The Capacitor Replacement Thread

Grim0013 · Post by **Grim0013** » Fri Jan 30, 2009 3:47 pm

I thought it might not be a bad idea to have a single thread discussing the various issues and options when it comes to cap replacement. The intent of this thread is to cover topics such as sourcing capacitors, which specifications to check, what are acceptable substitutions, etc, etc.

Post by **kg1961** » Fri Jan 30, 2009 3:54 pm

need them in my route 66 m44 side but I will do them all info please!!!!!

Grim0013 · Post by **Grim0013** » Fri Jan 30, 2009 3:58 pm

To start things off, I am having a hell of a time finding the proper caps for my MS-2125s. The smaller PS ones seem easy enough to source, but the big rail caps are a bitch. It seems 10,000uf @ 50V is the "biggest" 30x35mm cap available, and on top of that, nobody seems to stock them. Of note, I saw that my 2125TA has 6800uf rail caps, so I imagine going a little smaller doesn't kill you.

Currently, the closest to spec that I have been able to find (in stock) is 8200uf and 85*.
http://search.digikey.com/scripts/DkSea ... e=P6938-ND

Not what I'd like, but it should work. My question however, is how much of an impact do you guys think using these caps would impart?

Also, about the PS caps, they are 2200uf, 16V is I remember right. Is there any benefit to using larger caps there? like these:
http://search.digikey.com/scripts/DkSea ... ?Selection

These are all 16x20-25mm, 10,000 Hours @ 105*, 16V, ranging from 2700-4700uf.

Thanks,
Brad

Post by **kg1961** » Fri Jan 30, 2009 4:04 pm

NICO ,STIPUD, PEDI??? need some help!!!!
you guys have change some or have the item number that work
let us know what works as bigger is better right just like tits!!!!lol

Grim0013 · Post by **Grim0013** » Fri Jan 30, 2009 4:14 pm

From other threads:

Marko:
i tend to leave the rail caps as these don't suffer as much like the psu ones unless there's obvious signs of imminant failure...

Matt:
i will admit that some of the caps are hard to find with exact replacement values... the main thing is the votage and size/dimensions of cap. You dont want anything higher/taller than 35mm for the caps as they will interfere with plexi's and covers and stuff... and the diameter is also just as important as you may find you cant get some to fit within the close proximity of one-another...
BUT you can increase capacitance, if you find that you need to.
The 105's are going to last longer, but 85 is also pefectly feasible (even for a hot running MS1K - per ALEKS at PG.... I couldnt find an exact replacement for the MS1K Original, as the problem was the difference between 85 and 105, but Matt @ PG said the 85's would be perfectly okay.

Stipud
Well, the TA's had lower rail voltages compared to the original amps, so it wouldn't surprise me if they went with cheaper caps to save on costs.

More capacitance = better A/C ripple filtering = better SQ. Assuming the ripple from the PS could be adequately filtered within 4x6800uF caps, you wouldn't notice a difference... not that having more would hurt.

There is A/C ripple from the alternator, which is what the input caps take care of. Then the power supply converts your 12v to the higher ~50v rail voltage, so you need rail caps to filter out the ripple from that transformer as well.

When D/C is created by the alternator, it creates many out of phase A/C waves and uses a rectifier diode to chop off the "tops" of the waves to make a D/C signal. Some of the A/C waveform will remain... this is "A/C ripple". Similarly when the powersupply converts 12v to 50v it is converted to A/C and then back to D/C, which creates ripple once more.

Grim0013 · Post by **Grim0013** » Fri Jan 30, 2009 4:17 pm

So, from what's been said before, would it be safe to say that when it comes to the PS and rail caps, more capacitance is always better? I noticed Stipud was looking at using 5600uf caps for the power supply. (vs 2200uf stock) That's a pretty big increase. And there is no downside to using "bigger" caps?

Oh, and is 30x35mm the absolute biggest size for raid caps on an MS amp? Looks like there isn't enough room to expand in thickness or height. Is this correct?

dgoodhue · Post by **dgoodhue** » Fri Jan 30, 2009 4:24 pm

If you do need rail caps, you might want to try contact Phoenix Gold and buying them from them. I ran into the same issue with replacing the rail caps on a M100.

I have somewhat decent list of caps part numbers (in addition to the supply caps) I ordered to replace some of the smaller caps for M25, M50, M100

thedeal7235 · Post by **thedeal7235** » Fri Jan 30, 2009 5:21 pm

Grim0013 wrote:To start things off, I am having a hell of a time finding the proper caps for my MS-2125s. The smaller PS ones seem easy enough to source, but the big rail caps are a bitch. It seems 10,000uf @ 50V is the "biggest" 30x35mm cap available, and on top of that, nobody seems to stock them. Of note, I saw that my 2125TA has 6800uf rail caps, so I imagine going a little smaller doesn't kill you.

Currently, the closest to spec that I have been able to find (in stock) is 8200uf and 85*.
http://search.digikey.com/scripts/DkSea ... e=P6938-ND

Not what I'd like, but it should work. My question however, is how much of an impact do you guys think using these caps would impart?

Also, about the PS caps, they are 2200uf, 16V is I remember right. Is there any benefit to using larger caps there? like these:
http://search.digikey.com/scripts/DkSea ... ?Selection

These are all 16x20-25mm, 10,000 Hours @ 105*, 16V, ranging from 2700-4700uf.

Thanks,
Brad

go to www.newark.com, they ship out of south carolina, and youd probably see the rail caps in 3 days(ur in virginia -right?- illinois capacitor part number70k9460-it is 10000Uf @ 50 volts, 35mm by 35mm, if those arent the right size, then keep lookin ghtere, illinois caps are good caps, they came stock for the rail caps in the V1 zx series 450 amps by pg-and this cap has 3000hr life-hope this helps?!