Forming filter capacitor??

bahady30 · Post by **bahady30** » Mon Nov 09, 2015 8:47 am

Hello there. I have a question about forming NEW filter capacitors. For safety reasons I decided to swap out my existing 36 year old filter capacitors so I ordered new 50uF + 50uF 500 V capacitors from F&T . Some people say you have to form them , some say you don't . My supplier in Holland says it's not necessary for new F&T cans because they are new but it is always better to do on NOS ones.I read something on this forum about forming with a resistor between the rectifier diodes and the first filter can . When the voltage across that resistor is <5 Vdc then they would be formed. Does Marshall or Fender does that in their factory?? Do you all form your new filter capacitors?

My amp is a 1980 JMP 2104 combo and there goes a red wire from the diodes to he 500 mA fuse and from the same point a yellow wire goes to the positive terminal of the first filter can. What is the best place to put the resistor ( 100K 2W ).

Thanks for helping me out on this because I'm a bit confused by this.