Eq inductors
- Thread starter Fablab
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There are generally measurable differences; if they are audible or not is a matter of design thoroughness.
Real inductors offer the possibility to realize high Q filters without any penalty in terms of clipping. They tend to saturate rather smoothly. So-called gyrators (in fact synthesized inductors) can hard-clip. In a floating input EQ (fader connected between + and - inputs of an opamp, RLC between wiper and ground), the voltage across the inductors (and capacitors as well) can be quite high (sometimes higher than the input or output voltage, if the Q is tight).
Gyrators are noisier (particularly around the tuning frequency), which will reflect in the output.
Ther are many kinds of inductors, but most of the current designs use RM ferrite cores. There are different formulations of ferrite, each with its own saturation curve. Those employed at low frequencies tend to introduce a more noticeable signature than those for HF, not only because of the formulation, but also because they have a much smaller gap.
On my commercial designs, I ended up using synthesized inductors for 20Hz up to 1.6kHz, and real inductors up to 20k. That's what gave IMO the most neutral performance.
Real inductors offer the possibility to realize high Q filters without any penalty in terms of clipping. They tend to saturate rather smoothly. So-called gyrators (in fact synthesized inductors) can hard-clip. In a floating input EQ (fader connected between + and - inputs of an opamp, RLC between wiper and ground), the voltage across the inductors (and capacitors as well) can be quite high (sometimes higher than the input or output voltage, if the Q is tight).
Gyrators are noisier (particularly around the tuning frequency), which will reflect in the output.
Ther are many kinds of inductors, but most of the current designs use RM ferrite cores. There are different formulations of ferrite, each with its own saturation curve. Those employed at low frequencies tend to introduce a more noticeable signature than those for HF, not only because of the formulation, but also because they have a much smaller gap.
On my commercial designs, I ended up using synthesized inductors for 20Hz up to 1.6kHz, and real inductors up to 20k. That's what gave IMO the most neutral performance.
