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Russian K40y9 input coupling caps - first impressiond

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Posted on February 11, 2017 at 04:23:35
KanedaK
Audiophile

Posts: 733
Location: Brussels
Joined: April 27, 2010
I replaced two MKP Arcotronics with Russian PIO K40y9 0,033uF as coupling caps in my Trends TA10.1 amplifier.
The main goal being to create a 96Hz high-pass filter (see my other post).
But man! The PIO caps are not even burned-in at all, and I understand how dull, lifeless and boring the original Arcotronics MKP were!
These PIO k40 have so much energy in the midrange, it digs up details and brings so much life and light without sounding harsh or unnatural, it's FABULOUS and they cost me a couple euros each! It sounds just SOOOO good! I'm a happy camper!!! :)

I'll see how it transforms after some burn-in time, but I'm already fantasizing of replacing all coupling caps in my system with K40y9. (But maybe it would be too much of a good thing).

Anyways, STRONGLY recommended.

 

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RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 04:27:24
KanedaK
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Posts: 733
Location: Brussels
Joined: April 27, 2010



The original caps (well, it was a MODDED Trends to start with)

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 04:28:37
KanedaK
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Posts: 733
Location: Brussels
Joined: April 27, 2010



The "new" PIO k40y9 :)

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 04:31:14
KanedaK
Audiophile

Posts: 733
Location: Brussels
Joined: April 27, 2010



Close up

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 10:05:28
Tweaker456
Audiophile

Posts: 2701
Location: No. Cal
Joined: January 19, 2012
Good for you. Another good thing is what looks like some nice thick input output wires, untwisted. Aluminum gets a lot of respect. The one experience I have with aluminum caps was excellent. Very natural. I say replace the .01's with the same cap and the electrolytics with Elna Silmic II'S as long as the voltage is correct. If I were you I wouldn't worry about the too much of a good thing thing unless you think you don't deserve it for some past bad deeds. Just my humble opinion. T456 EDIT: 2/12/17 While the K40 is well though of and it's a good thing you have something you like a lot it is tin that gets the respect I was thinking of as being very natural sounding. It's my impression from what people think who have a lot of experience that tin is second to CU.
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 13:11:32
Lew
Audiophile

Posts: 8935
Location: Bethesda, Maryland
Joined: December 11, 2000
See those beige-colored capacitors marked ".22J100"? Those are 100V/0.22uF. If they are in the signal path (as it appears they are), replace them, too, for another big improvement. I had a few of that type in an electronic crossover. Replacing them with teflon capacitors was one of the most obviously beneficial tweaks I have ever done to anything. Truly night and day. They may be polyester or polycarbonate; not good. At best, they are metallized polypropylene. Polystyrenes are available in small enough size to fit there, and they would be a big upgrade too. (My preference: teflon>polystyrene>polypropylene. Film and foil over metallized film.

By the way, I do think that replacing all the capacitors with K40s would be too much of a good thing. K40s won't fit, anyway.

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 13:48:43
Tweaker456
Audiophile

Posts: 2701
Location: No. Cal
Joined: January 19, 2012
Sure looks like the 200v K40 .01's would likely fit. The idea that foil caps sound better than metallized is very likely not necessiarly true. Maybe the "best" foil would sound better than the "best" metallized but there are some pretty horifying sounding foil caps out there. As to overdoing a good thing I still think it very unlikely in the case of the K40's which you already like alot. Aluminum caps have a very good reputation for sounding very natural. If the caps leaned toward the clinical than maybe I'd worry? A lot cheaper than teflon caps also. Do consider upgrading the input resistors. As always, one has to listen for themselves. T456
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

Length of K40y9 .01uf, posted on February 11, 2017 at 14:15:21
Tweaker456
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Posts: 2701
Location: No. Cal
Joined: January 19, 2012
Think you could make that fit?
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

Happy for you, posted on February 11, 2017 at 19:18:23
madisonears
Audiophile

Posts: 1201
Location: midwest
Joined: September 6, 2006
Nice that it worked so well, and nice of you to share the results with us. Part of what you are hearing (clarity, dynamics) is due to the cap, but another part is probably due to reducing low freq's where they're not wanted. One quick experiment you should consider is playing some music or test freq's without the bass amp, just so you get an idea of how low your mids are going. It's always comforting to hear reality enforcing theory.

I strongly recommend taking a long pause before making any other mods. Let this mod settle down before you make an evaluation. Listen to lots of music and get to know it again. The sound will definitely change. I know the temptation to "fix" everything is strong. More of a good thing is sometimes too much, and too many of any one type of component will impart a definite voice to your system, and then you'll be lost without a reference.

There are better caps, although perhaps not better value. Anyone who says metalized caps sound better than true film and foil probably does not have a legitimate range of experience, and copper ALWAYS sounds better than aluminum.

