Need to find particular cap for Bugera 1990 Tube Head

[itek]

Hey guys I'm new to recapping and have been troubleshooting this Bugera 1990 tube head and found a bad cap. It is 350v 330uf 22mmx50mm. It only says "LT" and "Decon" on it, and I can't find an exact match at digikey, mouser, or newark. Once I start searching they have options like ripple current and ESR, which I don't know if those make a difference or not. The closest I can find is here:
http://search.digikey.com/scripts/Dk...name=P14031-ND
Will this work? Please excuse my lack of knowledge
Thanks!

[TheLaw]

Re: Need to find particular cap for Bugera 1990 Tube Head

Can you take a picture of the entire circuit board and point out where it was located on the board? Low-ESR is typically better for audio. Ripple current is essentially how heavy duty it is.

You want ESR to be lower and ripple current to be higher...in most applications.

Also measure the diameter of the capacitor and how long/tall it can be to fit. You don't want to have this thing shipeed and then not fit.

[TheLaw]

Re: Need to find particular cap for Bugera 1990 Tube Head

Oh I found the datasheet to the Decon LT series. The ripple current should be 1.4A or greater. They are just general purpose capacitors so you don't really have to worry about ESR, although lower-ESR = better quality (most of the time).

We won't be able to find the best replacement until you measure it up.

[itek]

Re: Need to find particular cap for Bugera 1990 Tube Head

OK here are some more crappy pics sorry bout the quality i need to get a good camera in here,,, The bad cap is on the right, but i'm thinking the one on the left is bad too, so I was just gonna order two of them and test the other when I get a chance. They both have the same text on them, why are the tops different?

They both measure 22mm wide and 50mm tall, they are pretty cramped so I don't think we can go wider but can go a little taller maybe 60mm, thanks for you help man!

[Th3_uN1Qu3]

Re: Need to find particular cap for Bugera 1990 Tube Head

The tops are different because the one on the right has overheated and the label melted and the black plastic top fell off. This most likely happened due to overvoltage, so a 400 volt replacement wouldn't hurt.

[Scenic]

Re: Need to find particular cap for Bugera 1990 Tube Head

if you can squeeze 25mm dia caps in there..

http://search.digikey.com/scripts/Dk...name=P11772-ND

[itek]

Re: Need to find particular cap for Bugera 1990 Tube Head

I don't know there is only ~3mm between them, unless I can tilt them...

[itek]

Re: Need to find particular cap for Bugera 1990 Tube Head

So I tested the cap that looks good and it test 320-321uf and .06-.09 ESR

[TheLaw]

Re: Need to find particular cap for Bugera 1990 Tube Head

So I tested the cap that looks good and it test 320-321uf and .06-.09 ESR

You have a cap meter? Nice!

It's normal to have a capacitance less than printed. It degrades over time.

[TheLaw]

Re: Need to find particular cap for Bugera 1990 Tube Head

Now that I'm looking around, those specs in the Decon's datasheet seem like they might be a bit overrated or something. I'm having a very hard time finding a 22mm cap in that capacitance/voltage rated at 105C and with >1.4A ripple...hmmph.

I'd try to squeeze 25mm caps in there, if I were you....

[itek]

Re: Need to find particular cap for Bugera 1990 Tube Head

so 22mm->25mm=1.5mm increase on each side * 2 = 3mm which is my gap exactly -- I think i'll barely be able to squeeze them in
i'm gonna go ahead and order the ones Scenic recommended,
Thanks guys!!!

[TheLaw]

Re: Need to find particular cap for Bugera 1990 Tube Head

Yes please do. It's quite an upgrade from anything you can get in 22mm...somehow...

[itek]

Re: Need to find particular cap for Bugera 1990 Tube Head

I got the caps and got em installed, the amp makes sound again!!! They just barely fit, they are tilted a small amount as seen in the photo, will that make a difference? I noticed the old ones were sealed against the board with some silicone or something and these how have a small gap on one side. Hopefully this is OK? Thanks again for all you help

[Scenic]

Re: Need to find particular cap for Bugera 1990 Tube Head

shouldn't be a problem.
the silicone like stuff is usually to hold them in place during manufacturing (before they get soldered in)

[itek]

Re: Need to find particular cap for Bugera 1990 Tube Head

Thanks Scenic you have really helped!! Till Next Time..