[JamieMcC]

90uf made up of 3x30uf mbgo + the Teflon bypass they are the output coupling capacitors for a OTL tube amp.

 

[dimkasta]

Try using the thickest wire you can, and attach the signal wiring to the middle of the rails to minimize and balance inductances and resistances between the caps that might introduce weird stuff in the sound.
 
From what I remember there are also some MBG caps at 100uF which should give a cleaner sound than 3 smaller ones in parallel.

 

[dimkasta]

Further to vibration damping, I got some Dynamat today to dampen my turntable platter, and of course I had to test it on caps too.
 
Very nice results Love it and very easy to apply... I think I found an easy replacement for wood/wax

 

[lehmanhill]

 
I realise we all want the best for our efforts to be worthwhile, and hope to find the answer out there, but us what build a lot know that some of the gains are quite low level, and it's the cumulative effect we're striving for - but, and it's often the big but - sometimes there's only so far you can push a particular circuit you are working on, and greater gains will be found elsewhere in the chain.......
 
Don't get me wrong, I do personally like all this tweakery, and will be doing this beeswaxing business throughout the next build, but after that will leave it there, as I think I'll be in danger of chasing stardust.

nhall,
 
The key thing here is for each person to find what sounds good to them, in their system, and enjoy the process.  I guess that is why these inexpensive Russian caps make for a fun project.
 
That said, I have tried a range of caps based on the reviews of guys like Jon (here) and Tony Gee (humble homemade hifi).  I have been surprised that, even though my system is very different from theirs, I found their reviews to be true to my experience in most cases.  Unfortunately, that has led me to try a few more expensive caps that I would have never believed I would have paid for a few years ago.
 
Have fun.

 

[mcandmar]

2nd that.  I've used a variety of different caps from Russians, Mundorfs, Claritys, Solens, Wimas etc and my finding were pretty much the same as what those guys said in their reviews.    I did recently pick up a set of Jupiter caps at a reduced price, but as you say I would have never believed I would pay that much for caps a few years ago, or lust after headphones with four digit price tags.  Its all going down hill...

 

[JamieMcC]

 
Its a slippery slope and my cap box runneth over and that's not even all of them! Luckily I have a couple of projects coming up. Its proving to be both a lot of fun and educational plus relatively inexpensive compare to past hobbies such as scuba, fishing, archery etc and if needs be they can all go on the bay.
 

 

[dimkasta]

I have the exact same Stanley case filled with awesomeness
 
I need to get a few more though...

 

[lehmanhill]

 
 

 
With all this discussion about the Russian caps, I realized that there wasn't a review of the K71-4 polystyrene Russian cap. I have used this cap as an input DC blocking cap, a small value bypass cap, and as part of a tweeter passive crossover and it has been one of my favorite, low cost caps. It's definitely larger than most polypropylene caps of the same value, but at an ebay price of about $2 for a 1 uF cap, it is very cost effective. They are available in values from 0.01 to 10 uF that makes them useful in a wide range of projects. Other polystyrene caps, both US/Euro sources and other Russian sources are typically smaller values in the pF range.
 
Traditionally, polystyrene has been thought of as a good material for caps that are stable and linear at high frequencies. In the case of the K71-4, this is true, but they are also capable of cleanly passing the whole range of audio frequencies with overall excellent balance. For example, used as a full frequency range, input cap on an amplifier, the K71-4 (1 uF) has excellent deep bass, clear and uncolored mid-range, and very good high frequencies. Their sound stage is very good and the detail provided is very good for the price range. Their overall character is balanced, but a little on the cool side. If you have a system that is already warm, the K71-4 might be an excellent match. On the other hand, if you are looking for that mid-range warmth that you can find with a bypassed K75-10, then the K71-4 probably isn't your choice.
 
So, how do they fit into my full range of caps? In my opinion, they easily beat Obbligato Gold, Jantzen Superior Z, and Sonicap Gen 1 because the K71-4 is balanced and more neutral, at least in my system. I find the K71-4 on par with the Audyn Plus caps, just a little different trade-off in character. I was surprised to find that they have a similar character to the Mundorf Supreme caps, very neutral and slightly laid-back, however, the Supreme seems to have quieter backgrounds and more detail that make them worth a bit more. At least in my experience, it takes seriously more expensive caps such as the Rike S-Cap and Mundorf Silver Oil before the detail and sound stage are significantly improved.
 

