Fender Blue Molded/Blob Caps - why type of capacitor?

Messages
334
Just wondering what type of capacitor those are.

They aren't ceramic disc caps, nor electrolytic, don't think they are silver mica?

Just wondering - I have one as my bright cap right now until I get a ceramic disc replacement.
 

Trout

Member
Messages
7,550
Blue Blobs like the ones on the right here?



ITW marked on them?
Plain Jane film caps,, likely purchased low cost surplus like most parts in Fender amps in the old days.
 
Messages
334
Thanks - yes - I put a 47pf Blue Blob on my volume pot as a Bright Cap.

So thats a "Film Cap?" Hmm, how does that sound compared to a ceramic disc? I just ordered a ceramic disc and push-pull pot early today.
 

Trout

Member
Messages
7,550
Thanks - yes - I put a 47pf Blue Blob on my volume pot as a Bright Cap.

So thats a "Film Cap?" Hmm, how does that sound compared to a ceramic disc? I just ordered a ceramic disc and push-pull pot early today.

I think you will find 101 opinions on the sound of any cap.

I read someplace that film caps over 100pf are not desirable but no real data on why.

I typically use Silver Mica caps in that position. I have used polystyrene film for bright caps and honestly loved the sound of them,, but they are a bit delicate and all the ones I had were also fairly heat sensitive.

Experiment,, you might like ceramic,, you may prefer the film or heck,, the mica caps are cheap as well. I typically buy CDE brand from Mouser.
47pf 500V
 

J M Fahey

Member
Messages
2,940
Polystyrene is a film cap .

Take a looooong strip of any plastic film you like, (polyester, polycarbonate, polystyrene, teflon, mylar, you name it), metallize both sides, roll it tightly, connect terminals and for finish and protection dip it in yet another plastic, usually some kind of Epoxy or in the old days, put it inside a die and inject plastic (that's why they were called "molded").

Some Hi Fi audiophiles swear by "handmade ones", "pure silver foil", etc. but truth is that thanks God today all are very good and made in NASA type machines such as this one:



Leo would have murdered to have the high quality, low cost parts we have today.
 






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