Solid core wire - ok for heaters?
Moderators: pompeiisneaks, Colossal
Re: Solid core wire - ok for heaters?
OK! Agree. Thanks for knocking this bit of basic electronics back into my noggin.
I build and repair tube amps. http://amps.monkeymatic.com
Re: Solid core wire - ok for heaters?
While always wiring in parallel, no requirement that this is one long string. Same wire size as your transformer manufacturer has coming out on the filament secondary is best gauge for first few segments.
Best .. Ian
Best .. Ian
Re: Solid core wire - ok for heaters?
See if you can get this spreadsheet to work for you - you have to enable editing and macros - but this is by far the best calculator I've seen for ampacity in single wires and bundles in electronic equipment. Much more sophisticated and accurate than the electrician's tables that are based solely on circular mils.
This was developed using NASA's Mil-STD-975 for space and military aircraft applications, so obviously it's conservative, but the bottom line is that 22 ga wire is fine for all signal wires and 20 ga for heaters - although going to 18 ga for the power tube heaters provides a healthy safety margin, and is not a problem wiring if you use sockets such as the Belton micalex 8-pin sockets for your power tubes, which have nice big dual solder holes.
I've included a screenshot with typical values in case I can't figure out how to share the xls file.
https://1drv.ms/x/s!Ag-TpoqAJ9n8iTHEjG08a9rPwXS_
https://1drv.ms/i/s!Ag-TpoqAJ9n8iTBbsx-UnIEBYG-m
This was developed using NASA's Mil-STD-975 for space and military aircraft applications, so obviously it's conservative, but the bottom line is that 22 ga wire is fine for all signal wires and 20 ga for heaters - although going to 18 ga for the power tube heaters provides a healthy safety margin, and is not a problem wiring if you use sockets such as the Belton micalex 8-pin sockets for your power tubes, which have nice big dual solder holes.
I've included a screenshot with typical values in case I can't figure out how to share the xls file.
https://1drv.ms/x/s!Ag-TpoqAJ9n8iTHEjG08a9rPwXS_
https://1drv.ms/i/s!Ag-TpoqAJ9n8iTBbsx-UnIEBYG-m