Does this sound like a reasonable idea to try for the constant current choke on a single-ended class A amplifier?
"there is a trick that can actually increase the inductance and mostly cancel core saturation. Take two I-cores, stack them end to end, the closer the better (epoxied together for long term use is best), and run them in reverse magnetic polarity while in series. This can allow you to use a smaller initial value of inductor, and keep core saturation to a minimum. For instance if your goal is 10 mH, you don't need two 5 mH inductors, but more like two 3 to 4 mH inductors, the exact value depends on how closely coupled the cores are.
If you had inductors rated to handle say, 5 amps each, when configured in this manner, they might be able to take 15-25 amps or so, depending on how well matched and positioned the cores are.
Ideal implementation has two bobbins on a single long laminated core, no air gap losses then." (Jon Risch)
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"big thanks Jon , I found two 1mH Madisound steel core inductors and twisted the leads to put them in series. I'm not sure if I got all the permutations available as I didn't change the lead connection - but did change one core's orientation.
Inductance measured ~2.1mH with cores spaced, 1.75mH with in one butted position, and 4.15mH in the other. Did I leave out something as one position was double the inductance? Out of the conditions tested which one is the preferred?" (Fred I)
"there is a trick that can actually increase the inductance and mostly cancel core saturation. Take two I-cores, stack them end to end, the closer the better (epoxied together for long term use is best), and run them in reverse magnetic polarity while in series. This can allow you to use a smaller initial value of inductor, and keep core saturation to a minimum. For instance if your goal is 10 mH, you don't need two 5 mH inductors, but more like two 3 to 4 mH inductors, the exact value depends on how closely coupled the cores are.
If you had inductors rated to handle say, 5 amps each, when configured in this manner, they might be able to take 15-25 amps or so, depending on how well matched and positioned the cores are.
Ideal implementation has two bobbins on a single long laminated core, no air gap losses then." (Jon Risch)
---------------------------------------------------------------------
"big thanks Jon , I found two 1mH Madisound steel core inductors and twisted the leads to put them in series. I'm not sure if I got all the permutations available as I didn't change the lead connection - but did change one core's orientation.
Inductance measured ~2.1mH with cores spaced, 1.75mH with in one butted position, and 4.15mH in the other. Did I leave out something as one position was double the inductance? Out of the conditions tested which one is the preferred?" (Fred I)
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Here is a little reading to start you out:
http://www.diyaudio.com/forums/pass-labs/133433-choky-susy-f3-lu1014s.html
Magura
http://www.diyaudio.com/forums/pass-labs/133433-choky-susy-f3-lu1014s.html
Magura
I guess I should have given more detail, the question was really about the winding technique and core saturation in a DC application.
Do any of you know the answer to that?
"Well, you need much higher inductance. 2 x 80mH is barely enough."
Thanks, I think most people can figure that out.
How much inductance do you think is actually needed for a high frequency amp (400hz and up)? How about for a VHF amplifier (4Khz and up)?
Do any of you know the answer to that?
"Well, you need much higher inductance. 2 x 80mH is barely enough."
Thanks, I think most people can figure that out.
How much inductance do you think is actually needed for a high frequency amp (400hz and up)? How about for a VHF amplifier (4Khz and up)?
Core saturation issues to be more specific.
Magura
It's only an issue if the core saturate.
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