My Capacitor comparisons: Mundorfs, VCap, Sonicap Platinum, Auricap, etc

Jon L · « **Reply #340 on:** 5 Jun 2009, 11:00 pm »

Russian K72 Teflon Capacitor "Nude"

I always had a soft spot for the Russian K72 teflon capacitor, which was the original Russian teflon wonder that DIY'ers picked up on, and the rest is history. It had tons of detail and dynamics, but it had a tendency for a bit of hardness and etch, which some suspected was partly due to its thick steel case and metal posts.

I was able to test the "nude" K72 that has been de-cased and de-posted (courtesy of Josh K), and I must say this version loses most of the hardness and etch of the stock unit. After a long break-in, the sound is almost creamy-smooth in the low-treble and upper-midrange while the detail and dynamics remain.

What I have always liked about the Russian teflons, including K72 and FT3, was that while they don't quite have the air and refinement of the VCaps or Auricap Teflon, they actually had a bolder and more robust presentation that projected more forward with arguably a more involving mien. Now with the nude mod adding smoothness, K72 must certainly be *the* giant-killer, right?

Well, almost. The nude mod ended up sounding a little too creamy and smooth up top. There was terrific detailing right up to the midrange, but the triangles, cymbals, and violin's upper harmonics did not ring clear in sparkling fashion. Wait! I have heard a very similar sound previously... It was the Audiocap Theta, and adding a small FT-1 teflon bypass capacitor was the sweet answer then, so I tried the same with the nude K72.

2200 pF FT-1 Teflon Capacitor

Holy Batman, now things were really cooking. Since FT-1 is basically the same internally as K72, adding the bypass did not result in any appreciable incoherence or discontinuity, just adding that last breath of air, upper harmonics, and sparkle. The resulting sound was at once robust, dense, detailed, and airy, while being as smooth as baby's behind. I really liked the results, and if you have some K72's, I highly encourage you to crack open the case and add the FT-1 teflon bypass.

kkf · « **Reply #341 on:** 8 Jun 2009, 01:55 am »

thanks for the info and the work

KT · « **Reply #342 on:** 8 Jun 2009, 05:38 pm »

Wow, great writeup on the Russian Teflon, Jon.

Do you recommend any sort of protection for the nude cap, from oxidation for example? Maybe dipping in wax or coating with varnish?

I saw a website once where the guy nuded some of his caps and put them into custom-turned wood cylinders. I believe he sealed them with wax afterward (can't remember). The project seemed very craftsman-like, and made sense to protect the caps. How the mod changed the sound of the caps is, of course, a point of discussion, but it seems to be a viable way to protect the nude cap if needed.

Best,
KT

Jon L · « **Reply #343 on:** 8 Jun 2009, 10:11 pm »

Quote from: KT on 8 Jun 2009, 05:38 pm

Do you recommend any sort of protection for the nude cap, from oxidation for example? Maybe dipping in wax or coating with varnish?

Remembe what these look like inside.

Coating with varnish is a nice idea, but wax is probably going to be too soft.

Hot glue was tried, which just doesn't stick well after a while.

I couldn't find the right size heatshrink for these, and even if I could, one would have to seal the ends with something.

A low-tech approach is to just mummy-wrap with electrical tape tightly, mainly for mechanical protection, not being air-tight. Remember it's aluminum foil inside, not copper.

JoshK · « **Reply #344 on:** 9 Jun 2009, 03:11 am »

I can't remember if I detailed how I took apart the teflon cap. It is really straight forward but takes a bit of effort (patience daniel-san). I can do another and hopefully take pictures to detail it if you guys are interested.

I read that some wrapped the caps in boxing tape after taken apart and then seal the ends with hot glue. That is what I did. The cap will actually unravel like a toilet paper roll if you don't wrap them in something. Be careful also to not let any of the foil fall out. It looks as though there are some small pieces of foil wrapped in the end, probably to trim out the value to be within spec.

I used hot glue to seal the end and it actually makes the boxing tape melt. The boxing tape is wider than the cap is long, which means you will have extra length on both ends that you can fill with something to seal the ends. When you put hot glue in this the tape melts into the glue. I would have thought that would hold. Maybe some else has a better idea?

kyrill · « **Reply #345 on:** 9 Jun 2009, 10:42 am »

I would advise to take low dielectric constant materials to protect the nude caps and if possible with damping resonance properties

JoshK · « **Reply #346 on:** 10 Jun 2009, 09:00 pm »

Quote from: kyrill on 9 Jun 2009, 10:42 am

I would advise to take low dielectric constant materials to protect the nude caps and if possible with damping resonance properties

Which do you suggest?

