 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
71.178.164.153
Has anyone tried
Seems to be a type of PIO I've never seen or heard of. Very high voltage tolerance and very inexpensive.
Follow Ups:
Is it true that these PIOs need time to "open up", somewhat like the tubes? If so, how long would it take?
Which pio caps did you buy,the k40s or MBGs,k42s?
Thanks Mike. Yes, the K40Y-9s. I put a set in the Eicos and they sounded just fabulous right out of the box. What a difference.
I have never played with these capacitors, which is why I started the thread. Perhaps Mike Samra or Twysted can help. I don't necessarily subscribe to the idea that tubes per se need time to open up. Capacitors are more likely to need break-in than tubes, IMO.
According to my Russian Cap cataloge:
K75-59
КОНДЕНСАТОРЫ КОМБИНИРОВАННЫЕ
С МЕТАЛЛИЗИРОВАННЫМИ ОБКЛАДКАМИ
____ PAPER – METALLIZED FILM CAPACITORS
Предназначены для работы в импульсных
режимах.
Конструкция: в цилиндрических корпусах из
полимерных материалов.
Designed to operate in pulse mode.
Design: cylindrical housing made of
polymeric materials.
L 25+5 25+5 D
Æ 0.8
Æ
From the Ukrianian HiFi mafia: K75 - combined Paper+Film (Polythelene Teraphthalate??, with or w/o oil??)
Hope that help:))
33dot33rpm
I have a phobia about PIO caps.
Sounds like they are more like motor run capacitors (metallized film + oil, I think) than like conventional PIOs.
Lew
Hermetically sealed pio caps seldom leak..This is the reason they are sealed so it doesn't happen.Moisture is what causes most all caps to fail.
when they made my Jensen PIOs or my VTV silver foil PIOs that leaked all over the inside of my amplifier?
I'm just joking; I can see that the Russian PIOs that you like are very well made, and I have hopes they will hold up over the long haul.
He must have tried to date Hans Jensen's daughter and he didn't like it so he kicked him out..Argh argh argh.
Hey Lew, I've tried them, along with most Ruskie types. They aren't the worst caps out there and reasonable value at the price but I'm pretty sure that they won't be up to your standard.
I couldn't remember their sound but just realised that I have a copy of some notes here at work ... "Strong mids (but less honky than K73) otherwise fairly balanced. Detailed, slightly accentuated treble."
Hope this helps
Naz
Thanks, Naz.
Sounds like they should be "good enough" for use as bypass capacitors around electrolytic capacitors in the power supply for Beveridge direct-drive amplifiers, unless they get leaky at high voltages. Eight 450V electrolytics are connected in series across 3200V. I am thinking of bypassing each individual lytic in the string.
The K75s have very rich, fast, and dynamic mids...way superior in all ways to ANY electrolytic. I like them for power supply bypass duties. Yes, as others have posted, they can have a little high bandwidth edge to them, most noticeably in coupling duties (not so much with power supplies). I use them as final power supply caps, in larger values of course, as well as MBGO caps. Often I will use a high value MBGO in my power supplies, bypassed by a smaller K75. I've bread boarded supplies comparing electrolytics, MGBOs, Solen types, and motor runs. The best sound I could come up with, after MUCH experimentation, was the MBGO bypassed with a K75.
I've recently used 250V (50hz) 2.2uf K75-10 caps as parafeed caps in my 6n6p line stage (bypassed with .1uf SSG silver and micas), with excellent results. BTW, the way the Russians label caps, the voltage can be DC or AC rated. If it's AC rated, it will say 50hz, right after the voltage, so my 250V 50hz caps are good to about 350VDC (conservative). Yours look to be good to just their 630V rating, but that is more than the electrolytics.
Also the Rooskies are notorious for their conservative ratings, as most mil spec stuff was rated for use in severe duty environments, (high G, high vibration, extreme temperatures, and altitudes), so I doubt they will be stressed more than your 450V electrolytics.
I do admit that I never use components for more than their rated specs, but every time I've seen posts by folks that have, they seem to always report a very big tolerance for abuse, with Russian components in general. If I was you, I'd take the added precaution of wrapping the metal case of the K75s with several layers of electrical tape. After all, the series connection divides the voltage, across the string, but case to ground is a whole other story, 3200V gets into pretty scary territory.
twystd
Thanks for your thoughtful analysis and for the tip about insulating the cases. Good point.
Worth a try for the money.
Also, FWIW Mikey asked what my favourite Cap was but deleted the post. Since I went to the trouble of typing an answer but got side-tracked before submitting I thought I'd post it anyway. My answer:-
"I am VERY impressed with the latest V-Cap CuTF. These may be super expensive but almost impossible to fault and even better than the V-Cap TFTF and OIMP which I had previously used.
I've liked quite a few other caps for their particular strengths but few seem to be balanced overall. Of the Ruskies, Teflon and Silver Mica edge out PIO IMO, though you might throw a K40 into the mix to tame an edgy system.
Would like to try Duelund one day"
Naz
The KBGs and the OMBGs are fantastic but the Sonic Plats are my favorite of the commercial caps..They sound like a paper in oil mixed with a teflon but what I have really found is putting paper in oil caps where B+ is present and putting a film cap or teflon where B+ is not present.The best cap I have ever heard are the Russian silver mica but you have to stack them as they only come in .1uf.THey are so neutral that you really aren't listening to a cap.
I cant justify spending the big busks on the latest and greatest boutique caps after I found those puppies.
twystd
"This the first pair of Mc30s I did with this cap arrangement..You see a soniccap plat on the input,a single K40y going into the phase inverter,but on the most critical stage you see the silver micas,which are going from the phase inverter to the voltage amp.From the voltage to the driver we have gudeman pios.Three months ago I changed out the last caps to SSGs also but I only stacked two of the .13s which put us right where we wanted to be.I have to find the photos.
You may have to do what I did on my Acoustat servos as I converted those 6K6gs..Your amp uses 36KD6s and I as I remember,the filaments may be in parallel. Rodger Madjewski designed them and they are very nice amps but getting the tubes is like pulling teeth.
I've only tried them in values > 1uF and they are no KGB-MN. But they are better than other K75 types I have tried, just a little sibilant edge. They are so inexpensive I would give them a try. They have been available on ebay for years in larger values, I don't know how available they have been <1uF.
Matt
I have a bunch of the K40 PIOs below coming this week for couplers.
I've always wondered if the green K75s were as good. As you say, at this price, it warrants some testing.
The K40s never sounded at good as the FT-3 teflons to me. But it's cheap enough to try and find what works in your circuit, that's really the best guide.
Matt
Lew
The pio caps will perform well depending on where they are used..They need DC voltage across the dielectric to perform their best.
Post a Followup:
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
