EL34 vs 6CA7
EL34 versus 6CA7 / EL34 — Pentode vs Tetrode compared.
EL34 vs 6CA7: which one to choose?
The EL34 and 6CA7 are directly equivalent in most applications — same pinout, same electrical envelope, same general sonic signature. EL34 is the American/RETMA designation; 6CA7 is the European Mullard-Philips name (or vice versa). You can swap one for the other in nearly every circuit without rebiasing, with the caveat that production-batch differences between manufacturers (Mullard vs Sylvania vs JJ vs current Russian production) often matter more than the type-number itself.
Side-by-side specifications
| Spec | EL34 | 6CA7 |
|---|---|---|
| Full name | EL34 | 6CA7 / EL34 |
| Type | Pentode | Tetrode |
| Primary use | Power (PP) | Power (PP) |
| Era | 1955 | 1956 |
| Heating | indirect | indirect |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 1.5 A | 1.5 A |
| Amplification factor (μ) | — | — |
| Transconductance (gm) | 11 mA/V | 10 mA/V |
| Plate resistance (rp) | — | — |
| Max plate voltage | 800 V | 800 V |
| Max plate dissipation | 25 W | 25 W |
| Base | octal | octal |
| Manufacturer | Mullard·Philips | Sylvania |
| Rarity | Common | Sought-after |
Sonic character
British voice. Marshall tone.
Sylvania's beam-tetrode response to the Mullard EL34 pentode. Pin-compatible and used as an EL34 substitute, but the internal construction is a beam-power tube (aligned beam-forming plates) rather than a true suppressor-grid pentode — so harmonic structure differs subtly from European EL34s.
Need an interactive deep dive?
The Amperatubes comparator visualises loadlines for both tubes side-by-side, simulates the SPICE response, and lets you adjust the operating point in real time.
Open EL34 vs 6CA7 in the interactive comparator →