This is on winding an air core toroidal Pleiades R,L filter.
Objective: To hear if flat frequency response from producer's brain to listener's brain is possible when a flat (ie bass, mid bass heavy to listener's brain) mic is connected to pins 2.3 XLR.
Also if resistance is high enough so that no external resistor is needed.
Went to Mr. Giatras transformer manufacturing laboratory.
His son very cleverly suggested winding on a plastic toroid used for insulating tape.
Dimensions, outer, inner diameter, height
Do=8.8cm
Di=7.6cm
h=1cm
If 12,000 turns of 0.2mm wire diameter can be wound, inductance should be roughly 43.mH which is great for many mics. No idea what the resistance would be. Let's hope it would be 80Ω to 300Ω.
Another winding of 1/3 turns was ordered on the same toroid. Mic transformer?
If windings are connected in series, phase or antiphase various R to L ratios could be obtained.
When connected to pins 2,3 of a mic L influences high pass cutoff frequency, R influences slope. The mic output impedance plays an important role of cutoff and slope, see previous posts.
Inductance was calculated from the the formula:
L=μο x (N x N x A / 2 x π x r)
or
L=μο(NNA/2πr)
Where
N number of turns
A cross section
r mean radius of the toroid
Everything has to be converted to SI, système international, m, m2 etc
From
Applied Electomagnetics - Plonus - page 268
Later addition:
The coil (resistance,inductance) is ready after a few days. See newer post:
https://euroelectron.blogspot.com/2019/04/resistance-inducstnce-of-pleiades-first.html
Objective: To hear if flat frequency response from producer's brain to listener's brain is possible when a flat (ie bass, mid bass heavy to listener's brain) mic is connected to pins 2.3 XLR.
Also if resistance is high enough so that no external resistor is needed.
Went to Mr. Giatras transformer manufacturing laboratory.
His son very cleverly suggested winding on a plastic toroid used for insulating tape.
Dimensions, outer, inner diameter, height
Do=8.8cm
Di=7.6cm
h=1cm
If 12,000 turns of 0.2mm wire diameter can be wound, inductance should be roughly 43.mH which is great for many mics. No idea what the resistance would be. Let's hope it would be 80Ω to 300Ω.
Another winding of 1/3 turns was ordered on the same toroid. Mic transformer?
If windings are connected in series, phase or antiphase various R to L ratios could be obtained.
When connected to pins 2,3 of a mic L influences high pass cutoff frequency, R influences slope. The mic output impedance plays an important role of cutoff and slope, see previous posts.
Inductance was calculated from the the formula:
L=μο x (N x N x A / 2 x π x r)
or
L=μο(NNA/2πr)
Where
N number of turns
A cross section
r mean radius of the toroid
Everything has to be converted to SI, système international, m, m2 etc
From
Applied Electomagnetics - Plonus - page 268
Later addition:
The coil (resistance,inductance) is ready after a few days. See newer post:
https://euroelectron.blogspot.com/2019/04/resistance-inducstnce-of-pleiades-first.html
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