small 49% nickel chokes

Design and use of Chokes for PS, anode and filament use.
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dave slagle
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Joined: Sat Jan 22, 2005 3:54 am
Location: NYC
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small 49% nickel chokes

Post by dave slagle »

did some Z vs. Frequency measurements of a pair.
Attachments
L vs. I
L vs. I
Picture 2.png (39.81 KiB) Viewed 5634 times
impedance vs. frequency.
impedance vs. frequency.
Picture 7.png (12.08 KiB) Viewed 5636 times
dominique
Posts: 26
Joined: Tue Aug 19, 2008 5:03 pm
Location: paris, france

high cdr plate choke

Post by dominique »

hi dave,

thanks for the 1:2 autoformers i got on last monday ;-)

i am already working on a 2-stage amplifier design and i would like to implement a high dcr plate choke for biasing and direct coupling reasons. Do you think a plate choke of 35H at 15 mADC could be wound in order to have a DCR of 4000R approximately ? I was also thinking in adding a resistor in series with the choke to get the expected DC load in case the choke is not resistant enough but not seduced with the idea...

thanks for your comments and suggestions.

regards,
dominique
dominique
dave slagle
Posts: 2038
Joined: Sat Jan 22, 2005 3:54 am
Location: NYC
Contact:

Post by dave slagle »

hello dominique,

I typically use additional resistance above the choke for biasing purposes. When practical i'll size the wire to get the desired DCR and do not have any conclusive data on the differences in sound between the two approaches.

The one thing the high DCR will do is allow a bunch of turns and a large gap so 80% nickel becomes a realistic option. I ran some numbers and things look good. The high DCR allows for the use of a small nickel core and 80% looks entirely possible without an insane price.

dave
ux226
Posts: 3
Joined: Wed May 20, 2015 1:53 pm

Post by ux226 »

Hi Dave,

Is there a way a hacker like myself could carry out measurements like these on some "mystery chokes" I have lying around?

Thanks,
Bjørn
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