I've been winding my out ouput inductors. 16AWG, 1-2uH. While this isn't especially difficult, my "craftmanship" isn't the best looking. Search as I might, I cannot find an "off-the-shelf" source. (If I wanted to order 100-1000, that might be another situation!)
Is anyone aware of a source for ready made output inductors? Must be air core and 18-14AWG, 1-2uH.
Is anyone aware of a source for ready made output inductors? Must be air core and 18-14AWG, 1-2uH.
sreten.
Yup. Pretty much what I've been doing. I've also just discovered that using the theads on a bold of the appropriat diameter and thread-pitch is helpful. Too bad some clever soul doesn't make a 10-ohm resistors specially dimentioned to use as a form. I've made this work on low powered amps, but on higher powered it doesn't work out.
"The low values required for an audio amplifier can be wound on a 2W resistor, any value. "
Well, that's true up to a point. But if I'm anticipating a 100W-150W @ 8 ohm that also can handle a 4 ohm load, I prefer using 16AWG magnet wire. My Wheeler's formula calculator tells me I need a larger diameter and/or length than any 2W resistor I know of has. 18AWG would do it but could get a bit hottter than I care for. I tend to be convervative about wire guage, heatsinks and thermal maters, generally.
Well, that's true up to a point. But if I'm anticipating a 100W-150W @ 8 ohm that also can handle a 4 ohm load, I prefer using 16AWG magnet wire. My Wheeler's formula calculator tells me I need a larger diameter and/or length than any 2W resistor I know of has. 18AWG would do it but could get a bit hottter than I care for. I tend to be convervative about wire guage, heatsinks and thermal maters, generally.
I just dug up this old thread. I made and installed the output inductors. But I am a little concern. I used 14 gauge insulated wire and wound 15 turns on an AAA battery. It's already installed on the pcb. I have second thoughts whether that is optimal.
Is 15 turns too much inductance winding on an AAA battery? Or I should reduce a few turns?
Is 15 turns too much inductance winding on an AAA battery? Or I should reduce a few turns?
Do you have a target or calculated value of the resulting inductors?
Pronine Electronics Design - Single-Layer Air Coil Calculator
Pronine Electronics Design - Single-Layer Air Coil Calculator
Thanks
No, I don't know what value inductor for the output of the power amp driving the speaker.
from the link you gave, My inductor of 15 turn, 0.5" diameter is 1.2uH. The reactance is 7.5ohm @1MHz. The question is whether this value is good or not.
The value is not critical and some here use dangerously low values - should the amplifier be used with unknown/nasty speaker loads.
OTOH, the value should not begin to reduce bandwidth either, if you imagine you need >>20 kHz. I suggest beginning at 3uH and reducing according to your final design testing which, as it hasn't built yet, should still be up for amendment.
OTOH, the value should not begin to reduce bandwidth either, if you imagine you need >>20 kHz. I suggest beginning at 3uH and reducing according to your final design testing which, as it hasn't built yet, should still be up for amendment.
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