6SN7 vs 6SL7
6SN7GT versus 6SL7GT — two triodes compared.
6SN7 vs 6SL7: which one to choose?
The 6SN7 and 6SL7 share a family but trade gain for headroom: 6SL7 has the higher amplification factor (μ ≈ 70), making it the typical choice for high-gain preamp stages. 6SN7 runs lower μ (20) and is the standard cathode follower / phase-splitter / line-stage triode. They share the same envelope and base — wire them in the same socket and only the operating point changes.
Side-by-side specifications
| Spec | 6SN7 | 6SL7 |
|---|---|---|
| Full name | 6SN7GT | 6SL7GT |
| Type | Triode | Triode |
| Primary use | Preamp / Driver | Preamp |
| Era | 1939 | 1941 |
| Heating | indirect | indirect |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.6 A | 0.3 A |
| Amplification factor (μ) | 20 | 70 |
| Transconductance (gm) | 2.6 mA/V | 1.6 mA/V |
| Plate resistance (rp) | 7.7 kΩ | 44 kΩ |
| Max plate voltage | 300 V | 300 V |
| Max plate dissipation | 5 W | 1 W |
| Base | octal | octal |
| Manufacturer | Sylvania·RCA·Tung-Sol | RCA·Sylvania |
| Rarity | Sought-after | Moderate |
Sonic character
Original 1939 RCA dual triode. Max plate voltage 300 V, total dissipation 5 W (2.5 W per section) — DO NOT substitute into amplifiers designed for 6SN7GTA/GTB ratings (450 V / 7.5 W) without de-rating, you will destroy the tube. Same μ/gm/rp as later variants; sonic 'legend' status driven by NOS Sylvania, RCA grey-glass and Tung-Sol round-plate examples.
Silky, dark.
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 6SN7 vs 6SL7 in the interactive comparator →