High voltage capacitors for a tube preamp: What exact type do you recommend ?

[rantony]

Hello guys,

I'm building a tube preamp running at high voltage (in the 330V range). I need 0.1uF and 0.047uF caps. I'm looking for capacitors similar to those huge orange-red caps that you find in the vintage amps. Should I go with polyester or polypropylene capacitors ? I found many expressions on the Web:

Metallized Film Capacitor
Radial Film Disc Capacitors
High Voltage Poly Film
Metallized Polypropylene
Polypropylene Film
Film and Foil Polypropylene
Metal-Foil Polypropylene Film
Polyester Film
Metallized Polyester Film

What should I exactly target ? Any preferable brand(s) ? Sprague, Mallory ? If possible, please give me exact part numbers on Mouser or Digi-Key...

Thanks !

[d95err]

Looks like you're thinking about Sprague "Orange Drop" capacitors. Just get any kind of capacitor that has adequate voltage rating and a size that will fit in your build. Get cheap ones, it doesn't matter much for the tone. Capacitor tone differences are VERY subtle (most people would hear no difference at all in a proper blind test), so don't bother with mojo vintage type caps.

Once you're done with your build and feel like wasting some money, you could try replacing some caps with other cap types and see if you can hear any difference.

[defaced]

There are three common series of the Sprague orange drops and they're not the same.  The 225P, 715P and 716P.  225P are polyester, the 715P and 716P are polypropylene.  I use both (225P and 715P), and can't hear a difference between the two in the high gain circuits I build.  I suggest doing your own tests.  Caps are cheap and there is not substitute for personal experience, not even reading the 100s of threads on cap type spread all around the internet.   

[rantony]

OK ,thank you guys for your input !

I have two preamps to build. I think I will build one with polyester caps and the other with polypropylene and see if I can notice a difference...

[defaced]

Unless the circuits are 100% identical (all parts measured and matched within some crazy tolerance (1% maybe), same layout, same iron, same eveything), you're wasting your time on a test that won't tell you anything about the caps.  You'll hear differences in the circuit before you'll hear any difference in the caps (if they truly exist).

[rantony]

Ok, then I will follow d95err's advice and simply get cheap caps. And maybe I will make tests later...