 
In a crossover, anytime you need a relatively large value for a tweeter section, K71-4 are worth a try. I have two 10 uF and two 1 uF in parallel to form a 22 uF cap in my crossover. Once again, I compared this combination to Audyn Plus and Obbligato Gold and chose the K71's.
 
One more thought. I haven't gotten around to it yet, but K71-4 caps are a good candidate for peeling the aluminum outer to see if it opens up the sound. All polystyrene caps are film and foil caps and these don't have any oil, so going naked should be a straight forward proposition.

 

[dimkasta]

They look like the K73s so be careful stripping them. They are easy to snap the leads

 

[lehmanhill]

I'm sure they were built by the same company as the K73's.  They appear to be the same aluminum tube with rolled crimps in each end.

 

[JamieMcC]

Well there is only one way to find out so keeping a open mind I'm also going to try having a play with some inexpensive Russian Teflons to see what happens.
 
This is the progress so far with my first attempt.
 
Cutting the ends off was quiet easy with a pipe cutter pulling the ends of was a little nerve wracking as I was unsure how the would separate from the actual caps but the pins that stick out are turned out to be attached (soldered) to some short flexible leads which look like they could actually be silver, My tube amp can get quiet warm inside  space is at a premium so I decided to use a resin instead of a wax. While I just poured the resin in I want to try another method in the future as I have a small vacuum pump and think it should be possible to infuse the resin into the wood tube under vacuum to ensure there are no voids or airspaces within and give some confidence in uniformity and repeatability.
 
I will give it clean up and apply a coat of oil or varnish to the wood to make it look a bit more pretty on the outside the oil most probably not sure which type but I have noticed in the past with building and oiling wooden amp enclosures some types of oil will give off a lovely aroma when they start to warm up so will try and find something interesting sent wise to try I feel a raid on my other half's essential oil collection coming on!
 
 
 

 
 
 

 

 

 
In this last pic this cap is meant to be a copper foil picked up on ebay for not a lot http://www.ebay.co.uk/itm/181377230306?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 
but its clearly not with no sign of any copper any ware in its construction to be seen so beware.
 
 
 

 

[pelopidas]

Well? Don't keep us hanging
 
How does it sound? Do you notice a difference with the denuded teflons?
 
My good friend just got married and I have him my amp as a wedding present, since every time he came over, he loved listening to it as much as I did.
 
This is good news for me since I get to start over and refine everything, from components to layout. One of the things I hadn't tried yet were FT-1 and I too want to strip them down and put them in a wax tomb. Although, it seems dynamat might be quicker and easier. There is something about stipping it down and recasing it that makes it feel like its yours and that its more special.

 

[Doc Now]

Are this caps  http://www.thel-audioworld.de/bauteile/glimmX/glimmx.htm  unknown in the US Hifi circles?
They came from Cornell Dubilier and have a very good reputation in Germany.

 

[dimkasta]

I have not tested those, but I have tried the Cornel Dubilier silver micas on my phono and my CD transport with excellent results. Smaller values though at 1nF and 3nF. The CD ones are cheaper as well. The 47nF cost something around 35euros if I remember correctly
 
By the way, I received a batch of 20 3nF FT-1s to check on my phono, but some of them were duds. That was the first time I came something like that in russian caps. About half of them were measuring ~1,4nF and the dissipation factor was all over the place. I managed to get 2 matched pairs with almost 0 D, but I had to discard around 10 of them as absolutely not usable.
 
As a first indication, the leads were almost black and had to be sanded. I guess they were stored in very bad conditions since it is the first time I see something like this, and I have bought a lot of Russians in the past.

 

[pelopidas]

dimkasta, have you tried denuding the damaged FT-1's to see if it is just the exterior leads that are damaged? It would be interesting to know if the inside is still intact.