47pf Cap in Express PI

[Ron Worley]

OK, dumb question time.... I obviously need to study more...

The small blue (Mica??) 47pf cap on the back side of the Phase Inverter:

-What's it's function
-Any ideas on the make / model used in Francesca? Trying to complete a BOM.. which I will share with the board for review if nothing else.

Ron

[jaysg]

What's it's function

Suppresses high frequency oscillations. It's considered good practice on anything Marshallesque or otherwise hi gain.

[Noel Grassy]

Dude, pardon me, Ron, I used to see those little caps at a surplus joint I frequented and now they don't seem to exist anymore. I think they're just ceramic caps under a nice dollop of epoxy. They might have been labeled ITT, IIRC. Sorry I can't be of more help, NG

[Ron Worley]

Which explains why I haven't seen it before.... I have been working on Fenders since I started messing with amps!

Thanks Jay!

Ron

[Ron Worley]

Thanks NG..... When you look at the Mouser and Allied catalogs, there are just sooooo many ceramic caps shown...

Anybody have a solid recommendation here from their builds?? Allynmey would know, but he's tied up at NAMM at this point.

Ron (or dude, whatever works)...

[lastwinj]

panasonic ceramic from digikey. work perfectly

germ

[Noel Grassy]

Ron, I may have found them on Allied's cat page #1459. This is a CKE HV capacitor with all the capabilities you desire in a cap. Good luck, NG

[Ron Worley]

NG-

I have the 2008 catalog, that page is shrink tubing.....

Can you spare the P/N of said cap???

Thanks,

Ron

[paulruby]

http://www.mouser.com/catalog/632/705.pdf

http://www.mouser.com/Search/ProductDet ... nk4g%3d%3d

[Ron Worley]

Thanks Paul, I assume that a 500V value will be adequate for this purpose.

Ron

[paulster]

I think you want a 1KV. I remember reading an article before on cap performance and the ceramics changed markedly between voltage ratings.

The cap in Francesca is 1KV.

[Ron Worley]

Roger that, thanks for the Help!!

Ron