Occam · « **Reply #347 on:** 10 Jun 2009, 10:47 pm »

Howzabout teflon tape, possibly the thicker yellow gas line version. I hear tell its dielectric properties are quite good. FWIW

JoshK · « **Reply #348 on:** 10 Jun 2009, 10:57 pm »

What do you use to keep that from coming unraveled?

dweekie · « **Reply #349 on:** 11 Jun 2009, 03:33 pm »

I see nothing wrong with packaging tape. 3M Scotch Packaging tape is made from polypropylene. Datasheet here.

http://multimedia.mmm.com/mws/mediawebserver.dyn?6666660Zjcf6lVs6EVs666&y1COrrrrQ-

rajacat · « **Reply #350 on:** 11 Jun 2009, 03:44 pm »

How about this self bonding rigging tape? I've used this in marine applications and it's very easy to use and should have good vibration absorbing qualities.
http://www.jamestowndistributors.com/userportal/show_product.do?pid=14638&familyName=Rubbaweld%26reg%3B+Rigging+and+Mast+Boot+Tape

-Roy

KT · « **Reply #351 on:** 13 Jun 2009, 05:04 am »

I found the article about the wood-encased capacitor. Here is the link:

http://www.dhtrob.com/impressies/elna_inhout_en.shtml

http://www.dhtrob.com/keesolaf/elco_en.shtml

http://www.dhtrob.com/projecten/elna1_en.shtml

What do you think?

Best,
KT

jtwrace · « **Reply #352 on:** 19 Jun 2009, 01:22 am »

Quote from: jrebman on 31 May 2009, 10:58 pm

jtwrace,

That's the same combination I plan to try in my Havana DAC (different values though), so I'd be interested to hear what your take on the sonics is like.

-- Jim

Jim,

I did the upgrade and am realy impressed. I cryo'd the whole unit while I was doing this. Anyway, everything that I've read that it would do, it's done! Get's better every day...

markC · « **Reply #353 on:** 19 Jun 2009, 02:30 am »

Quote from: JoshK on 10 Jun 2009, 10:57 pm

What do you use to keep that from coming unraveled?

The thicker version that Paul speaks of is unlikely to unravel if applied with some tension. I used the yellow variety on the ends of jantzens and it is still holding after several months. I had the unit in question open a month ago. I will be performing more "surgery" in the next few days, so if I see any issues, I will report back. But, I doubt it. I use this stuff at work all the time.

Jon L · « **Reply #354 on:** 23 Jun 2009, 03:35 am »

ERO KP1832 Polypropylene Film and Foil Capacitor

This "KP" series capacitor is a genuine film and foil capacitor, unlike the metallized polypropylene "MKP" capacitors. It's difficult to find a consistent source for these NOS capacitors, but they often turn up on eBay in small uF values and have long been considered excellent-sounding in DIY circles.

Due to their small values, they are mostly used as bypass capacitors, and this is how I have tested them as well. So far, my favorite bypass capacitor has been the Russian FT-1 teflons, which simply shines when bypassing certain capacitors, e.g. Russian "nude" K72 teflons or Audiocap Theta. However, there are other capacitors that sound too different from FT-1 as to end up sounding incoherent when thus bypassed.

This is where a nice polypropylene film and foil capacitor like KP1832 can come in handy. It lacks that slightly artificial glint metallized poly caps can impart while still extending the upper frequency and air. Its sound is quite natural and not showy at all, which may not give an ear-grabbing, exciting presentation, but it certainly does its job.

A good bypass cap applied correctly, with some luck thrown in, does not make the sound brighter like some may think, but it actually makes the lower-treble to upper-midrange area sound even smoother. It's almost as if some of the peakiness in that range moves over to the very high treble, which translates into more ambience and sense of space. I have heard similar effects with speakers when adding in a good supertweeter, not turned up too high of course.

An example of a good capacitor that benefits from a bypass capacitor like this is the Jupiter Beewax capacitor. This is a capacitor I have always liked due to its natural tone and plenty of lively treble presentation. When compared to good teflon, it does seem a bit less ruler-flat through the upper ranges with some of the very top-end ambience muted. Bypassing the Jupiter capacitor with ERO KP1832 resulted in a more linear and smooth sound with better ambience and air, making a good capacitor even better. KP1832 is so promising as bypass, I hope to try them as coupling capacitors, but larger values do not seem easy to come by unfortunately.

dweekie · « **Reply #355 on:** 23 Jun 2009, 05:14 am »

Just to add a short list of some other polypropylene film/foil caps.....

