Fender capacitors

[Paul P]

When building a new version of an old Fender amp we're faced
with replacing the types of capacitors used then with ones
available today. So far I've decided to use CDE Mallory 150's
(metallized polyester) in the tone stacks and to replace the
big blues ones in Brown amps, and Mallory 160 series (metallized
polyester) to replace the coupling caps. For the low value
ceramic disks I'll use CDE silver micas.

I'm wondering what to use to replace high value ceramic disks
Fender used in a few places, like 0.01uf and 0.02uf. Should I
go with silver micas or can I use metallized polyesters ?

I guess I'm really asking is why did Fender use ceramic discs
in places that it could have used something else ? Cost ?

--
Edit : I just looked up the prices and a .02uf mica cap goes
for 43$ !. A .01 is 13$...
--

Paul P

[Angelo Skouras]

Paul my friend.

Don’t spend so much and don’t tire your head. Capacitors have only capacity and voltage ratings. Don’t care of the type of the capacitors. They are all the same. Capacitor imperfections make differences in sound that cannot be understood by human’s ear. Someone may thing that I should put butter and honey on by breakfast’s bread, not in my ears, but I have never understood any sound difference when changing the type of the capacitor.

The prices you mention are unbelievable. Capacitors are not any kind of high technology… they are only two electrodes with an insulator between! I have never spent more than 0.50€ for a Cap!

Safety: Never confuse the polarity of electrolytic capacitors. When I connect an electrolytic C I always remove the fuse of the house, and then turn power on with no mains supply in my laboratory’s room. Then I put the fuse back restoring the mains, and go at laboratory’s door watching for explosions. Don’t blind an eye or two for a F thing like that! Electrolytics make very dangerous explosions.

[Liam]

I'd beg to differ with Angelo here, and will state categorically that all capacitors are not the same. A capacitor has inductance and resistance, just the same as an inductor has capacitance and resistance. Trouble with replacing ceramics is that to my ears only ceramics sound like ceramics. Silver mica definitely sounds brighter and more modern, especially in the tone circuit.

For the cost of a few capacitors, buy mylar and metallized polyester, try both in the circuit and see what sounds best to you. If you can find any NOS ceramics try them as well. You can't recreate 50s, 60s or 70s amps (I'm reliably informed no two sounded the same anyway), but if you try things and keep your ears open you will find something you like, and you'll learn a lot at the same time.

(Those prices sound insane, I'm going to check my stocks!)

[MWJB]

Silver micas are fine in tone stacks, bright caps on volume controls etc., but I wouldn't waste your money using them in tremolos etc.