MS-2125 cap replacement

Grim0013 · Post by **Grim0013** » Sun Jan 25, 2009 4:15 pm

Hey guys. At least one of my 2125s needs it's caps replaced, as I see electrolyte on the PCB. I am gonna go ahead and do the other original 2125 as well. Should I also do the 2125TA? I don't see any evidence of issues, but should I just play it safe? And speaking of the TA, I noticed that the larger caps on the 2125TA are 6800uf, while on the original 2125s they are 10,000uf. Seemed sort of odd.

Anyway, could someone tell me what caps I should order for a 2125? Would like to be certain I use the right stuff, as this will be my first time.

Thanks,
Brad

marko · Post by **marko** » Sun Jan 25, 2009 10:48 pm

the TA should be ok, that looks to have had a cap upgrade already.

Post by **stipud** » Mon Jan 26, 2009 7:05 am

I will be redoing my MPS2500 as well...

I've got it down to...
http://search.digikey.com/scripts/DkSea ... 93-1804-ND
and
http://search.digikey.com/scripts/DkSea ... e=P6667-ND

Only problem is that my factory rail caps are 40v rated, so I need to confirm first that the rail voltage is <= 35v.

Unfortunately I haven't found any 40v or higher replacements that would fit AND offer >= 10000uf like the stock part. If I can't get anything suitable, then I will probably just stick with the input caps.

marko · Post by **marko** » Mon Jan 26, 2009 8:37 am

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...

Grim0013 · Post by **Grim0013** » Mon Jan 26, 2009 10:24 am

After a taking a look, here's what I have in there right now

2x2125
2200uf/16v
10,000uf/50V

1x2125TA
2200uf/16v
6800uf/50V

Post by **stipud** » Mon Jan 26, 2009 11:10 am

Man, those rail caps must've been expensive back in the day. I've found it's damn near impossible to get anything that matches all of their specs.

It's strange because the input caps have come a long way since then.

At 50v 105* the best I can find is 6800uF

http://search.digikey.com/scripts/DkSea ... e=P6687-ND

Or at 85* you can get 10000uF
http://search.digikey.com/scripts/DkSea ... e=P6940-ND

Edit: here's another option but I am unsure of the brand
http://search.digikey.com/scripts/DkSea ... 65-2897-ND

Regardless, you don't need to do the rail caps unless you are super anal like I am (though lack of selection is driving me towards just doing the input caps as well).

Grim0013 · Post by **Grim0013** » Mon Jan 26, 2009 11:39 am

stipud wrote: At 50v 105* the best I can find is 6800uF
http://search.digikey.com/scripts/DkSea ... e=P6687-ND

Well, I guess that explains the 6800ufs in my 2125TA. I wonder what the impact is from using them?

Post by **mhyde71** » Mon Jan 26, 2009 12:28 pm

hey guys... I will do what I can to help/assist with what caps you all should get and stuff... But I am distracted at work right now... I will see what I can do... and if anything maybe we put an order together for the canadians to save a lil on shipping - But i do also know that digikey will ship to canada. do what I can if it is needed??

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.

Post by **stipud** » Mon Jan 26, 2009 12:28 pm

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.

Post by **stipud** » Mon Jan 26, 2009 12:41 pm

Hmm... min order 125

http://ca.mouser.com/Search/ProductDeta ... ao5n2gI%3d
http://ca.mouser.com/Search/ProductDeta ... QX8JNvw%3d

Post by **stipud** » Mon Jan 26, 2009 2:20 pm

Woot! The MPS2500 has 28v rails, so I am good to go with the 35v caps.

This amp better sound like God's breath when I'm done

Grim0013 · Post by **Grim0013** » Tue Jan 27, 2009 3:33 pm

How about these?

http://www.newark.com/illinois-capacito ... dp/70K9460

Kinda spendy, at $6.63 per. May be others on that site that will work as well, but I wasn't quite certain what I needed to look for.

thedeal7235 · Post by **thedeal7235** » Tue Jan 27, 2009 4:22 pm

i think i used those same exact ones for the rail caps on my zx450, so thats the right price and pg did use those on the zx V1s illinois caps for the rail voltage, but if its power caps these are not the right ones(these are snap -in); i like illinois caps, but nichicon(spell right) usually, imho, are the best and last longer, but the zx600.2 i have here fs, its rail caps were about to literally bursts-peaked like a mountain when i obtained it, and i ripped those out ASAP!!!! onlyother amp ive ever seen rail caps needing to be replaced is my zx450, i think rail caps are more rare than the power input caps-you want to look for radial lead, usually7.5mm spacing, if its power caps, usually at 16v, now rail caps ive seen them at 35, 50 v, etc, and they are called snap-in

thedeal7235 · Post by **thedeal7235** » Tue Jan 27, 2009 4:23 pm

and forgive me guys, if u covered this, im not gonna lie, im a terrible reader, so if this has been covered, my bad!!!:(