Quick couple of questions on reforming caps in old equipment. First off, this relates to old equip in general, but specifically I'm working right now on a Fisher amp (uses a voltage doubler). I've read over a number of posts on the subject, but the best I've found is advice to replace caps is they have "excessive" hum or "excessive" leakage. What's excessive? I have no hum at all on this amp, even on the phono input with my 97+db Fostex's. The cans get slighlty warm, but they are next to a warm transformer and hot output tubes. I can open the cap circuit and measure dc current flow, but again, I'm not sure what would be considered excessive. Thoughts?
On a related topic, I sometimes pick up an interesting unit on ebay for myself or a firend and then do some restoration on it. Almost always the seller will say, "Well, I plugged it in and all the tubes light up." I'm relatively sure this isn't done on a variac. So... of what value is reforming over several hours with a variac, if someone else has already applied full voltage for some undetermined amount of time? Once you hit the cans with full B+, is there any point to the slow variac method?
Thanks!
Steve
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Topic - Reforming caps - SteveBrown 14:25:44 12/27/03 (17)
- Re: Reforming caps - Raver 04:12:35 12/28/03 (6)
- Re: Reforming caps - SteveBrown 07:03:48 12/28/03 (5)
- Re: Reforming caps - Leestereo 08:05:06 12/28/03 (4)
- Re: Reforming caps - SteveBrown 08:58:08 12/28/03 (3)
- Re: Reforming caps - AudCon 23:05:58 12/28/03 (2)
- Re: Reforming caps - AudCon 23:12:55 12/28/03 (1)
- Re: Reforming caps - SteveBrown 06:03:39 12/29/03 (0)
- Dried out or leaky cap cannot be reformed? - Koo 02:41:03 12/28/03 (0)
- I agree: Just replace them - doodlebug 17:34:04 12/27/03 (6)
- Re: I agree: Just replace them - microbe 22:20:34 12/27/03 (5)
- Re: I agree: Just replace them - doodlebug 20:52:20 12/28/03 (2)
- if an amp is quiet are the electrolytics in fine shape? - microbe 21:21:17 12/28/03 (1)
- Re: if an amp is quiet are the electrolytics in fine shape? - doodlebug 08:31:28 12/29/03 (0)
- I've always just replaced them as a matter of preventive maint. The few times I've ... - PureAudio 06:46:17 12/28/03 (1)
- Blown Electrolytic Story - AudCon 14:26:06 12/29/03 (0)
- Don't mess with them just replace them (nt) - glen65 16:59:10 12/27/03 (0)
- Re: Reforming caps - dr. tube 16:56:31 12/27/03 (1)