Micro-Microphony

Micro-microphony arises wherever components are mechanically excited: by structure borne sound, airborne sound or vibrations of the enclosure. In tube amplifiers this is known as a “microphonic tube”, but electrolytic capacitors, large film capacitors, switch contacts or potentiometer housings are also sensitive. Mechanical motion changes distances and contact areas – capacitance and resistance fluctuate periodically, creating unwanted modulation of the signal.

Micro-Microphony

Micro-microphony acts one level deeper – inside the materials themselves. The polarization of the dielectrics in capacitors, the lattice voltages of resistor layers, magnetostrictive effects in ferrite cores and even piezoresistive changes in thin metal films produce timedependent changes in C(t), L(t), R(t). These micromotions are in the micro to submicrometer range, but through modulation and intermodulation they are effective within the audible band. In amplifier circuits they lead to fine phase and amplitude fluctuations – barely measurable, but audible as a loss of clarity and spatial depth.

In addition, there are the materialspecific micromicrophonic effects that we harmonize through our special patented alloy and minimize by carefully tuned process control in the manufacture of the conductors.

Electrical parameters

Electrical parameters determine the stability of these processes. In power supplies, electrolytic capacitors in particular play a central role. Their classic characteristic values – capacitance, ESR, ESL, leakage current, temperature drift and ageing behaviour – determine response speed and current delivery capability. High intrinsic damping and a mechanically stable design prevent resonances, structurebornesound coupling and the resulting modulation of ESR that can modulate right into the useful signal. This is why highquality audio amplifiers use vibrationdamped electrolytics and reinforced winding mechanics. Low ESR, low inductance (ESL) and a resonancepoor design ensure that current peaks can flow unhindered – crucial for transient response and lowfrequency performance.

In the signal stages themselves, capacitors and resistors dominate. Capacitors in the signal path – for example as coupling capacitors or filter elements – act directly on linearity and phase stability. Their dielectric absorption can lead to fine ringing that appears as a slight softening of detail. The sonic signature of the Micro-microphony of the metal structure also affects the overall result – either uncontrolled and arbitrary, or deliberately used, minimized and harmonized. Resistors contribute to stability and sonic character through their tolerance, temperature coefficient, noise behaviour and Micro-microphony; piezoresistive and magnetostrictive effects can generate subtle amplitude modulations here. PCB traces and solder joints also play a role: minute stresses from material strain or magnetic backeffects influence contact resistances and thus the fine structure of the signal. Here too, Micro-microphony plays an essential role.

PCB materials themselves are increasingly coming into focus. Copper alloys such as Angelique Copper or Angelique SilverGold exhibit improved conductivity and reduced micromechanics. Their microstructure reduces voltage fluctuations at the interfaces and ensures a more even current distribution. Reduced and harmonized Micro-microphony has a positive effect on the sonic performance. The result is an audibly more stable, less coloured sound image – less “selfsound” of the material, more authenticity of the music.

In summary:

• Macro-microphony: electrical generated mechanical movement of complete component structurs, structurebornesound coupling.
• Micro-microphony: internal microprocesses in the material, polarization and lattice motion.
• Electrical parameters: define losses, stability, resonance behaviour and response speed.
  ‍

The further you follow the music signal along the chain – from the power supply through the preamp to the power stage – the more important the quietness of the components becomes. Because in amplification, more than anywhere else, one rule applies: every movement gets louder.

The goal remains the same: the components must be still so that the music can speak. Damp the mechanics, order the fields. The stage grows, voices become real.