Petp Capacitors-one Of The Best?

[Praudio]

An other opinion ; Audio Asylum tubes DIY:


In Reply to: Re: Large Value PIO caps that click ... posted by Derick on May 28, 2002 at 02:54:37:


Dielectric types of some russian caps:
(russian letters alliterated in latin)
K31, SSG, SGM, KSO - mica, some types with silver - good
K40 - PIO - very good
MBGxx, KBG-xx, OMBG - PIO
K42, MBM, BM-x - paper (w/o oil ??)
K70, K71 - Polystyren ("polystirol") - good
K72, FT - teflon ("ftoroplast") - THE BEST
K73 - Polythelene Teraphthalate film ("lavsan") - poor
K75 - combined Paper+Film (Polythelene Teraphthalate??, with or w/o oil??)
K76 - Laquer film
K78 - Polypropilen
Question:
What kind of dielectric used in caps marked as "MMK" (not russian :-))
Thanks.

Regards.
Alex.

[audiojoy]

HI PR AUDIO

always good to get feedback from others
but the post you have quoted also says at the start of it

"Here is a short summary I copied from somewhere"
and ends with

"It doesn't matter how you stir
the pot, Bu-ls-it in always equals Bu-lsh-t out!! "

"from somewhere" ??? what does that mean, and therefore how meaningful is that. The final line is not very inspiring either. I felt the rest of the thread comments were also a little dubious in their aims.

Here is the full thread from which you quoted

http://www.audioasylum.com/cgi/t.mpl?f=tubediy&m=140839

Also I do have to take note of the comment regarding the quality of the K73. I believe they sound at least ok but never 'poor'!!!!


I have no problems with people getting findings different to mine but please lets have more personal creditable objectivity!

[jameshillj]

AJ,
There was some mention in the AudioAsylum replies about having enough voltage across the caps.

With the valve amps, this isn't a problem, but in other application, it may be the reason for such mixed results - would this be reasonable, or more of that damn BS!?

[piero7]

I have the maximum respect about other opinions, but reading some comments I say: just try these PETP capacitors on you tube preamp. They costs few $ and give them a chance. My opinion after a trial with other caps is: they are excellent!

[audiojoy]

JH

that is an interesting point , my answer to that is not sure,

[jameshillj]

Looks like a bit of fun when they show up.

I'll try them in the speaker Xovers (lo volts), the SS amp cap bipass (42 v) and send a few to some valve amp guys.

No doubt they'll take ages to breakin - Ah well!

[piero7]

Originally posted by jameshillj
Looks like a bit of fun when they show up.

I'll try them in the speaker Xovers (lo volts), the SS amp cap bipass (42 v) and send a few to some valve amp guys.

No doubt they'll take ages to breakin - Ah well!

we'll wait for your speaker test with these caps

[jameshillj]

Yeah, when they eventually show up - getting impatient which is ridiculous considering they have to travel to the other end of the world.
My system uses an F3 amp to drive a full ranger and has been optomised for detail, so should be able to hear some differences. There's some spares and will bang some of 'em into the headamp, too.

[piero7]

still waiting your trial ...

[jameshillj]

Okay, Folks
The Caps arrived yesterday and exchanged the 4.7uF PP AmpOhm for the Rooshin' 4.7uF/63volt K73-16 skinny metal cased things as the bipass cap to the main F3 amp's output cap (Siemens Sikorel [41550] 22,000/40v) and it has 21volts dc across it. The amp is wired throughout with 0.7mm 4 - 9s silver and drives my Coral betta8's (without only minor cone resonance now) from 250Hz up from the Lorrantz 12" base.
[Alternative "monitors" are the AKG701 (rewired!) from same amp - for when you want to get really picky - good for working on NOS cd players!]

With only about 15 hours on them, these things are quite remarkable - they definitely have more detail than the AmpOhm PPs and remind me a bit of the Teflon/Tin ones but don't seem to have as much "edge" - I've got the amp cranked up quite a lot with that DiMeola/McLaughlin "Friday Night..." cd - the audience noise is a bit annoying, but the balance of the music is rather good.
Before I had the K2 sampler going ("This is K2 HD Sound - Various Artists") to see what the lower mids would come out like - the AmpOhms are rather good here (IMO, naturally!) - I think there is a bit more detail in the K73 caps, but the base is a bit "fatter" - quite attractive actually, but not as clean.

How, you are going to say, can a 4.7uf cap on a 22,000uF possibly effect the base notes?!!
Well, it goes like this - I haven't a clue, but it does!!

Imagination? Quite possibly, but consistent phantom results and I'll stick by them!

Remember, the F3 is a current gain amp, not the usual voltage device, and so the choke is now across the mid driver and the caps are across the base - back to front!

Next thing will be to replace the caps across the 12" base driver (6dB/oct Xover) - currently a mixture of Clarity Cap SA, AmpOhms, and a Janzen 1uF Superior Z, plus the obligatory blue 15nF 1837 cap (waste of space, but ...!)
This maybe give a contradictory result as the speakers generally only require about 1 - 2 watts (100+ mA) but we'll see.

So far, these things are quite a big surprise - rather astonishing actually, and if they continue to develop over the next week, as i expect .....

Thank you Audiojoy for passing on the good news.

Will report about the Xover results - I have enough for a complete K73 replacement - might connect them to a 10volt (ac)transformer for a day or so, to hasten the "break-in" period.