One of the most readily available low-cost film/foil capacitors is the Dayton series (http://www.parts-express.com/dayton-film-capacitors.cfm). I've been meaning to try these out some time, but I haven't had a reason to use them. I've read some good things about them. Be careful since only the ones I linked are film/foil, whereas the other Dayton caps are metalized.

The orange drop 716P is probably a better known film/foil cap with a love/hate reputation. The Panasonic ecqp series is another one, but that went out of production at the end of last year.

AudioCap · « **Reply #356 on:** 23 Jun 2009, 05:21 pm »

Quote from: KT on 22 May 2009, 08:08 pm

Quote from: AudioCap on 22 May 2009, 08:43 am
Ampohm announced yesterday 22nd May that they are finally launching a range of paper-in-oil, copper-foil capacitors in 630V (0.001uF to 1.0uF) and 300V (2.2uF to 10.0uF).

Thank you for the information. It seemed like they would eventually introduce a copper version if they already had tin and aluminum. I'm curious if they'll be a big step up or just slightly different.

The new beeswax caps look promising, too. So many choices!

Best,
KT

Well the Ampohm Paper-in-oil Copper Foil (PF-XCU Series) caps are finally through production. Ampohm are also producing silver lead-out versions (PF-XCU-S Series):

AudioCap · « **Reply #357 on:** 24 Jun 2009, 03:41 pm »

Quote from: dweekie on 23 Jun 2009, 05:14 am

Just to add a short list of some other polypropylene film/foil caps.....

One of the most readily available low-cost film/foil capacitors is the Dayton series (http://www.parts-express.com/dayton-film-capacitors.cfm). I've been meaning to try these out some time, but I haven't had a reason to use them. I've read some good things about them. Be careful since only the ones I linked are film/foil, whereas the other Dayton caps are metalized.

The orange drop 716P is probably a better known film/foil cap with a love/hate reputation. The Panasonic ecqp series is another one, but that went out of production at the end of last year.

The Evox Rifa PFR series is "true" polypropylene fil-foil. Downside is that they only cover the 0.1nF to 22nF range. Excellent dU/dt, though. Datasheet: http://www.audiocap.net/pfr.pdf

NOS Valves · « **Reply #358 on:** 29 Jun 2009, 12:42 pm »

Quote from: avahifi on 4 Jun 2008, 08:40 pm

Just kind of curious. I see tolerances of anywhere from 2 percent to 20 percent in the caps mentioned. Changing the value of a capacitor will pretty obviously change the circuit operation aside from the composition of the part in question.

Nowhere to I see any mention of exact matching of values between samples to assure that the test was not just listening to value changes, not something more subtile.

Capacitors are the values they are, not the values printed on them.

Regards,

Frank Van Alstine

As a read this thread I was wondering how many pages would pass before someone mentioned the obvious. If the pictures of all the various caps are of the caps under test I see value differences from .047uf to 2.7uf... If these are the values used this entire reveiw is totally flawed. To properly do a reasonable comparison the value of the caps would have to at least be within 10%. In reality 1% would be better.
I commend Jon the reveiwer for his efforts and much of his basic opinions on the differences in cap signatures ring true with my own experience. But any of the caps used that were not of the "proper and equal value" for the application were not given a fighting chance.

Jon L · « **Reply #359 on:** 29 Jun 2009, 08:18 pm »

Quote from: NOS Valves on 29 Jun 2009, 12:42 pm

Quote from: avahifi on 4 Jun 2008, 08:40 pm
Just kind of curious. I see tolerances of anywhere from 2 percent to 20 percent in the caps mentioned. Changing the value of a capacitor will pretty obviously change the circuit operation aside from the composition of the part in question.

Nowhere to I see any mention of exact matching of values between samples to assure that the test was not just listening to value changes, not something more subtile.

Capacitors are the values they are, not the values printed on them.

Regards,

Frank Van Alstine

If the pictures of all the various caps are of the caps under test I see value differences from .047uf to 2.7uf...

Umm, I hope you don't think all those caps are being used in the same place.

In my testing setup with different gear, there are mainly 3 different places that require different capacitor values.