[dimkasta]

I just received the K73s and hooked them up for low vol late night listening

First impression is really positive. Much better timing and clarity... I guess you do not hear the drawbacks of multi-bypassing unless you back to single cap

Other than that they sound a bit thin but this is expected for new and freshly soldered caps....

More tommorrow ... Too much ouzo for me tonight

 

[dimkasta]

The K73s are a weird animal so far...
 
A few hours of breaking in and I love their extension to the highs. Not so much to the lows.
 
I love the timing. Bass kick drums burst exactly with the cymbals for example.
 
I do not like the clarity so far. Not that it is bad, but it is quite lower than what I was hearing with the combo and the FT3 alone. But I will give it a couple of weeks.
 
Oh and I have to say that mechanically they are loose inside the chassis. Some mechanical strength should clear them significantly...
 
Oh an I couldn't resist them being so cheap
 

 
You can just cut the can a bit and then with you pliers peel it moving the pliers in circular motion off like in a tomato juice can.
 
The green ceramic is attached to the leads, so these cannot be removed.
 
Oh and the leads seem copper on the inside.

 

[pelopidas]

It is really interesting to see how different the caps behave on different systems and different positions.
 
Are you running 10uf? I did notice a difference between the 2.2 and the 4.7 in terms of how long the break in is. The 2.2 sounded really good within 2 hours and then fantastic after about 20 hours. The 4.7 took significantly longer. It sounded a bit wobbly in the beginning and after 10 hours that calmed down. The bass started growing after 20 hours or so and after 2 weeks it is just beautiful. For me in my setup the bass is deep and tight. More so than any other cap I have tried.
 
At my desk I have the Tripath 2024 where I do all my preliminary testing. My main system is a tripath 2050 from Hifimediy. When I first started modding it was with Daytons. Both systems sounded pretty identical and I thought they were the cats meow. I put the 4.7 K73-16 in the TA2050 system, to see what it sounds like and damn, its not as good. My little 2024 just blows it out of the water. So after thinking about what the problem is, and looking at the components on the 2050, I think I know why I have hit a wall. I had replaced the output inductors, same as on the 2024. But what is not yet up to spec is the other capacitors. It has some no-name (at least I cant find it) power reservoir 1200uf cap.
 
I know the tripaths are very sensitive in this area because I used the Panasonic FC for the 2024 and that really made a tremendous difference. However, the Panasonic also truncates the bass and so now its onto Silmic II. Without replacing this cap, all other mods have no effect on the 2050. No amount of bypassing, changing caps (except the k75 which makes it worse) has any effect at this point. It is as though that one stupid cap is the gatekeeper and only lets so much through. So now I have to play around with different caps on that. I will try some Silmic II first and see if it has any effect.
 
Keep us updated on any changes that your K73 might undergo. BTW I did end up leaving it bypassed with the K72. After it settles down, perhaps you can try that too and see what it does.

 

[dimkasta]

Yes I am using 10uF. I tried 4.7uF but had significantly less bass in my rig.

Putting the K73s inside wood sealed with wax changed them significantly. Clarity is significantly improved. If you have them loose in you chassis then at least tie them firmly with some tie wrap.
Bass is still a bit softish though. And still not as low.
But highs are very nice. I am wondering how much better these will get with some time in them

 

[pelopidas]

I am very curious about the nude capacitors. Is wax used just because it is convenient to use? Why do you think there is a noticeable improvement. This now has me looking at my capacitors wondering if I should pull them all apart now and sink them into some wood. Also, which wood is best? A soft wood or something like ebony that is rock hard? Is it just to remove the metal casing for magnetic reasons? Does it damp vibrations? Now I need to know.

 

[dimkasta]

Well as you said yourself, most capacitors have piezoelectric properties.
 
The rationale behind removing the metal casing is that it has a high resonant frequency which is more difficult to tame. Using wood and wax brings this frequency further down where it can be handled using mass and damping. Wax is just convenient for me since it is very easy to melt and use, and has excellent damping and sealing properties. Just note to use pure beeswax which has a higher melting point, and not some wax blended with paraffin or other additives, like in candles. Care how you use them in hot systems, like amps etc.
 
