09-20-2025, 11:06 AM
Hi Jeansonne,
First off, welcome to the Philco Phorum. Please take the time to check out the various features, topic forums, rules and regulations, etc., and the "What not to post" entry. Don't forget to stop in at "Old Ron's Bar and Grill for a virtual burger and brew and to shoot the breeze in the various topic threads there.
As to getting speakers reconed, hang in there, some of the other Phorum experts have used various speaker reconing services with very good results. Someone will post info for you.
If you are looking to buy a speaker from a Phorum , please post the request in the "Wanted" Ads section of the "Trading Post" Forum. (Scroll down from the Phorum Home Page.)
I (being cheap) generally replace a field coil speaker with what I have or have scrounged, in some cases, looking to upgrade the existing speaker. If replacing a field coil speaker with a permanent magnet speaker and resistor to replace the field coil, I believe that the caps should be upgraded. For 80s and 5Y3s, I would go to 30 uF for the input filter and as much as 40 uF for the output filter. Do measure the voltage to ensure that it has not gone too high.
Older sets using speakers with field coils got away with smaller caps because, first off, higher capacity caps were not really available.
Secondly, the field coil acted as a choke.
Thirdly, and this is often overlooked, field coil (Electrodynamic) speakers had a "Hum Bucking" coil wound on the same pole as the field coil and wired in a polarity to cancel out induced hum. The number of windings was calculated based on the field coil and cap values using formulae that I don't know.
First off, welcome to the Philco Phorum. Please take the time to check out the various features, topic forums, rules and regulations, etc., and the "What not to post" entry. Don't forget to stop in at "Old Ron's Bar and Grill for a virtual burger and brew and to shoot the breeze in the various topic threads there.
As to getting speakers reconed, hang in there, some of the other Phorum experts have used various speaker reconing services with very good results. Someone will post info for you.
If you are looking to buy a speaker from a Phorum , please post the request in the "Wanted" Ads section of the "Trading Post" Forum. (Scroll down from the Phorum Home Page.)
I (being cheap) generally replace a field coil speaker with what I have or have scrounged, in some cases, looking to upgrade the existing speaker. If replacing a field coil speaker with a permanent magnet speaker and resistor to replace the field coil, I believe that the caps should be upgraded. For 80s and 5Y3s, I would go to 30 uF for the input filter and as much as 40 uF for the output filter. Do measure the voltage to ensure that it has not gone too high.
Older sets using speakers with field coils got away with smaller caps because, first off, higher capacity caps were not really available.
Secondly, the field coil acted as a choke.
Thirdly, and this is often overlooked, field coil (Electrodynamic) speakers had a "Hum Bucking" coil wound on the same pole as the field coil and wired in a polarity to cancel out induced hum. The number of windings was calculated based on the field coil and cap values using formulae that I don't know.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55




