OPT WINDER // OUTPUT TRANSFORMER DESIGN CONSOLE

Topology & Tubes

The output stage this transformer sits behind.

Push-pull Single-ended

Output tubes total in the stage

B+ at the plates (V)

Idle plate current, per tube (mA)

Tube optional, for your reference

Target Ratings

What the finished transformer needs to deliver.

Primary impedance (Ω) plate-to-plate for PP, plate-to-load for SE

Power output at full swing (W)

Secondary taps flip every load you want brought out

4Ω 8Ω 16Ω

Low-frequency target (Hz) -3 dB point

Core sizing

Winding Style

Two separate choices: where the screen tap goes, and how the sections are stacked.

No screen tap Ultra-linear Super-linear

Screen tap position % of each primary half from the plate/center-tap end — 20% is gentler/triode-like, 43% is closer to pentode

40%

Sandwich how the primary (P) and secondary (S) sections stack up from the bobbin outward. More P/S boundaries cut leakage inductance sharply, but add interwinding capacitance and winding work.

Primary half arrangement push-pull only — how the two center-tapped halves physically sit in the primary sections

High-frequency target, -3 dB point (kHz) optional — leave blank to skip the interleave check. Needs "bobbin winding width" filled in below to work.

Wire & Build

Sensible defaults are filled in — open this only to override them.

AWG European (mm)

Advanced parameters

Peak flux density override (Gauss) 0 = auto-select from topology

Current density (A/mm²) 2.0–3.0 typical for enclosed audio iron

Bobbin winding width (mm) optional — enables turns-per-layer

Lamination stacking factor

Idle-current imbalance, PP only (%) assumed mismatch between the two output tubes — drives the "insurance" air gap

Available window depth for windings (mm) optional — radial space in the bobbin, checks the wire actually fits

Output Module

Fill in the console and press "Calculate winding spec." Core size, turns counts, wire gauges, and a layer-by-layer winding order will appear on this screen.