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Power Supply caps for Mesa Boogie

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8/1/2004 6:34 PM

Power Supply caps for Mesa Boogie

I finally got around to pulling the chassis on my Boogie MKIII and quickly found the source of the snaping sound I heard everytime I powered it on. It seems that two of the 4 big 220 uf @300VDC caps were not securly soldered onto the PCB. In one case the lead had broken at the cap, in the other the lead was not soldered in (dry hole). It's a wonder it worked at all. It hummed at idle but wasn't really all that bad. I guess that's a kind of testimonial to the power supplies in these things. By the way, all 4 of these caps come before a choke, after which there's even more filtering going on (3X30uF @ 500 VDC)

Anyway, I'm looking for the best, reasonably priced caps to replace them with. I figured that I'd use the Sprauge Atoms but can't find a source for them in this size. Are the F&T's any good? The Powerlytics? What else can you suggest?

It also has some other ones that are hard to find, like 3300@16 (Radial lead), 30@500 etc.

What's a good source for these things?

Thanks

Howard Chandler

8/1/2004 6:46 PM

Use any cap rated 105C out of the Mouser catalog. High temp caps give lower ESR because of glycol based electrolyte, as well as longer life.

Don't be fooled by designer caps. Electrolytics are pretty much all the same at the same temp rating. Best caps IMO tend to be those sourced out of asian factories having names ending in "con" such as Nichicon, Chemicon, Xicon and so on. Sounds unscientific I know. But this rule seems to hold up well.

8/1/2004 10:22 PM
Howard	****Use any cap rated 105C out of the Mouser catalog. Easier said than done. I've checked Mouser and elsewhere but I can't seem to locate the values I need in that temp range. I might have to break down and call Mesa.

8/1/2004 10:54 PM

I would get them from Mesa. I have a .22+ which I changed out the caps to Sprague ATOMs which are decent enough caps but they don't fit as well and it seems the sound changed also. Plus, I tried a bit higher value caps at first because I could not get the same exact value, and that also sounded worse. I've never bought from them but IIRC, you need a serial no. from the amp so you may want to have that on hand when you call.

8/1/2004 11:01 PM
Carl Gigun	The panasonic TSHA caps are 105c and have a good rep. They're about five dollars each for the value you need from digikey. -Carl

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