Need help selecting choke filter - Printable Version

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+--- Thread: Need help selecting choke filter (/showthread.php?tid=16395)

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Need help selecting choke filter - Tamurphy67 - 03-18-2017

I just finished restoring a 40-180. It works fine, but the 12 inch speaker has a big hole in it. Instead of re-coning the speaker. I decided to replace it with a PM speaker I got for 16 bucks.  good speaker actually. So I need to replace the choke. The original speaker has an 1100 ohm choke/ magnet. The radio draws  60watts. the chokes I find online that are rated for 500ma only have a resistance of 50 ohms. So should I choose this choke and add a 1K ohm 10 watt resistor to match the original speakers resistance? I initially installed a choke with a resistance of around 1100 ohms which matched the original coil's resistance, but it gets a little warm when running, and it's rated at just 35ma. 

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RE: Need help selecting choke filter - Radioroslyn - 03-18-2017

500ma is WAY to much! What you are looking for is something around 60-75ma. Here's a 15H choke https://www.tubesandmore.com/products/filter-choke-hammond-open-bracket-15-h-75-ma
The resistance is a bit lower than your fc. If you don't use a series resistor it will increase the HV. With that being said don't think it's going to make much of a difference as the maximum plate voltage for the tubes in your set is greater.

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