max DC-current for an unknown PS- Choke?

stigla · 21st January 2003, 11:09 AM

Hello!

I have found a powersupply choke from an old radio. With my multimeter i measured the inductance to be 28H, with a DC winding resistance at 716 ohms. Now, I want to use this one, but I have no clue on the maximum current it can handle before saturating. The core size is the same as for a 10H at 50mA choke that I have... Is there any means as to determine the maximum current?

Stigla

jackinnj · 21st January 2003, 12:44 PM

the easiest answer is to guess from the output tubes which were in the old radio. It will get you in the ballpark.

this choke has very high DC resistance, so it will heat quickly, 716 R and 50ma = 1.79W from P = (I^2) * R

SHiFTY · 21st January 2003, 07:48 PM

Don't destroy a nice old radio for parts!!! Buy the proper ones!!

stigla · 24th January 2003, 01:14 PM

Quote:

Don't destroy a nice old radio for parts!!! Buy the proper ones!!

Heheh, yes of course. I got this radio for 1, thats one, dollar... Someone had painted the beautifull mahogny look-alike finnish with ugly green paint with a normal brush. It looked like s*** and the speaker was useless. I wouldt salvage any such antique beauties if it wherent for that

at the same time I got a pretty much working and magnificent Phillips Master radio. EL84 output with 2 speakers, and a nice Miniwatt mesh EF86 driver!

The output tube was a 7C5 (equal. to 6V6) with a handfull of other Loctal preamppentodes. It is hard to tell, but I suspect that the choke was not handling the anode current of the 7C5, but just the screen supply and the rest of the smaller penodes... The filter cap had obiously blown, leaving the usual electrolyte "guts" on most of the insides...

That should suggest perhaps a current level no higer than perhaps 10mA?

jackinnj · 24th January 2003, 03:48 PM

a.m. radio was never better than in the old consoles -- we had one in the ham radio shack in high school 30 years ago -- could listen anywhere within about 400 miles of the school during the day !

I suggest that a refinishing job on the cabinet might be in order.

Joel · 24th January 2003, 04:07 PM

400 miles? That's nothing

I've done 1,200 with a regenny.

21st January 2003, 11:09 AM	#1
stigla diyAudio Member Join Date: Nov 2001 Location: Trondheim	max DC-current for an unknown PS- Choke? Hello! I have found a powersupply choke from an old radio. With my multimeter i measured the inductance to be 28H, with a DC winding resistance at 716 ohms. Now, I want to use this one, but I have no clue on the maximum current it can handle before saturating. The core size is the same as for a 10H at 50mA choke that I have... Is there any means as to determine the maximum current? Stigla

24th January 2003, 03:48 PM	#5
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	sounds like ? a.m. radio was never better than in the old consoles -- we had one in the ham radio shack in high school 30 years ago -- could listen anywhere within about 400 miles of the school during the day ! I suggest that a refinishing job on the cabinet might be in order.

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21st January 2003, 12:44 PM	#2
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	the easiest answer is to guess from the output tubes which were in the old radio. It will get you in the ballpark. this choke has very high DC resistance, so it will heat quickly, 716 R and 50ma = 1.79W from P = (I^2) * R

21st January 2003, 07:48 PM	#3
SHiFTY diyAudio Member Join Date: Jul 2002 Location: New Zealand	Don't destroy a nice old radio for parts!!! Buy the proper ones!!

24th January 2003, 04:07 PM	#6
Joel diyAudio Member Join Date: Oct 2002 Location: Brooklyn, NY	400 miles? That's nothing I've done 1,200 with a regenny.

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