H3 Sampler by Name (STRING -> SAMPLER)

H3 Sampler by Name is a plumbing node with a specific, annoying job: turn a plain STRING into a real SAMPLER object so one master widget can drive sampling settings everywhere. It exists because ComfyUI's frontend refuses to link one combo box to another - the type check rejects combo-to-combo links. But a STRING output feeding this adapter gives core SamplerCustomAdvanced a genuine SAMPLER it can use. So in a multi-stage H3 graph you wire one control to several of these, and every sampler in the chain follows a single setting instead of drifting apart.

That's the whole point of the "one source, both stages" design this pack pushes. A two-stage chain has duplicated settings on different nodes, and editing one and forgetting the other produces mismatched renders that fail at the concat - or worse, succeed at two different qualities. This node is the wire that makes one source possible.

How it works

Nothing mysterious. Feed it a sampler name and it calls ComfyUI's own comfy.samplers.sampler_object(name) - the same lookup KSamplerSelect uses - and hands back the object. Any name KSamplerSelect would offer works: euler, res_multistep, res_2s, and the rest of the ~44 in current ComfyUI.

If you feed it a name that doesn't exist, it raises a ValueError that lists the valid options. That error is the friendly part - you'd otherwise be chasing a silent mismatch.

The input that matters

Just one: sampler_name (STRING). It's a forced input, meaning it expects a wire rather than a typed value - the whole design assumes another node is supplying the name. Wire it from your master control node (like H3 Studio Controls) or from a PrimitiveString.

The single output is SAMPLER, which plugs into a custom sampler's sampler input. In the shipped H3 workflows you'll see it paired with H3 Sigmas by Name, because those two adapters together let one panel control the entire sampling configuration of the graph.

Installing it

It's part of ComfyUI-H3-Multishot:

cd ComfyUI/custom_nodes
git clone https://github.com/jlucasmcrell/ComfyUI-H3-Multishot

Or search H3 Multishot in ComfyUI Manager. Needs ComfyUI v0.30.0+; the pack adds no Python dependencies of its own.

Gotchas

The only way to trip this up is to wire a literal text widget straight in and expect it to behave like a dropdown - it won't, because the input is forced. You need a node upstream that produces a STRING. That's not a bug; it's the entire point, since a shared STRING source is what a master control panel outputs. If you're seeing "unknown sampler" errors, check what's actually producing the string - a stale name from an older ComfyUI version that dropped a sampler is the usual culprit.