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    PIO Break In Strategies

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    heyraz

    Posts : 58
    Join date : 2011-10-26

    PIO Break In Strategies

    Post by heyraz on Tue Nov 22, 2011 3:42 am

    I just replaced the MPK output coupling caps of my Sound Valves VTP-101 preamp with PIO Sprague Vitamin Q's. First impressions were not stellar as expected but did begin to show slight improvement after 30 minutes. I realize there is a long break in period of anywhere from 30 to 300 hours and wonder if there is a better way.
    Do I leave the preamp on for 2 weeks?
    Do I leave the preamp on with a source playing (FM)?
    Do I leave the preamp on with a source playing and the amp on? Amp on Softly?
    Or do I just go about business as usual and wait a few months?
    I plan on using the Vitamin Q's in my ST-70 Project as well.
    Thanks guys. Rich

    Bob Latino
    Admin

    Posts : 2377
    Join date : 2008-11-26
    Location : Massachusetts

    Re: PIO Break In Strategies

    Post by Bob Latino on Tue Nov 22, 2011 8:55 am

    Hi Rich,

    You don't need the amp on to break in the preamp. What I would do is have some source playing through the preamp - either an FM tuner as you suggested or a CD player set on repeat. My feeling is that the FM tuner would be a better idea rather than put a week or two's wear and tear on your CD player.

    I have used Vitamin Q caps before as coupling caps in an ST-70. They were OK but maybe a little "soft" sounding to me with a slight top end roll-off. That does not mean that they will sound like that in your preamp application though.

    Bob

    Jim McShane

    Posts : 154
    Join date : 2011-10-19
    Location : South Suburban Chicago

    Re: PIO Break In Strategies

    Post by Jim McShane on Wed Nov 23, 2011 6:30 pm

    Or do I just go about business as usual and wait a few months?

    Yes!! Why put hours on your tubes unnecessarily, drive up your electric bill, and heat up your room (unless it's winter!)? Just play some music and enjoy the process. It's not like it's going to be unbearable to listen to until they're broken in, they just may not be at the absolute best for a while.

    BTW, I agree with Bob Latino - I find Vit-Qs to be a bit soft. I much prefer the K40s, I even use them in one position in my Citation II amp kits.


    Bob Latino
    Admin

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    Join date : 2008-11-26
    Location : Massachusetts

    Re: PIO Break In Strategies

    Post by Bob Latino on Wed Nov 23, 2011 8:08 pm

    I agree with Jim ... the K-40Y Russian PIO (paper in oil) caps give very accurate and smooth response one broken in 100 to 200 hours. The K40-Y's were made to very high standards for the Russian military during the cold war. The Russians also made a K42 version and a few other models. The K42's were a later version and (IMHO) do not sound as good as the earlier K40-Y's. The Russians also made some nice sounding Teflon caps. Unfortunately the Russian Teflon caps are very large for their voltage rating and in many cases will not fit into an area.

    I had one customer who liked the K40-Y's so much in his VTA ST-120 kit amp that he bought an extra set of four and installed them into a very expensive Audio Research amp. The K-40Y's replaced the stock caps that came with his Audio Research amp. I honestly don't remember what type of cap his Audio Research originally came with ?

    Bob

    heyraz

    Posts : 58
    Join date : 2011-10-26

    Re: PIO Break In Strategies

    Post by heyraz on Wed Nov 23, 2011 9:25 pm

    I've also heard raves about the Russian K40-y's and even more about the FT-3's. Unfortunately for my preamp (which has the Real Estate to try something big), I've never seen either in the value I need (2.2uf). That's why I went for a more conventional PIO, and Vitamin Q's seemed as good as any of the others I've read about. They were also a reasonably priced way for me to try PIO caps.
    Do you think there is any value in me bypassing my 2.0 uf Vitamin Q's with a 0.1uf or 0.001uf FT-3 or K40-Y? I tried bypassing the original 2.2uf MPK's with 0.1uf Vit Q's before and really didn't notice any difference at all. Nothing jumped out at me as though my windows just got cleaned, and when I removed them or went back and forth (they were on alligator clips)I really couldn't tell you one from the other.
    Now the ST-70 is a different story as I haven't constructed it yet. Do you have K40-Y's available in the 2 values I need (0.22uf and 0.1uf) and if so, how much are they? Rich

    tubes4hifi
    Admin

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    Join date : 2008-11-30

    Re: PIO Break In Strategies

    Post by tubes4hifi on Wed Nov 23, 2011 11:56 pm

    Jensen makes some PIO caps in 2.2uF, check them out at PartsConnexion http://www.partsconnexion.com/capacitor_film_jensen_aluminum.html
    the aluminum ones are the cheapest at about $43 each. Copper foil starts around $95 each.
    Mundorf silver-oil caps are really nice starting around $65 each in your value.
    I haven't heard Obbligato Film Oil Capacitors but they are very inexpensive around $5.50 each.
    You can find hundreds of various PIOs on ebay listing, just search for PIO capacitor.

    jjones3318

    Posts : 57
    Join date : 2011-04-05
    Location : Boulder, CO

    Re: PIO Break In Strategies

    Post by jjones3318 on Thu Nov 24, 2011 2:32 am

    You can get Russian 2.2uf K75-10 in 250V or 500V versions - both are available on ePay right now. I've read several instances of people liking the K75-10 better than the K40Y-9. I have four, but haven't tried them yet.


    foodog

    Posts : 2
    Join date : 2012-12-20

    PIO Dark/Veiled?

    Post by foodog on Thu Dec 20, 2012 4:16 am

    I see Bob mentions ~100 hour break-in -- I have some K40Y-9s in both my amps and just tried some in an Aikido PAS3 amp board. The sound is *very* dark, veiled and sounds like 500Hz to 2000 is totally reduced. I let them run for 48 hours, but no change. Is this normal and should I just wait more time -- it's really not he best thing to listen to and I've confirmed it is definitely these caps.

    BTW, the Aikido board in the PAS is amazing!

    Bob Latino
    Admin

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    Join date : 2008-11-26
    Location : Massachusetts

    Re: PIO Break In Strategies

    Post by Bob Latino on Thu Dec 20, 2012 10:18 am

    Certain types of capacitors in different applications may or may not work out well. The Russian K40-Y's seem to work out very well as main coupling capacitors in power amps. I don't know how they would work out in a completely different type of application like a preamp circuit? They may not work out well in an Aikido PAS-3 preamp board ?

    Bob

    foodog

    Posts : 2
    Join date : 2012-12-20

    Re: PIO Break In Strategies

    Post by foodog on Fri Dec 21, 2012 2:32 am

    Bob: Thanks, that makes sense, something I didn't know before. The Audyn caps that came with the Aikido board were so amazing, I figured I'd try a couple others to see if they would change something in a good way. Going back to the Audyn here shortly -- I'm sure someone (you'all) have already tested this and found the Audyn are best. Needless to say, the Aikido upgrade is so mind-blowing, I'll be ordering more kits, etc. here shortly.

    I just bypassed the Balance/Blend knobs (highly recommended), and that sounds even better, so I figure I need a good quality Volume pot now.

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: PIO Break In Strategies

    Post by PeterCapo on Fri Dec 21, 2012 1:03 pm

    I used K40Y-9 as coupling caps on the PC board for my PAS rebuild. Considering the kinds of comments you sometimes hear about the original PAS circuit, it really sounds surprisingly good. I am sure much of the credit also goes to Roy’s power supply cap board that I also included in the rebuild.

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