Avalon’s 2022 and Joe Meek’s VC-1 both have an "impedance matching" circuit, consisting of a resistor network placed AFTER the load is already terminated. This is not at all the same thing. Some vintage mic pres (like Neve modules) can be internally hard-wired to one of two different impedances. Vipre is the only preamp we know of with a front-panel selectable, truly variable impedance transformer.