I have an old Heathkit AA-1800 power amp. This is a beast of an amp, rated at 250v per channel. Since this is almost 40 years old, I'm thinking that it might be a good idea to replace the capacitors in the power supply. There are two 13,000 uF capacitors, rated at 100v. The outputs from the power supply are + and - 100 volts, which seems way too close to the output - which actually measures slightly higher than 100 v. Unfortunately, it isn't easy to find electrolytic capacitors at this size, and voltage ratings seem to be 100v or 200v, with nothing in between. Is going with 100v replacements too risky?
Seems risky. There are 150V parts but it's tough to find anything in stock or that you can buy just a couple of. I doubt the value is very critical. I usually have good luck with caps from Allied, now RS. Maybe this or similar- https://us.rs-online.com/product/cornell-dubilier/cgs123u150x5l/70187064/
FWIW, given the cost of big caps, I measure them for value, leakage and dissipation factor. If everything is good, the chance of failure in the near term is near zero. They stay.
FWIW, given the cost of big caps, I measure them for value, leakage and dissipation factor. If everything is good, the chance of failure in the near term is near zero. They stay.
No it's not risky if you get new caps from a half-decent manufacturer, which will have an appreciable surge rating on top of the working voltage rating. And a new cap will be denser, so you get a nice bump in capacitance too.
There ought to be 160V parts available, elect cap voltages are usually on the R5 series, ie 10, 16, 25, 40, 63, 100, 160, 250...
That’s convenient because when the cap blows up it is sealed inside another can! Genius!
Thanks for the input. My line voltage runs about 122v, and the voltage at the capacitors is slightly over 100v. I didn't reopen the amp to measure again, but that's my recollection.
Unfortunately, many of the reputable supplies want a minimum order of 10 capacitors, so I guess I'll stick with the original one for a while longer.
Unfortunately, many of the reputable supplies want a minimum order of 10 capacitors, so I guess I'll stick with the original one for a while longer.
Mouser is very cheap on this, only $40 each. 18000uF, 160V
Do they fit, diameter is 2". I wouldn't wait long, only 4 in stock.
https://www.mouser.com/ProductDetail/Cornell-Dubilier-CDE/DCMC183T160BF2B?qs=zv9oXRM5khj0jamhYNvY7g==
https://www.digikey.com/en/products/detail/cornell-dubilier-electronics-cde/DCMC183T160BF2B/7388111
Do they fit, diameter is 2". I wouldn't wait long, only 4 in stock.
https://www.mouser.com/ProductDetail/Cornell-Dubilier-CDE/DCMC183T160BF2B?qs=zv9oXRM5khj0jamhYNvY7g==
https://www.digikey.com/en/products/detail/cornell-dubilier-electronics-cde/DCMC183T160BF2B/7388111
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I think all the capacitors are made like that these days lol. It's rare to get the stated capacitance value. Years ago, they were always bang on or over the stated capacitance. Nowdays, it seems to be acceptable to sell them under the rated stated capacitance brand new. Must be getting old...