yet another which cap is best for the money question

[photo_marc]

As sit and ponder my cap choices I have heard that the auricap Metallized Polypropylene is a very good choice.

With the budget I have, I am considering the GE 41L series metalized polypropylene. I have compered these to solen, Kimber and Multicap and have been very please. They can be purchased at allied electronics for $2.00 for a 1uF 400VDC or 1/5 the cost of the Auricap

If my project goal is to get a decent amp I can get up and running with plenty of time to tweek later, does any one have a reason that the GE 41L is an issue? Is the Auricap realy that much better?
Marc

[Sherman]

Originally posted by photo_marc
As sit and ponder my cap choices I have heard that the auricap Metallized Polypropylene is a very good choice.

With the budget I have, I am considering the GE 41L series metalized polypropylene. I have compered these to solen, Kimber and Multicap and have been very please. They can be purchased at allied electronics for $2.00 for a 1uF 400VDC or 1/5 the cost of the Auricap

If my project goal is to get a decent amp I can get up and running with plenty of time to tweek later, does any one have a reason that the GE 41L is an issue? Is the Auricap realy that much better?
Marc

This is a great question and I'm looking forward to reading other's opinions. I'll give mine for what it is worth.

I haven't used the GE caps so I can't comment on them directly. I have used Auricaps. I put Auricaps in my SE KT88 amps and I like the results. Like you I wondered if the Auricap would be noticeably better than a less expensive cap but didn't want to muck around in my new main amps. When I built an EL84 amp I figured this would be a good time to test things.

I first put Auricaps in the amp and listened carefully and had my teenage sons listen as their ears can still hear sounds above 15KHz! I then put in a pair of Dayton caps. One son said he heard a difference but that it wasn't necessarily worse. I heard no difference at all.

Next we popped in a pair of Solens and repeated the listening test. None of us heard any difference between the Daytons and the Solens.

We switched back to the Auricaps and now all three of us thought we could hear a difference. None of us thought the difference was something we would ever lose any sleep over.

Next back to the Solens and now we all thought the difference was there. Then to the Daytons, no difference from the Solens and back to Auricaps from the Daytons and there it was again but also once again not a big difference.

Bottom line- very unscientific test and very hard or impossible to describe the difference in words. I would have been happy with any of those 3 caps in the amp. I didn't do any measurements with my scope or distortion meter, it was all subjective listening.

[andyjevans]

Russian K72 ex-military teflon caps will smoke most others - available on ebay up to values of .1uF (sometimes but rarely 2.2uF). They are big and very very good - if you have space use them in multiples. There are smaller 200v ones as well, and these are easier to make up values like 1uf with.

There are some Russion K40 paper in oils as well, which are smaller and pretty good. I wouldn't bother with the other Russian caps unless you can find any silver mica ones.

[dsavitsk]

I did a comparison of a bunch of cheap caps, though it sadly did not include either the Auricaps or the GEs. My findings, like Shermans, were that most caps are pretty decent, though I do think some are better than others. You can read my findings at http://www.ecp.cc/cap-notes.html

The short answer, though, is that I would use something cheap to start (the GE caps sound like a good option) and upgrade if you think you need to.

None of us heard any difference between the Daytons and the Solens.

I believe that Solen makes the Dayton caps, so they should be the same.

[rdf]

Voodoo disclaimer: The following opinions are for entertainment purposes only. No double-blind panel tests were harmed in the selection process, the results stem from ~ a year's daily casual listening to an amp in progress.

My current fave for coupling with across high differential voltages is the "mica + silver SSG-3" cap sold on Ebay by ranutek. It's a .2uF, 0.3% tolerance 350 volt silver mica. Like Sherman the choice came from trying a few types in a scratch-built EL84SE, including PIO K40Y9's, Auricap, Solen, Orange Drops, Philips NOS Polycarbonates (a junkbox part) and one or two others. To my ear they topped all others in this circuit, your mileage may vary.
For the first stage bias cap which runs at a very low differential voltage I prefered another part from the junk box, an old TRW film/foil polystyrene. It appears (pls see above disclaimer) that the 'best' cap might be contingent on operating conditions.