Inductor for output of power amp?

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I want to buy an inductor that connect from the output of the power amp to separate from the speaker, peak current is 9A. I know people said wind my own onto an AA battery. I just want to see whether I can buy one. What value the inductor should be? What core can I use?

Also, if I do wind my own, what gauge wire I use and how many turns?
 
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Are you referring to the inductor in this circuit. Often a manufacturer will use
about 24 turns of # 18 wire around a 10 ohm 2 w carbon resistor. This should
only have a DCR of about .01 ohm.
 

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0.7uH equals 7 or 8 Turns of 1.4mm diameter enameled copper wire wound around a 15mm diameter bobbin.
Overall length ~12mm, overall diameter ~18mm, overall resistance ~5milli-ohms allowing ~15mm for each tail.

Instantaneous peak power that needs to be dissipated during the off duty cycle = Ipk²R ~405mWpk and drops ~45mVpk from your transient peak output at the speaker terminals.
 
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0.7uH equals 7 or 8 Turns of 1.4mm diameter enameled copper wire wound around a 15mm diameter bobbin.
Overall length ~12mm, overall diameter ~18mm, overall resistance ~5milli-ohms allowing ~15mm for each tail.

Instantaneous peak power that needs to be dissipated during the off duty cycle = Ipk²R ~405mWpk and drops ~45mVpk from your transient peak output at the speaker terminals.
Yes, I just want to know if I want to buy an inductor, with is the value? Also, can I use ferrite core, steel core or has to be air core.
 
If you're off by a factor of two in either direction it won't hurt anything. There is no need for an exact value, unless you're at the point where you can measure your results very accurately. Any inductance you get from an AA battery or 2 watt resistor will keep your amp from oscillating or going .poof from typical capacitive loads.
 
0.7uH equals 7 or 8 Turns of 1.4mm diameter enameled copper wire wound around a 15mm diameter bobbin.
Overall length ~12mm, overall diameter ~18mm, overall resistance ~5milli-ohms allowing ~15mm for each tail.

Instantaneous peak power that needs to be dissipated during the off duty cycle = Ipk²R ~405mWpk and drops ~45mVpk from your transient peak output at the speaker terminals.
I just bought a roll of #14 gauge insulated wire to wind the inductor. I vaguely remember someone mentioned #16, but when I looked at it, it's quite thin.
 
No, those low resistance should be insignificant with a connector to the speaker out there.
Peavey used 16 turns of about 1 cm on their 5 output transistor pair PV-1.3k. Air core. Looks like I'd wind it around a china marker, a little smaller than a AA battery. Peavey calls that "0.8 mh". But the size is not critical, Dynaco wound 11 turns insulated wire around a 1.5 " diameter electrolytic capacitor for theirs. No CB radio transmissions in that amp either. Like I used to get in my mixer before I put inductors on the power supply feed. **** redneck drives around transmitting "dixie" in beeps on his CB rig when he is not mouthing off. I have a red neck from work in the fields in the summer, but I don't transmit continuously.
 
I can't believe you started another thread just for the inductor ? 😕

"Air core inductor calculator" , brings up 25k results.

Air Core Inductor Coil Inductance Calculator

I don't see many high-current 1-2uH coils for sale , as most apps
are DIY or in house OEM. You will have to use the battery (.6"d /1"/16T = 1.7uH)
... 18ga.
For a given gauge , you will have to figure how many turns = 1".
18 is @ 10A ... this is what I use.

OS
 
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Key components 😉

Yeah... nothing really special. I use 1.2mm wire (Welleman), 12 turns around my "magic" 8mm plastic pen 🙂

Perfect for the purpose, exactly, as OS just mentioned - 1-2uH.

Cheers,
Valery
 

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