Peace,
Tom E
berate is 8 and benign is 9

 

forgot to mention, posted on February 11, 2017 at 20:36:32
madisonears
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Posts: 1201
Location: midwest
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Here is another tweak to try. I see from your detailed photo that the caps are supported by their leads. They are stout and strong enough to hold them up, but they are not rigid enough to immobilize them. Caps are sensitive to vibration, even inside an enclosure, and should be secured and damped. Put something under or around them to damp vibration: any foam or piece of insulation will work, or just a piece of heavy tape stuck to them. It will probably improve clarity, even though it might seem at first to dull the sound somewhat. That's a good thing: you're not really hearing detail, but distortion caused by vibration. You might be able to hear further INTO the music, instead of just a surface brightness.

Peace,
Tom E
berate is 8 and benign is 9

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 20:42:32
Tweaker456
Audiophile

Posts: 2701
Location: No. Cal
Joined: January 19, 2012
It has been postulated by Tom E, unless I am misinterpreting, that the K40 caps are filtering "unwanted" bass frequencies. KanedaK, do you hear a rolled off bass from the K40's compared to the Arcotronics. This comment, on the surface, seems bizarre to me. That just changing the cap would get rid of "unwanted" low frequencies. What is an unwanted low frequency? Once again I may be missing something. If I am maybe you can ask Tom E for an explanation. All I saw in your post is the one cap change. So even if the cap got rid of "unwanted" low frequencies it would still be because of the cap. Not unlikely that a better cap would improve the bass. T456
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 11, 2017 at 20:43:20
jad
Audiophile

Posts: 148
Joined: August 23, 2002
I too have used teflon caps in my Marchand XM44 and they were a great improvement over the WIMA's I had in previously. Since then I replaced the teflons with K40Y's and they are head and shoulders over the teflons.

 

RE: forgot to mention, posted on February 12, 2017 at 02:50:20
KanedaK
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Posts: 733
Location: Brussels
Joined: April 27, 2010
Yes it bothered me that, due to available space and lead spacing, i could not secure the caps tightly against the board (the Arcotronic caps were also floating in the air, btw). That said, the leads are really thick and strong.
I thought about wrapping the caps tightly in Teflon tape but I should have done it prior to soldering them :( also part of me didn't want to hide the beautiful metal body :/ wrapping things up in teflon tape looks tweaky as hell ^^
I also thought about compressing a piece of sorbothane under each cap, but I'm afraid the sorbothane might react with the board material or with the cap's body, I don't see it as an endlessly stable material. I'll figure something out.

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 12, 2017 at 02:58:30
KanedaK
Audiophile

Posts: 733
Location: Brussels
Joined: April 27, 2010
Tweaked, in this case i voluntarily changed the value of the input caps to create a 96Hz high-pass filter. This little 8 watts amplifier drives the midrange and treble horns in my system. See my other post about it ;)
The decision to use Russian PIO caps came second, browsing the bay for caps with the right value, and reading so much good things about these. I must say I'm impressed so far!

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 12, 2017 at 03:08:26
KanedaK
Audiophile

Posts: 733
Location: Brussels
Joined: April 27, 2010
But yes, I will have to let things settle down.
The sound is still changing, I can actually hear it change: I already réajusted the relative volume of this amp with the volume of the bass amp, twice. Ever so slightly, but I had to adjust it twice: first lower it, then put it slightly higher again, then lower it again.
The burn-in of these caps seems to be quite rocky and roller-coasterish but the nice qualities remain throughout. I'm sure it will turn out fine (I remember, when I fully recapped my preamp with SilmicII caps, the sound became so dull after a few hours that I was almost sure I broke something, and it took another 100 hours to open up completely again... hard days ^^)

By the way, I had previously swapped the Nippon Chemicon reservoir caps with bigger (2200uF) Nichicon FG caps and it was a step back. I left them is for months but somehow the sound was sluggish and flat. I put the old caps back in and miracle, good sound was back!

 

Is that a passive or active line stage?, posted on February 12, 2017 at 05:02:32
Michael Samra
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Contributor
  Since:
June 24, 2005
The k40ys are fantastic caps and nobody loves them more than I do.Since you are using this as a high pass filter,some of that exceptional clarity is due to the fact that you aren't passing lower frequencies.Without a doubt the k40y is a better sounding cap,but you really have compare it to another .033 cap to be fair.

"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

 

RE: forgot to mention, posted on February 12, 2017 at 05:50:18
bcowen
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Contributor
  Since:
January 1, 2017
Some clear RTV silicone caulk does nicely in an application like this -- just add a small amount between the cap and the board and then let it cure fully. If you get a small squeeze tube (rather than a big tube that goes in a caulk gun), it's much easier to control the amount and positioning to keep from getting it all over the place.

