Listening #57 Page 2  We've also spoken of transformer
impedances—numbers that describe their primary and secondary
coils—but those, too, can't be understood in isolation of the
gear with which these coils will be used, or even each other.
It's possible to describe the DC resistance of a coil simply by
measuring it, but it isn't possible to describe the AC impedance
of a coil without observing it at work, in a complete circuit
with an exemplary source or load. Consequently, the impedance
specifications published by transformer manufacturers should be
thought of abstractly: For the most part, primary impedance
specs are little more than numbers used to describe the source
load to which that primary is best suited. The 3-ohm label on
the input side of a Tamura TKS 83 transformer, for example, does
not mean that the primary presents a 3-ohm load. (If it did,
there'd be no way to explain why a 5-ohm Koetsu Black exhibits
voltage gain, rather than loss, when driving it!) It means that
the primary is appropriate fo