Look up a tube
Datasheet, pinout, models and sourced specs for every tube in the catalog.
Vacuum tube reference & design toolkit
Learn, design and compare vacuum-tube circuits — datasheets, SPICE models and interactive loadline calculators.
315 tubes · 276 SPICE models · 12 engines · 55 guides
Where do you want to start?
Design a stage
Guided topologies, solved operating points, exportable bill of materials.
Open the Stage DesignerProven example: Plexi V1 (12AX7) →Compare variants
Specs and curves side by side, for any two or three tubes.
Open the comparatorClassic match-up: EL34 vs 6L6 →TP1 — 276 SPICE models
STAGE 01 · GAIN
Every tube has a voice.
Drag the Q-point across the plate characteristic curves and watch power, distortion, and gain respond in real time. 276 SPICE models ready for simulation.
01
Choose315 vacuum tubes. Full specs, datasheets, Koren SPICE parameters.
02
ConfigureSupply voltage, bias, load. SE or push-pull. Class A, AB, or B.
03
AnalyzeOutput power, H2/H3 distortion, gain, impedance. Transfer curves.
B+300V
Ra220kΩ
Vg-1.59V
TP2 — 11 Circuit topologies
STAGE 02 · TOPOLOGY
Stage Designer
End-to-end design wizard for every classic tube amplifier stage. Pick a topology, select your tube, set operating conditions — get a complete design with schematics, component values, and performance predictions.
- 11 topologies
- RDH4 · Reich · Terman formulas
- E24 resistor snapping
Common Cathode12AX7
Select a topology — the schematic redraws.
TP3 — 12 Simulation engines
STAGE 03 · MODEL
12 engines. 276 models.
Not just Koren — the world's most diverse vacuum tube SPICE library. Cross-validated across engines with consensus scoring. Download .subckt files for LTspice and ngspice.
TRY THE CALCULATOR →$ ampera spice --tube 12AX7 --engine koren
* 12AX7 twin triode — Koren (1996)
.SUBCKT 12AX7 A G K
E1 1 0 VALUE={V(A,K)/600*LN(1+EXP(600*(1/100
+V(G,K)/SQRT(300+V(A,K)^2))))}
G1 A K VALUE={PWR(V(1),1.4)/1060}
.ENDS
✓ datasheet: μ=100 · rp=62.5k · gm=1.6 mA/V
✓ cross-checked: ayumi · leach · adrianQ3 · +9
→ 276 models · 12 engines · LTspice + ngspice
KorenAyumiLeachAdrian Q3VanderbijlRydelCohen-HélieDempwolfSjursenCardarilliBroydeDuncan
TP4 — 55 Interactive guides
STAGE 04 · COMMAND
One palette. Everything.
Tubes, guides, glossary, topologies, manufacturers — searchable by alias, by filter, by natural language. Four corpora indexed. The fastest way to anything on Ampera.
- Semantic ranking — "warm preamp triode" finds 12AX7
- Inline filters: type:triode mu>50 maker:mullard
- Compare basket — pin tubes, fire /compare
⌘K
300B
300B — Loadline
2A3 vs 300B
TP5 — 315 Vacuum tubes
THE COLLECTION
315 Vacuum Tubes
From octal-base power triodes to miniature noval preamp tubes — each entry includes full electrical specifications, pinout diagrams, sonic character descriptions, operating presets, and SPICE model parameters where available.
FULL CATALOG
The rest of the bench.
Encyclopedias, learning paths, pro tools, a century of history — everything below is one click deep.
Start designing.
315 tubes · 276 SPICE models · 55 guides · Free & open
Independent technical companion — always cross-check with official datasheets