Hi, I have a Krell amp that I want to recap. It requires 4ea 13,000uf/63V filter caps in the power supply. I can't seem to source this value, but I can source 15,000uf/63V. Do you guys see a problem going up 2k in capacitance if the size fits properly? Thanks!
Not at all a problem. Just make sure that everything fits, height, diameter, and pcb footprint/holes.
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12000 uF and 15000 uF are standard values. Either will work fine, but going up in capacitance would result in less ripple and more energy storage, which can be handy for heavy bass thumps.
I'd go with caps that are rated for operation at 85 ºC for 5000-10000 hours or 105 ºC for 2000-5000 hours (or more).
Tom
I'd go with caps that are rated for operation at 85 ºC for 5000-10000 hours or 105 ºC for 2000-5000 hours (or more).
Tom
I would also check the BRIDGE RECTIFIER for the peak current rating as the capacitance has increased by 15.4% which may cause a new failure problem.
What is/was the old cap specified ratings?
Duke
What is/was the old cap specified ratings?
Duke
Audio1Man's advice is sound. I've seen many diodes and or bridges bite the dirt because someone installed oversized caps. Sure, there is a possibility that the diodes won't die but for a few minutes work and a few dollars you can put in more robust diodes or diode bridge. Also... one might also bypass the filter caps with a 100mfd each and bypass them with .1's. This will make the bass sound better and less mud like.
Thanks for the advice! I don't have a problem changing the rectifier; I will need to look at the existing arrangement. BTW, the amp is the KST-100 if anyone is familiar and suggests upgrade?
According to the schem I have; bridge rectifier KBPC2508; peak current on data sheet I found 10uA
According to the schem I have; bridge rectifier KBPC2508; peak current on data sheet I found 10uA
The KBPC2508 is an 800 V, 25 A bridge. 10 uA is probably the max leakage current.
When that amp was built, tolerances on electrolytic caps on the order of +100/-50% were common, so I wouldn't worry about a ~20% increase (12000 -> 15000 uF).
The concern is valid, though.
Tom
When that amp was built, tolerances on electrolytic caps on the order of +100/-50% were common, so I wouldn't worry about a ~20% increase (12000 -> 15000 uF).
The concern is valid, though.
Tom
Well, so much for me relying on the schematic for info. I broke my KST-100 down and low and behold instead of 13,000/63 I find 33000uf/63V! Bridge rectifiers are different too being DB3508P. I guess Krell did some power supply revisions for sure.
They are also screw-in terminals so I'm hoping to find replacements with the same spacings.
They are also screw-in terminals so I'm hoping to find replacements with the same spacings.