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Meanwhile a 100% permalloy core cannot handle high levels without gross distortion. Combining the two materials
makes sure each operates at its best. This reduces distortion dramatically, when compared to traditional cores, be they
GOSS, amorphous iron or similar materials.
In order to combine a high step-up ratio with good behaviour without excessive resonances or bandwidth limitations,
our custom transformers use a complicated multi-section winding with both vertical and horizontal sectioning.
Extremely thin wire must be wound precisely and tightly to create the performance we required.
Combining this complex winding with an exceptional core produces a transformer that handles all levels without
obvious distortion as well as oering a completely at frequency response without colorations well past the audio band.
Only with such an exceptional transformer can we approach and even exceed the best transformer-less amplier in
terms of performance.
Commonly the bias voltage is created using the 50/60Hz mains power and a so-called Villard or Greinacher cascade
rectier (which is also sometimes called a Cockcroft-Walton voltage multiplier) is employed. This circuit can deliver very
high voltages using rather generic and inexpensive components, but its operation is noisy.
Given the low frequencies of the AC used, large value capacitors tend to be needed, usually requiring rather nonlinear
electrolytic capacitors, which have high leakage currents and so the cascade rectier must operate constantly to keep
the Bias Voltage from dropping.
At iFi we decided to completely toss out all existing solutions.
The Bias System - Capacitive Battery Power Supply
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