The analog head-amp capability a Source advertises — its captured
Source.headAmp (resolved from the patched AdapterInput at patch time), or
NO_HEAD_AMP when the source declares none (a raw/implicit endpoint, a legacy
source, or a genuinely non-REAC PipeWire input). This is what the channel-feature gate
resolves a channel's phantom/pad/SENS advertisement from — undefined source (an
unpatched channel) reads as NO_HEAD_AMP too.
The analog head-amp capability a Source advertises — its captured Source.headAmp (resolved from the patched AdapterInput at patch time), or NO_HEAD_AMP when the source declares none (a raw/implicit endpoint, a legacy source, or a genuinely non-REAC PipeWire input). This is what the channel-feature gate resolves a channel's phantom/pad/SENS advertisement from —
undefinedsource (an unpatched channel) reads as NO_HEAD_AMP too.