 

RE: forgot to mention, posted on February 12, 2017 at 11:44:20
Tweaker456
Audiophile

Posts: 2701
Location: No. Cal
Joined: January 19, 2012
IMO Mortite sounds better than silicone. Might give it a try. T456
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

RE: Is that a passive or active line stage?, posted on February 12, 2017 at 16:34:54
KanedaK
Audiophile

Posts: 733
Location: Brussels
Joined: April 27, 2010
Michael, i guess nobody posted more about k40 caps than you did :) and I fully understand why you like them so much!

This ain't a line stage. It's a small 2x 8watts tripath amplifier. Actually a heavily modded Trends TA10.1 ;)

 

What "teflons"?, posted on February 12, 2017 at 18:03:04
Lew
Audiophile

Posts: 8935
Location: Bethesda, Maryland
Joined: December 11, 2000
Not all teflon capacitors are created equal. Funnily enough, I tried the K40Ys and found them to be like most other "good" PIO capacitors; they make everything sound "good", but they lose some of the dynamic contrasts that you hear in a live performance. (My opinion, at least.)

Anyway, I doubt that K40Y's would fit in the allotted space where we see those ".22J100" capacitors. Polystyrene film types would also be a good choice. From the photo, it is not obvious to me that the new K40Ys are acting as couplers, but I take the word of the OP for that.

 

What's an "aluminum" capacitor?, posted on February 12, 2017 at 18:14:23
Lew
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Posts: 8935
Location: Bethesda, Maryland
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Do you refer to a capacitor using aluminum foil or metallized film? IME, in a film and foil capacitor, tin sounds better than alu, and copper foil sounds better than both. Unfortunately, the latter type tend to be so expensive that most of us cannot afford to use them consistently.

Really good sounding metallized film capacitors include the Auricap XO and the Dynamicap, IMO.

 

Woops, my mistake. I stand corrected, posted on February 12, 2017 at 19:55:42
Tweaker456
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Yo Lew, it is tin that gets the respect that I was talking about. In this case the OP likes the also well respected aluminum PIO cap so for him that's a good thing. In my one experience with comparing a tin cap an aluminum cap the tin won hands down. I was actually thinking about tin and confused it with aluminum in this case. They ARE both shiny? Won't happen again. T456
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

RE: What "teflons"?, posted on February 13, 2017 at 01:51:34
KanedaK
Audiophile

Posts: 733
Location: Brussels
Joined: April 27, 2010
I'm actually satisfied with how it all sounds now - and I want to let these new caps settle in before changing anything else.
But it's true I could later change those small 0,22 caps. What about silver mica?

 

No need to apologize..., posted on February 13, 2017 at 07:52:47
Lew
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Posts: 8935
Location: Bethesda, Maryland
Joined: December 11, 2000
I was just wondering what you meant. I think (but do not know for sure) that metallized film capacitors are made on a base of aluminum foil. Only the two brands of metallized film caps I named are allowed in my gear, on the odd occasion. Usually when I need a large value that fits in a small space or when I don't want to spend the dough on a film and foil equivalent.

 

0.22uF is a rather large value for silver mica,..., posted on February 13, 2017 at 07:55:44
Lew
Audiophile

Posts: 8935
Location: Bethesda, Maryland
Joined: December 11, 2000
but you may be able to find them in that amorphous plastic casing, as used in many phono RIAA correction circuits. The Russian SSGs are way too large and only available up to 0.13uF/350V. If space is at a premium, the Auricap XO or Dynamicap would almost certainly sound better than the ones you'd replace.

 

RE: What "teflons"?, posted on February 13, 2017 at 10:45:53
Tweaker456
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Posts: 2701
Location: No. Cal
Joined: January 19, 2012
I'd be looking for a tin foil cap that would fit in the .22 space. Maybe Michael S. can hip you to something that would work. T456
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

Holy Smokes What about the Dayton DFFC?, posted on February 13, 2017 at 11:13:11
Tweaker456
Audiophile

Posts: 2701
Location: No. Cal
Joined: January 19, 2012
I read the Dayton Audio DFFC caps are tin foil PP and are dirt cheap. Almost literally dirt cheap. People are raving about them. Tin foil is almost universally respected. A while back when I was looking into tin foil caps this one avoided my radar, assuming it's not brand new. This cap, if it sounds near as good as the much more expensive tin foil caps could spark a revolution. I say try an make them fit somehow. T456
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."

- Q, 2365

 

RE: Russian K40y9 input coupling caps - first impressiond, posted on February 13, 2017 at 18:44:54
madisonears
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Posts: 1201
Location: midwest
Joined: September 6, 2006
It wasn't a postulation. If you took care to read the OP, you'd know that. In addition, the photo clearly showed a .033uF cap. What low frequencies do you think a cap of that value could pass?

Regards,
Tom E


berate is 8 and benign is 9

 

RE: What "teflons"?, posted on February 13, 2017 at 18:50:24
madisonears
Audiophile

Posts: 1201
Location: midwest
Joined: September 6, 2006
The caps that are in there now hardly fit. How will any foil cap be made to fit?
berate is 8 and benign is 9

 

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