A Pleiades filter is just an inductor in parallel with the signal.
By reducing the winding turns the cutoff frequency is increased and even closer mic source distances are possible. The same principle can be applied to a Pleiades transformer ie reducing primary turns thereby reducing primary inductance and increasing cuttoff frequency therefore making the mic focus at a smaller distance. Decreasing primary turns has the added advantage of automatically increasing the transformer turn ratio. So this iautomaticaly makes up gain. The core used to make the Pleiades inductor or transformer is an extremely high inductance index nanocrystalinne cores made by Magnetec. This makes possible Pleiades filters with very few number of turns. Example of a core is Magnetec Nanoperm 073.
A Pleiades filter can compensate for proximity effect even at a next to mouth mic distance minimising feedback at PA systems and virtualy eliminating pop and wind noise although its a good idea not to remove the microphone grill as it does much wind noise reducing work. After filtering the signal is so clear that one can hear the greyest detail from a voice. If high frequency cutoff is needed for reasons explained on other posts this can be done by a Pleiades high cut finger which consist of just one capacitor in parallel with signal.
A Pleiades transformer with its high impedance can drive the gate of a JFET or the grid of a vacuum tube trough a calling capacitor. On following posts Pleiades pre preamplifier are described including an extremely low noise electron tube one powered by 5V only at the the anode (plate). This is achieved by large Megohm resistor from Anode to grid to free electrons.
Such Pleiades pre preamplifiers next to the output of the microphone transformer make dynamic or ribbon microphones so sensitive that play condenser microphones in their own game.
How does a Pleiades filter work?
The microphone output impedance is in series with the inductor and together form a potential divider.
The inductor impedance as usual increases with frequency and makes the microphone output increasing with frequency at 6dB per octave compensating the proximity effect. After the cutof frequency the impedance of the inductor becomes so high that there is no voltage drop at the mic and response contineous to be flat.
How does damping work?
At low frequencies the droping impedance of the inductor (which becomes just it's winding resistance at zero frequency) makes a large current flow through the coil (shorts circuits the coil at LF). This makes the coil behave like a loudspeker but moving in the oposite direction to the cause (sound wave, blast, pop etc) this is Lens law in action being a represantation of concervatiin of energy for if this force were of the same direction as the cause we would have amplification for free, imposible.
This is the same principle as a brake in electric cars by short circuiting the output of the motor when the car is running.
Another way to put it, it's kunitic energy converted to heat.
This creates a very effective pop and wind filter.
Wanted sound is unaffected as at voice frequencies the impedance of the inductor (which increases with frequency) has become large as to no longer be a load on the voice coil, letting it free to move at the pristine quality of your voice.
By reducing the winding turns the cutoff frequency is increased and even closer mic source distances are possible. The same principle can be applied to a Pleiades transformer ie reducing primary turns thereby reducing primary inductance and increasing cuttoff frequency therefore making the mic focus at a smaller distance. Decreasing primary turns has the added advantage of automatically increasing the transformer turn ratio. So this iautomaticaly makes up gain. The core used to make the Pleiades inductor or transformer is an extremely high inductance index nanocrystalinne cores made by Magnetec. This makes possible Pleiades filters with very few number of turns. Example of a core is Magnetec Nanoperm 073.
A Pleiades filter can compensate for proximity effect even at a next to mouth mic distance minimising feedback at PA systems and virtualy eliminating pop and wind noise although its a good idea not to remove the microphone grill as it does much wind noise reducing work. After filtering the signal is so clear that one can hear the greyest detail from a voice. If high frequency cutoff is needed for reasons explained on other posts this can be done by a Pleiades high cut finger which consist of just one capacitor in parallel with signal.
A Pleiades transformer with its high impedance can drive the gate of a JFET or the grid of a vacuum tube trough a calling capacitor. On following posts Pleiades pre preamplifier are described including an extremely low noise electron tube one powered by 5V only at the the anode (plate). This is achieved by large Megohm resistor from Anode to grid to free electrons.
Such Pleiades pre preamplifiers next to the output of the microphone transformer make dynamic or ribbon microphones so sensitive that play condenser microphones in their own game.
How does a Pleiades filter work?
The microphone output impedance is in series with the inductor and together form a potential divider.
The inductor impedance as usual increases with frequency and makes the microphone output increasing with frequency at 6dB per octave compensating the proximity effect. After the cutof frequency the impedance of the inductor becomes so high that there is no voltage drop at the mic and response contineous to be flat.
How does damping work?
At low frequencies the droping impedance of the inductor (which becomes just it's winding resistance at zero frequency) makes a large current flow through the coil (shorts circuits the coil at LF). This makes the coil behave like a loudspeker but moving in the oposite direction to the cause (sound wave, blast, pop etc) this is Lens law in action being a represantation of concervatiin of energy for if this force were of the same direction as the cause we would have amplification for free, imposible.
This is the same principle as a brake in electric cars by short circuiting the output of the motor when the car is running.
Another way to put it, it's kunitic energy converted to heat.
This creates a very effective pop and wind filter.
Wanted sound is unaffected as at voice frequencies the impedance of the inductor (which increases with frequency) has become large as to no longer be a load on the voice coil, letting it free to move at the pristine quality of your voice.
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