as EL84 / 6BQ5. Use that identification as a starting point for reading the manufacturer’s information, then check the exact valve and amplifier requirements before ordering.
A manufacturer-specific specification snapshot
The values below are from JJ Electronic’s EL84 manufacturer datasheet. They describe this model; they are not measurements of Glass Audio stock or specifications for every valve carrying a related designation.
- Base: nine-pin NOVAL.
- Nominal heater supply: 6.3 V at 0.760 A.
- Anode dissipation limit: 12 W.
- Screen-grid dissipation limit: 2 W.
- Anode and screen-grid voltage limits: 300 V each.
At its stated typical point, the sheet lists 250 V anode and screen voltages, −7.3 V control-grid voltage, 48 mA anode current and 5.5 mA screen current. Transconductance is 11.3 mA/V at those conditions. Read the complete sheet for all limits and qualifications; this list is not a bias-setting procedure.
What the specification categories mean
Keep heater requirements, limiting values and typical characteristics in separate notes when comparing products. The heater figures identify a supply requirement. Limiting values set boundaries under the manufacturer’s conditions. Typical characteristics describe behaviour at a stated test point. None of those categories alone establishes a safe replacement in a particular amplifier.
For a practical reading method, see how to read a vacuum tube datasheet. Record the manufacturer, exact designation and source beside each value. If two sheets differ, preserve the distinction rather than averaging the figures into a generic EL84 rating.
Does “12 W” mean a 12-watt amplifier?
No. In this sheet, 12 W is the anode dissipation limit. It is not the loudspeaker output rating of a complete amplifier. When comparing equipment, use the amplifier manufacturer’s output specification and its test conditions instead of treating a valve limit as an amplifier power claim.
Check the amplifier before selecting a replacement
- Find the equipment manufacturer’s specified replacement type for the exact model and valve position.
- Record the complete marking on the existing valve, including suffixes, without assuming a previous replacement was correct.
- Check any matching or bias-service requirement in the equipment documentation.
- Ask about the condition and test information for the individual item being offered.
A photograph and a familiar socket do not establish electrical compatibility. If the approved replacement information is unclear, have a qualified valve-equipment technician assess it before fitting an alternative.
Questions to ask when buying
Are EL84 and EL34 the same thing?
No. They are different designations. Do not choose a replacement by the shared letters or by an assumption that one power valve can replace another. Start with the amplifier’s approved type.
Does a datasheet prove that a particular valve is tested or matched?
No. A model specification and the condition of an individual specimen are different records. Ask what measurements are available, under which conditions, and whether any matching claim applies to the actual set offered.
Where can I find the full reference?
Use the Glass Audio datasheet library for manufacturer links, and consult the complete sheet rather than an isolated specification copied into a listing.
Ask a precise stock or compatibility question
Browse the valve catalogue for current listings. Send the amplifier make, model, valve position, exact markings and quantity through the contact page. This article makes no claim about current availability, price or matching of any item.
Valve amplifiers can retain dangerous high voltages after being unplugged. Internal inspection, measurements and bias work require appropriate training; refer that work to a qualified technician.
Primary references and attribution
- JJ Electronic: EL84 / 6BQ5 product identification.
- JJ Electronic: EL84 datasheet, including typical characteristics and limiting values.
Sources checked 15 October 2026. No revision date was established for the sheet. This is an original explanation with selected factual specifications; the original PDF remains hosted by its publisher.