Mystery Chokes

planet10 · 7th October 2005, 09:14 PM

I got given these chokes (2 the same) -- they are substantial, have the sound of liquid sloshing around in them when you shake them (they fellow who gave them to me said oil filled), are rated for very low inductance, but large current capacity.

Can anyone enlighten me as to their purpose?

dave

planet10 · 7th October 2005, 09:15 PM

And a picture of the choke...

SY · 7th October 2005, 09:27 PM

If these are old, that's probably PCB inside...

If I were to guess, these were made for filament or heater supplies.

Sch3mat1c · 8th October 2005, 12:25 AM

Nice stuff.

Considering the apparent age it probably does use PCBs but as long as it stays sealed it's safe (even if it doesn't, its reactivity is debatable so there

).

0.11H is around the critical value for say 300V 1A, so that makes enough sense. No good for less than that critical value, but...

It may've also been used at lower voltage for consequently wider current range, but I don't know anything tubed that would need that kind of power. Could also be early transistor era, but I doubt they would've needed parameters like that with 50s and 60s germanium junk as it was.

Tim

dhaen · 8th October 2005, 05:29 AM

Add 12uF in parallel for a 120 Hz resonator. Connect in series with your DC DHT heaters to reduce hum.

NB Check my math, it's always suspect

JesseG · 12th October 2005, 01:37 AM

Hey Dave:

I tracked down those chokes - they are filled with PCB. They came from the transmitting stage of the Coastguard radio station here in Alert Bay. Westinghouse 20,000 watt HF (240 Khz) transmitter ca. 1940. Removed July 1967.

Same with the trafor and chokes I have - these came from the audio amplifier section (shame this was lost) - it drove about 18 speakers around the site on 75V step-up-down trafors on the speakers (remember the highschool PA system).

Now, you just have to figure out what to use them for.

Cheers

7th October 2005, 09:27 PM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	If these are old, that's probably PCB inside... If I were to guess, these were made for filament or heater supplies. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

8th October 2005, 12:25 AM	#4
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Nice stuff. Considering the apparent age it probably does use PCBs but as long as it stays sealed it's safe (even if it doesn't, its reactivity is debatable so there ). 0.11H is around the critical value for say 300V 1A, so that makes enough sense. No good for less than that critical value, but... It may've also been used at lower voltage for consequently wider current range, but I don't know anything tubed that would need that kind of power. Could also be early transistor era, but I doubt they would've needed parameters like that with 50s and 60s germanium junk as it was. Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

12th October 2005, 01:37 AM	#6
JesseG diyAudio Member Join Date: Jul 2005 Location: Mid coast of British Columbia	Hey Dave: I tracked down those chokes - they are filled with PCB. They came from the transmitting stage of the Coastguard radio station here in Alert Bay. Westinghouse 20,000 watt HF (240 Khz) transmitter ca. 1940. Removed July 1967. Same with the trafor and chokes I have - these came from the audio amplifier section (shame this was lost) - it drove about 18 speakers around the site on 75V step-up-down trafors on the speakers (remember the highschool PA system). Now, you just have to figure out what to use them for. Cheers __________________ "If we crashed our cars as often as we crashed our computers, we'd all be dead!"

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8th October 2005, 05:29 AM	#5
dhaen diyAudio Moderator Emeritus Join Date: Jun 2002 Location: U.K.	Add 12uF in parallel for a 120 Hz resonator. Connect in series with your DC DHT heaters to reduce hum. NB Check my math, it's always suspect

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