How do you know if you need new caps?

Bchester6 · Post by **Bchester6** » Tue Jan 04, 2011 9:23 am

I have a ZX475ti and I know at some point in time it will need the caps replaced but how do you tell when it's time? Is there an audible difference in the sound? at approx. 10 years of use?

tonym · Post by **tonym** » Tue Jan 04, 2011 2:36 pm

they will buldge or leak...you can slide a piece of paper under them and see if its wet when you pull it out...or just look at the board ...

Post by **Eric D** » Tue Jan 04, 2011 4:53 pm

There is a good chance that amp WON'T ever need new caps.

I am not going to say this is for certain, but I have yet to find a Ti amp with bad caps in it, which was not abused (typically overheated badly).

When the Ti line came out, PG used better caps. The new ones will probably fail someday, but not like the old ones, and maybe not even in our lifetimes.

Bchester6 · Post by **Bchester6** » Tue Jan 04, 2011 5:45 pm

thats really good to hear.

12voltjunky · Post by **12voltjunky** » Tue Jan 04, 2011 5:49 pm

temperature will definitely play a major role in the life of a capacitor.

Eric D wrote:There is a good chance that amp WON'T ever need new caps.

I am not going to say this is for certain, but I have yet to find a Ti amp with bad caps in it, which was not abused (typically overheated badly).

When the Ti line came out, PG used better caps. The new ones will probably fail someday, but not like the old ones, and maybe not even in our lifetimes.

Eric, do you think that the Ti line being newer than the zx line has much to do with it?
or do you believe the caps used in the Ti line are, in fact, that much better?
i find this very interesting.

valeks1 · Post by **valeks1** » Wed Jan 05, 2011 1:13 am

Caps on ZX line better then on TI

valeks1 · Post by **valeks1** » Wed Jan 05, 2011 1:25 am

Bchester6 wrote:I have a ZX475ti and I know at some point in time it will need the caps replaced but how do you tell when it's time? Is there an audible difference in the sound? at approx. 10 years of use?

If you wait to long can be to late.

Post by **Eric D** » Wed Jan 05, 2011 8:43 am

I think it boils down to the caps on the Ti being better.

For all I know the Ti caps are a cheaper part, but the manufacturer (can't remember if it is Nichicon or not on Ti amps) must have gotten the formula correct.

I have Rockford amps from the 80's, and have fixed RF amps that old, never once have I seen a leaking cap. The batch of caps used on MS, M, ZX, and ZPA amps (maybe others I forgot as well) are just plain junk caps.

What is really wild to me is leaking caps were a huge issue in the computer industry a few years back. But those would split and leak on the top. These PG amps with caps leaking on the bottom is quite odd.

I even have worked on electronics from the 70's with no leaking caps.

Many of the MSTA amps used Nichicon caps with the same appearance and same model line. We will have to see if those start leaking. Keep in mind a lot of MSTA amps are getting around 10 years old now, and we know old MS or M amps have been leaking within a 10 year span.

Post by **stipud** » Wed Jan 05, 2011 11:41 am

valeks1 wrote:Caps on ZX line better then on TI

We have several occurrences of these leaking out the bottom as well. Hmm...

Maybe the "worse" caps are overall more reliable? Or maybe Ti amps have yet to reach the age where they start leaking en masse?

I used to only recommend cap changing on M and MS amps but lately the ZPA and ZX seem to need it more and more often.

Post by **Eric D** » Wed Jan 05, 2011 1:48 pm

Every ZX amp I have owned has needed new caps. Replacing ZX caps is how I got my start in fixing amps in the first place. ZX250 with hole through the board, Reactor with cap fire, and I think another ZX500 with a cap fire.

I also have a new in box, never used ZX amp, and you can see the fluid leaking around the caps. I won't change them as I am keeping that amp original for collecting purposes, but it is pretty sad a never powered amp has failing caps in it.

Pillow · Post by **Pillow** » Wed Jan 05, 2011 6:07 pm

>Every ZX amp I have owned has needed new caps.<

I have done maybe 8 cap replacements on PG amps. All but one ZX needed its caps done... I did them anyway just as a precaution though.

Leaky sum bishes!

crosleykings · Post by **crosleykings** » Fri Jan 14, 2011 12:03 am

I'd like to piggyback onto this thread with a follow up question.

I came across a Sapphire sa1.4x at a pawn shop. I've been looking for a good budget 4-channel, and the price was right. It was tested and worked fine in front of me, but now i'm considering re-capping the thing before i install it. It has (4)35v 1000uF and (4)16v 2200uF caps<--- at least those are the big ones. Should I look to replace any of the smaller caps while i'm in there?

I also noticed it is filled with BA 4560 op-amps (12 of them), and was wondering if this particular amp could benefit from upgraded op-amps, or am I getting in over my head without access to an O-scope?

Thanks in advance!

Post by **Eric D** » Fri Jan 14, 2011 4:07 am

Please post a photo of the 2,200uF caps. They might not need to be replaced, but chances are they are the same as the rest and do need to be replaced.

Op-amps don't really make an audible difference in a car audio amplifier (IMO), so replacing them is not cost effective. Putting the money towards a better amp, or better speakers will get you more return on your investment.

crosleykings · Post by **crosleykings** » Fri Jan 14, 2011 10:33 am

Eric D wrote:Please post a photo of the 2,200uF caps. They might not need to be replaced, but chances are they are the same as the rest and do need to be replaced.

Op-amps don't really make an audible difference in a car audio amplifier (IMO), so replacing them is not cost effective. Putting the money towards a better amp, or better speakers will get you more return on your investment.

Sure, here's some pics I took last night:
The 2,200uF caps

The 1000uF caps

Thanks for your advice on the op-amps. I'm not too worried about nicer speakers or a nicer amp, as this is just my DD. It's been a project to build the cheapest car i can (doing all the labor myself) and still have something I enjoy driving. Here's the car if anyone is interested:

http://forums.acuralegend.org/saved-scr ... 14183.html

Thanks for your help!

Also, should I replace them with the same values, or try to source larger capacity caps? I can get them locally.

Post by **Eric D** » Fri Jan 14, 2011 5:57 pm

I am pretty sure those caps are not the ones which fail so often. However, I am not 100% certain of this and if your amp died in a week because you took my advice I would feel pretty bad about it.

You can try the other methods of checking like using a piece of paper slid under them to see if any fluid is picked up. There are probably some other tests you can perform as well.

crosleykings · Post by **crosleykings** » Mon Jan 17, 2011 2:11 pm

Eric D wrote:I am pretty sure those caps are not the ones which fail so often. However, I am not 100% certain of this and if your amp died in a week because you took my advice I would feel pretty bad about it.

You can try the other methods of checking like using a piece of paper slid under them to see if any fluid is picked up. There are probably some other tests you can perform as well.

Thanks for advise. If my amp died in a week, I wouldn't be too surprised and certainly wouldn't fault you at all. It was 20$ from a pawn shop!

(they also have a ppi pc450 for 80$!)

Nothing leaking from the caps using the paper trick, so I think I may just take my chances.

Thanks again.

How do you know if you need new caps?

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