YBA Passion 1000 monoblock power amplifier The YBA Power Transformers
Change is not made without inconvenience, even from worse to better.—Richard Hooker
The YBA Passion 1000's transformers are suspended and shock-mounted to reduce the transmission of vibration to the rest of the circuitry. They're also surrounded with mu-metal shields to improve magnetic isolation. While most manufacturers use toroidal transformers, Yves-Bernard André insists that double-C types sound best. The best comes dear, however; double-Cs typically cost three to five times more to fabricate than do toroids.
Yves-Bernard explains it thus: With a double-C, the primary and secondary windings are separated to avoid what he calls the "negative effects" of the incoming AC power. The isolation between the primary and secondary is high enough that it acts, in effect, as an AC line filter. The windings themselves are made of grain-oriented iron selected, per YBA, for maximum conductivity. The transformers are impregnated (oh, those French) with a special varnish to eliminate air pockets, which reduces mechanical resonance. Most important, the voltage in a double-C drops off slowly, as in a vacuum-tube circuit, while toroids typically exhibit a sharp cutoff point.
M. André: "Double-C transformers act like a source of energy to feed the amplifier's current demand. In this way they are less sensitive to variations in reactive energy on the secondary side."