EL12N

Power Pentode — Y8A

RFT

Known Equivalents & Substitutes

EL12/425

Similar Tubes (Not Drop-In Compatible)

Same tube family but completely different pin assignments and lower voltage rating (350 V vs 425 V) — not interchangeable

Electrically equivalent but different pin assignments — anode on pin 8 instead of top cap, g2 on pin 1 instead of pin 8. Not pin-compatible.

EL150

Related type with different max ratings — listed as replaceable by Radiomuseum

Electrically similar Philips equivalent but uses B8A base instead of Y8A — not pin-compatible

Electrical Specifications

Section 1 — Pentode

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)425V

Screen Voltage (max)Screen Voltage (max)425V

Anode Dissipation (max)Anode Dissipation (max)18W

Screen Dissipation (max)Screen Dissipation (max)2.5W

Notes

The EL12N eliminates the top-cap anode connection of the EL12spez, bringing all electrodes to the Y8A base pins. Pin assignments differ from both the EL12 and EL12spez — none of these three are interchangeable despite sharing the same Y8A base.
Pin layout: pin 1 = g2, pin 2 = g1, pin 3 = k/g3, pin 4 = NC, pin 5 = h, pin 6 = h, pin 7 = NC, pin 8 = anode.
TDSL lists Vg1 = -0.3 V which appears to be a cathode-bias operating point with self-bias resistor.
Triode-strapped data (shared with EL12/EL12spez family from diyAudio measurements): μ = 18, ra = 1.1 kΩ, gm = 15 mA/V.
Widely discussed in DIY audio circles for SE and PP amplifier projects. Known for stability when genuine RFT production.
Some counterfeit or degraded specimens exhibited thermal instability — test before use.
Produced by VEB Röhrenwerk Mühlhausen (East Germany), also made by Tesla and RSD.

Pin Layout — Y8A

1Screen Grid (g2)

2Control Grid (g1)

3Cathode / Suppressor Grid (internally connected)

Socket-Compatible Tubes ⚠ Not electrically compatible

References