When will I ever learn? What have I done?

[Jason G]

I just put in new PS filter caps  ( 45uf 350v) in a ss tube hybred I dont have a variac So I  just fired it up. My amp seems to have 3 power supplies 1 for the power amp ,1 for the tube pre and 1 for the eq/reverb. What an odd amp. I just found and artical that said if you dont have a variac you can put some 100k 2w resisters on in line with the caps till they are charged.
Is that still option or do I need new caps? What did the surge current do to the caps ?

[teemuk]

New capacitors don't have the layer of oxide but it forms as current is applied. As far as I know, if the aluminum oxide of the capacitor is formed too quickly it will not build evenly resulting into a weaker capacitor. The procedure also helps to safely test whether the capacitor still is in working order or not, this is done while reforming. Bad capacitors can heat up and explode.

I'm quite sure you will find more definite answer to your questions from the links below:

http://www.jt30.com/jt30page/micKcaps/Forming-Capacitors.html
http://www.vcomp.co.uk/tech_tips/reform_caps/reform_caps.htm

I do not know about high voltage (or just plainly old) capacitors but I have never bothered to form new, lower voltage capacitors (1V - 80V) bought from store and they have always worked fine. For reliability reasons I have always stayed away from using old electrolytics as well so there has been no need to reform them. Anyway, I suspect your amp is fine even though you did not form the capacitors properly. I'd be curious to know whether the forming process is already somewhat an industry styandard...

However, a word of an advice for the future: You should always use a current limiting scheme when you power up stuff after repair for the first time - not to form caps but to prevent damage in case there is a short or something.

[Jason G]

Well I formed the caps. They charge up at 215v the caps have a can take a surge of 400v so there  is a good chance they are fine. They are new caps not old or nos so maby they can handle that stuff better. So after all of that my amp still hums even when it is not connected to a speaker. The chanle leds flash from one chanle to the next for a split second when the amp is turned on. So I am going to test the diods next. The hum doesnt change when I adjust the volume and there is a hum when there is no speaker. So it must be in the power supply.
Thanks for the help!