To poly or not to polyester?

[tony dB]

Seen the recent topics about condensators pass by...
Just went to order some polyesters from a supplier who's tech himself and very into trannies, valves, vintage, hifi (sorry for swearing), etc...

He told my i better get poly(-propy?somethingelse) as he threw away his entire stock of polyesters a while ago. I told him i wasn't looking for the best sounding caps, but the ones that where listed by Jakob, as i have a lot of faith in his concept and knowledge.

Without wanting to become victime of the salesman in this person (what i don't sell or have stocked is never good), is it possible to put say other caps as replacement for polyestertypes. I also heard a story about Black Gates (graphite inside??) and so on...

Still, i do not want my G9/SSLcomps/API's compromised whatsoever :evil:

DIY is already difficult enough for a poor musician as myself, aaarrghh, plz help me out here

Cheers, i'm heading for some serious :guinness: :guinness: :guinness:
and :guinness: are on me btw.

Tony (with headache coming)

 

[NewYorkDave]

Polyesters are fine. Stop worrying.

 

[tony dB]

that's the thing Dave!
Polyesters are not what they seem to sell around here :sad:

 

[NewYorkDave]

I'm sorry. I had a hard time understanding the original message.

Polypropylenes are fine, too. They're actually a little better, maybe not enough to really notice. If that's what you can get, use 'em.

 

[DrFrankencopter]

Generally, a polypropylene cap will be better sounding than a polyester, but either will be a better choice than an electrolytic. In the case of the API/SSLcomp, you're using electro's for coupling anyways, so there's no point in worrying there, just choose good electros (panasonic FC's, Nichicon, Black Gate, whatever as long as its low ESR and low dialectric absorbtion).

Where I think it can make a difference between polyester and polypropylene is in tube gear in the coupling cap application. Generally mass produced gear uses polyester caps for cost (and space) savings over polypropylene, but in a new construction you can often use polyprops for a cleaner sound. I replaced the polyesters in my Peavey VMP-2 preamp with solen polyprops and it made a noticeable difference to me (sounds less cloudy now).

If you've got polyesters, use-em...if not, see if you can get polyprops that fit (if not, just buy polyesters, and don't wory about it). That's what I do....

Cheers,

Kris

 

[radiance]

Someone commented on my ssl clone saying I should not use MKT caps for power decoupling of the opamps and VCA's.
His argument was that MKT's are good for audio but not for power decoupling of opamps and VCA's. He also said that I should use sybatit caps instead.
Can someone comment on this?
I don't know much about this subject.
Thanks.

 

[radiance]

[quote author="buttachunk"]
i don't know what those are...

polyesters are fantastic for PSU decoupling.[/quote]

Me neither.

Also I asked this person the clarify his comments but I'm still waiting for him to answer.

 

[mcs]

[quote author="radiance"]He also said that I should use sybatit caps instead.[/quote]
Siemens Sibatit capacitors perhaps? They are ceramic capacitors meant for decoupling in digital circuits - not for audio. If you ask the hifi people, they will tell you never to use ceramic caps with "bad" dielectrics (such as Sibatit caps) for audio use, and to use MKT caps instead...

I don't see why you shouldn't use MKT caps. Just get stackfoil caps or "extended foil" caps - not wound caps. Wound caps will have a lot of inductance, and won't be effective for HF decoupling.

Best regards,

Mikkel C. Simonsen

 

[CJ]

Sometimes ceramics are better than poly's.
Guitar amps come to mind.
my 3 cents. (inflation)

I had a girlfriend named Poly once. Or was it Ester?

 

[mcs]

[quote author="CJ"]Sometimes ceramics are better than poly's.
Guitar amps come to mind.
my 3 cents. (inflation)[/quote]
Yes, "good" ceramics are fine. The low value ceramic caps (<10n) are good caps, or can be at least. But high value ceramic caps are not very good. The values vary a lot with the temperature and with the voltage accross them for instance.

Best regards,

Mikkel C. Simonsen

 

[cayocosta]

Sybatit caps, het! Jumpbat, kissmisseff.

 

[hodad]

[quote author="CJ"]
I had a girlfriend named Poly once. Or was it Ester? [/quote]

This reminds me of a very bad joke I made up while doing laundry in a slightly altered state.

Q: What do you get when you cross Lassie with a joint?






A: a pot 'n' collie blend.


Ummmm.....it was funny at the time.

tom