Sigmas Input Switch JK🐉

Sigmas are the noise schedule - the per-step list of noise levels that tells the sampler how fast to descend. Different schedules (a Karras curve vs a linear one) are different feels, and Sigmas Input Switch JK🐉 lets you park two SIGMAS wires in the graph and choose between them with a boolean.

It's part of the same "Noise | Guider | Sampler | Sigmas switch" set Jake added in v1.5.0 for the Flux KSampler workflows. When you want "Karras for draft, exponential for final" without editing a scheduler node between runs, this is the switch.

How it works

if sigmas_true is not None and boolean_value:
    return (sigmas_true, boolean_value)
else:
    return (sigmas_false, boolean_value)

• boolean_value - True → the "true" sigmas, False → the "false" one.
• sigmas_false - required.
• sigmas_true - optional; unplugged = pass-through.

Outputs: sigmas_output (SIGMAS) and boolean.

SIGMAS is the type that flows from a scheduler node into an advanced sampler (the KSampler(Advanced) family and its Flux/Wan equivalents). Both schedules still get computed every run - this is a router, not a lazy evaluator - but sigmas are just a short tensor, so that's pennies of compute.

Where you'd use it

The classic pattern is comparing two sampler configs: "Karras, 20 steps" vs "exponential, 20 steps" on a toggle, so you can see which produces the detail you want. Or pair it with a step-count switch so one boolean flips both the schedule and its length. In JakeUpgrade's Flux sampler group nodes, sigmas get shuffled around constantly - high+low two-pass sampling (the KSampler High+Low nodes) is basically a sigmas manipulation exercise, and this switch is how a graph offers schedule A or B.

Install

Part of ComfyUI-JakeUpgrade. ComfyUI Manager → search ComfyUI-JakeUpgrade, or:

cd ComfyUI/custom_nodes
git clone https://github.com/jakechai/ComfyUI-JakeUpgrade
cd ComfyUI-JakeUpgrade && pip install -r requirements.txt

Nothing extra. Menu: 🐉 JK/🔀 Switch. Standard pack notes: ignore the Manager IPAdapter Plus conflict warning (replacement folder), and if the switch menu is missing check ENABLED_MODULES in config.ini. If you're not using advanced samplers yet, this node will make no sense until you are - then it'll make all the sense.