Capacitors

[Mr.Curwen]

Which caps do you usually use on your 'Wrecks? I've seen a lot of folks use Orange Drops, some Mallory 150's.

Are cap brands critical in the Express? More than in some other amps?

Anyone tried Vitamin T's or other oil filled caps?

[johnny riff]

Hey,I'm far from the top dog around here.but I've used the OD6ps's,mallory pvc's and mallory 150's with great results.It's a matter of your tonal taste.
Johnny

[Structo]

Something I learned early on in my amp hobby was that the term "Orange Drop" is a rather vague term.

Sprague used to make the orange drop film caps and now there are a few different manufacturers of them, the primary one in the states is SB Electronics.
There are roughly 4 different types of orange drops depending on which dielectric is used.

There are the film caps and then there are the metalized film caps.

There are polypropylene and polyester mainly but a few variations of both.
There are pressed type that look a bit flatter and the rolled type that are cylindrical.

There are radial leaded ones and axial leaded ones.

The ones that most are familiar with is the PS series.
But these can be polyester or polypropylene.

The series with a voltage rating of 200 thru 1000VDC are polyester and the ones that are rated at 1600 and 2000VDC are polypropylene.

Most agree that the 6PS series which are rated for 600VDC are a good cap to use in a tube amp.

Mallory 150 caps are polyester as well but a lot of people prefer the PS orange drops to the Mallory's.

http://www.sbelectronics.com/productlines.htm

[gearhead]

The caps that Ken Fischer used in the best documented builds are the current Mallory (Cornell-Dublier) PVC series of caps. Take a look at the BOM in the Express Documents section of Trainwreck Files.

[billyz]

I have used several type caps for coupling and tone. I did use the Mojo Vitamin T caps. They sounded good but, I have had several fail and will not use them any more. I have had very good results with older Vitamin Q sprague and other brands, just use NOS. No failures at all. I also tried some Rusky caps and they were the worst, bad tone and failed very quickly. Mallory, SBE, CDE all good. Have not tried the SoZo's yet, when I run out of what I have, I will try the new Blue Molded Sozo's. If anyone else had tried them I would love a review.

[PlinytheWelder]

I'm going to be using Russian PIO caps along with some Black Gate electrolytics as cathode bypass. Metal films in the front end for noise, Silicon Carbide diodes as rectifiers, also for noise. A distributed star grounding scheme like Allyn's 80W beast. Plus Dana's power scaling board.

Yeah, it's not traditional Express, but it's my amp and I want to play a bit!

[Structo]

I want to build a test bed amp that I can try different types of caps for bypass as well as coupling.
It will have spring clips where the caps go for quick installation.

I am particularly interested in trying some different film caps for bypassing, instead of the typical electrolytic.

Also I want to try some LED's for bypassing preamp tubes.
Apparently this is being done in tube Hi Fi amps.