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 Post subject: WTB chokes!
PostPosted: Dec Mon 24, 2012 5:29 pm 
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Joined: Feb Mon 28, 2011 11:14 pm
Posts: 272
Location: Detroit, Michigan
Does anyone have any old choke laying around? I need one 30 henry choke, one 1000 henry choke, one 2000 henry choke, one 100 henry choke, and one 25 henry choke. thanks,
john


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 Post subject: Re: WTB chokes!
PostPosted: Dec Mon 24, 2012 10:17 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 6236
Location: Santa Rosa, CA
Are you sure you need 1000 Hy and 2000Hy?

Mighty rare chokes, I'd say.

Rich


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 Post subject: Re: WTB chokes!
PostPosted: Dec Mon 24, 2012 10:27 pm 
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Joined: Feb Mon 28, 2011 11:14 pm
Posts: 272
Location: Detroit, Michigan
Rich, W3HWJ wrote:
Are you sure you need 1000 Hy and 2000Hy?

Mighty rare chokes, I'd say.

Rich

do you think i would be able to locate these?


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 Post subject: Re: WTB chokes!
PostPosted: Dec Mon 24, 2012 10:56 pm 
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Joined: Sep Thu 14, 2006 3:27 pm
Posts: 5866
Location: Carmel, Indiana
Radiosmarts1234 wrote:
Rich, W3HWJ wrote:
Are you sure you need 1000 Hy and 2000Hy?

Mighty rare chokes, I'd say.

Rich

do you think i would be able to locate these?


Even if you did find one, I'm not so sure you'd even be able to lift it.

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Michael Feldt
www.indianaradios.com


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 Post subject: Re: WTB chokes!
PostPosted: Dec Mon 24, 2012 10:58 pm 
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Posts: 8797
Location: SE USA
They are out there but only in very low current ratings , ie less than 10ma. Is this for a choke-coupled audio stage?

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 Post subject: Re: WTB chokes!
PostPosted: Dec Mon 24, 2012 11:39 pm 
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Joined: Feb Mon 28, 2011 11:14 pm
Posts: 272
Location: Detroit, Michigan
heres where im getting this info from. It says henrys but im starting to thing it could be micro henries http://www.earlytelevision.org/pdf/qst_4-38.pdf


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 Post subject: Re: WTB chokes!
PostPosted: Dec Mon 24, 2012 11:56 pm 
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Joined: Mar Fri 14, 2008 1:40 pm
Posts: 8797
Location: SE USA
I'm way out of my league on something like that. What I was aiming at earlier is that often the secondary of an old 1:3 interstage audio transformer will have enough inductance to get by in choke coupling applications.

FWIW - AES has a Hammond P-T156C. 150Hy@8ma.

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Last edited by Jack Shirley on Dec Tue 25, 2012 12:00 am, edited 1 time in total.

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 Post subject: Re: WTB chokes!
PostPosted: Dec Mon 24, 2012 11:56 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 6692
Location: Minneapolis, MN USA
Here is partial product info page for the specified Thordarson transformer.
Jack is correct, it is Henries.

http://antiqueradios.com/gallery/d/1539 ... darson.png


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 Post subject: Re: WTB chokes!
PostPosted: Dec Tue 25, 2012 12:37 am 
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Joined: Mar Wed 28, 2012 11:01 pm
Posts: 117
Location: Toronto, Ontario
Not sure if this is much help...

I found this catalogue: http://www.vintageradio.com/history/Thordarson1947.pdf

Which states that the Thordarson 'T-29C27' is now (as of 1947) named 'T-20C50,' and the catalogue states that the T-20C50 part is a 350H @5mA part, while that PDF you linked states that the T-29C27 is a 1000H part.


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 Post subject: Re: WTB chokes!
PostPosted: Dec Tue 25, 2012 1:47 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 27590
Location: Pocasset, Cape Cod, MA
Choke inductance ratings before about 1950 were "stretching the truth" as they were measured with no DC flowing. I suppose since everyone did it, nobody wanted to fess up and be at a competitive disadvantage. I have identical UTC chokes with different ratings on the boxes.


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 Post subject: Re: WTB chokes!
PostPosted: Dec Tue 25, 2012 7:45 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2390
Location: Seattle WA US
FWIW, the 1945 catalog shows T29C27 as 500 Henrys, at 0.5ma DC current. DC resistance 6150 ohms.
That was a lot of fine wire, and the whole thing only weighted one pound !!

--Chuck


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