Maybe polypropilene in oil is an option .
You might get them at Angela's .
http://www.angela.com/

"rod keys" schreef in bericht
...
Gents,

The last time I built speaker cross-overs was MANY moons ago. I used
"oil filled" caps about 20 mfd that were meant for timing circuits in
old vacuum tube instruments. (I know, 20 mfd = rather low crossover
frequency). But I'm not able to find such caps any more!

The problem is three fold. 1) Rather high mfd value, 2) Need to be
non-polarized, 3) Need to sound "clean" (no extra internal
resustance, inductance or "chunkie" electrolytic action). The old
trick of electrolytics wired "back to back" works - kinda - but they
sound like electrolytics ... (read, how to make a perfectly good tube
amp sound like a solid state amp).

What's available for good cross-over caps today? Are motor starter caps
true oil fills or some cock-eyed variation on electrolytics?

And what's with PCB content in old oil caps? I must admit that I find
PCB paranoia more hype than science, but it seems like it's driven many
good components out of the market. Is this why real oil fills have
disappeared?

Rod

Hi RATs!

PCBs are not vitamins

Oil caps without PCBs are so old you can buy them surplus ...

Happy Ears!
Al

PS Motor run are not electrolytics


Alan J. Marcy
Phoenix, AZ

PWC/mystic/Earhead

Hi !
http://www.arrakis.es/~igapop/capacitors.htm scroll down
to Siemens Oil - these are oil, no pcb and not so old ( May 92 )
I belive that there is another German company ( not Siemens )
that still makes them.
Best regards,

--
Igor
http://www.arrakis.es/~igapop



PCBs are not vitamins

Oil caps without PCBs are so old you can buy them surplus ...

Happy Ears!
Al

PS Motor run are not electrolytics


Alan J. Marcy
Phoenix, AZ

PWC/mystic/Earhead

I believe GE makes these still. Check through the Allied, Newark,
Electro-Sonic, etc. catalogues and you are sure to find what you want
eventually.

rod keys wrote:

Gents,

The last time I built speaker cross-overs was MANY moons ago. I used
"oil filled" caps about 20 mfd that were meant for timing circuits in
old vacuum tube instruments. (I know, 20 mfd = rather low crossover
frequency). But I'm not able to find such caps any more!

The problem is three fold. 1) Rather high mfd value, 2) Need to be
non-polarized, 3) Need to sound "clean" (no extra internal
resustance, inductance or "chunkie" electrolytic action). The old
trick of electrolytics wired "back to back" works - kinda - but they
sound like electrolytics ... (read, how to make a perfectly good tube
amp sound like a solid state amp).

What's available for good cross-over caps today? Are motor starter caps
true oil fills or some cock-eyed variation on electrolytics?

And what's with PCB content in old oil caps? I must admit that I find
PCB paranoia more hype than science, but it seems like it's driven many
good components out of the market. Is this why real oil fills have
disappeared?

Rod

non-pcb caps show up on ebay a lot. I've gotten a few there.
There's quite a selection of pp foil and pp metalized foil caps
available on the tube parts sites, also. Many of these are 250 v
versions for speaker crossovers.

http://www.madisound.com/

http://www.partsexpress.com/webpage....&WebPage_ID=69

Angela and Handmade has large value Solens, also.

Bob Hedberg

rod keys wrote:

Gents,

The last time I built speaker cross-overs was MANY moons ago. I used
"oil filled" caps about 20 mfd that were meant for timing circuits in
old vacuum tube instruments. (I know, 20 mfd = rather low crossover
frequency). But I'm not able to find such caps any more!

The problem is three fold. 1) Rather high mfd value, 2) Need to be
non-polarized, 3) Need to sound "clean" (no extra internal
resustance, inductance or "chunkie" electrolytic action). The old
trick of electrolytics wired "back to back" works - kinda - but they
sound like electrolytics ... (read, how to make a perfectly good tube
amp sound like a solid state amp).

What's available for good cross-over caps today? Are motor starter caps
true oil fills or some cock-eyed variation on electrolytics?

And what's with PCB content in old oil caps? I must admit that I find
PCB paranoia more hype than science, but it seems like it's driven many
good components out of the market. Is this why real oil fills have
disappeared?

Rod

Bob H.

Just grab that plate in one hand, the chassis in the other,
and FEEL the power of tube audio!!!
(not literally, of course, just kidding. DON'T DO THAT!)

Bob Hedberg wrote in
:

non-pcb caps show up on ebay a lot. I've gotten a few there.
There's quite a selection of pp foil and pp metalized foil caps
available on the tube parts sites, also. Many of these are 250 v
versions for speaker crossovers.


250 Volts! WOW! That comes to over 7800 watts at 8 ohms!

r



http://www.madisound.com/

http://www.partsexpress.com/webpage....&WebPage_ID=69

Angela and Handmade has large value Solens, also.

Bob Hedberg

rod keys wrote:

Gents,

The last time I built speaker cross-overs was MANY moons ago. I used
"oil filled" caps about 20 mfd that were meant for timing circuits in
old vacuum tube instruments. (I know, 20 mfd = rather low crossover
frequency). But I'm not able to find such caps any more!

The problem is three fold. 1) Rather high mfd value, 2) Need to be
non-polarized, 3) Need to sound "clean" (no extra internal
resustance, inductance or "chunkie" electrolytic action). The old
trick of electrolytics wired "back to back" works - kinda - but they
sound like electrolytics ... (read, how to make a perfectly good tube
amp sound like a solid state amp).

What's available for good cross-over caps today? Are motor starter caps
true oil fills or some cock-eyed variation on electrolytics?

And what's with PCB content in old oil caps? I must admit that I find
PCB paranoia more hype than science, but it seems like it's driven many
good components out of the market. Is this why real oil fills have
disappeared?

Rod

Bob H.

Just grab that plate in one hand, the chassis in the other,
and FEEL the power of tube audio!!!
(not literally, of course, just kidding. DON'T DO THAT!)





--
"Any sufficiently advanced technology is indistinguishable from
magic."

Arthur C. Clarke (1917 - ), "Technology and the Future"

I use WW2 vintage, 600 to 1000V, hermetically sealed, caps WITH PCBs for the
most natural sound. I've built a half dozen pairs of speakers, and it really
works for me. Out board XOVRs are a good idea, and size limitations,
therefore, aren't a problem. If I don't have the exact value, I parallel to
get as close as possible. GE Pyranol, Micamold, Sangamo, etc.,,,,,,, in
otherwords the usual suspects. Vitamin E is fine, but prices are quite high,
and to my ears, there're no better than Pyranol, and so on. I wish the non
PCB oil caps were sealed as well as the old stuff, because I'd more confident
using them upside down in power supplies, (they tend to leak at the termals,
oozing past rubber gaskets). Good luck with your speakers! Robert T.
Live and let live!