About what wood to use, whatever works for you. I would not sweat much about it in such small areas and masses.
 
That been said, it is not an exact science. You need to experiment since it has a lot to do with the rest of your construction. And you might get perfect results just attaching the caps tightly to the chassis with some thick tie-wraps.

 

[nhall]

Just opened a K73-15, which outwardly looks very similar to your one, however, there is the addition of a nylon type end cap partially covering the two coil ends before the green ceramic paste .. this model is also supposed to be the same generic type of PETP cap, but shows there can be slight differences (would have added a picture, but apparently cannot on my first post here). This one I opened was one on the outer limits of the 5% spec. so I wasn't going to use it, but it was opened to see the make up before I did a matched set for my pre.
A while back I saw some of the others demoing their wax potting, using drilled hardwood blocks and beeswax .. just thought I'd throw it in there that I did a series of Panasonic 1000mF caps recently, and as I didn't have the space, simply made a jacket by rolling paper into a nice stiff tube .. didn't even protect the innards on mine (after first experimenting on the least matched one) and to my amazement they all held their capacitance perfectly and sound great. Part of the reason I tried without first wrapping the innards, was because having done a lot of guitar pickup potting in the past I liked the idea of the wax getting in the central core as well to add as much damping as possible. I fathomed that if you're gonna damp something, might as well go the full monty!

 

[dimkasta]

For such modifications in capacitors, I would also measure and made sure the D factor is not altered. Not just capacitance.

 

[nhall]

Thanks DimKasta - yes dissipation factor - I should get over to my mates more often as he has all the test equipment.
Have you run physical tests that nailed the physical parameters which most effect (or should I say alter) it's D factor? .. would be really interesting to know?

 

[dimkasta]

No not really.
Dry caps should have little problems. Petps are held with some nylon and teflon is resilient to heat. It's possible leakage in the layers that worries me more. Although wax is thickish and should't get inside easily

 

[dimkasta]

Now with oils and electrolytics, heat might change the liquid or speed up its polymerization, especially since we mess its sealing

 

[nhall]

Gotcha .. thanks for sharing that.. I'm sure you are right - the Oscon I saw apart had a pretty solid outer coating, whereas the Panasonic was more like a PIO in that it had quite a wet oil soaked paper inter layer, and was not as stiff in its overall structure, however, as you say, the overall 'potting' will seal the whole winding, and no doubt better that the rubber gasket at the base of the Panasonic which relies entirely on tightness of fit of the rubber to the lead out wires.
With a thick layer of wax between core and outer casing I wonder how much influence the wood actually has on the overall end performance, or, whether it has been found that a thinner wax layer allowing greater coupling of core to sleeve is more desirable, otherwise, the type of wood choice is more about protection and handling?
Too much to explore - too little time to do it in!

 

[dimkasta]

To be honest I like using Wenge wood because I have it, it is beautiful and it works nicely. I have not tried anything else. Just some red Mahogany sipo which was not easy to machine and splits very easily.
I have used mdf and ply with nice results in other damping applications, but never really though of using them with caps... MDF might be a good idea... It s very close to the cardboard used by Duelunds and has excellent damping properties.
 
I will try it at some point, but I do not have a thick enough layer right now. I could make one out of glued rings, but it will be ugly

 

[nhall]

Bye the way, have you ever managed to get your hands on any of the Jupiter capacitors, or those old 50's beeswax capacitors (not the loose cardboard covered metal can ones)? .. just that some of them look to only have a cardboard shell!
 
Wenge is a nice wood .. I know it well from my guitar making, and I believe some of the Denon re-casing chaps use it a lot.
 
mdf has some good damping properties, however, probably would need a lot of treatment to seal well for longevity / handling - if used with too thin a wall it may in fact be much less robust than a wound cardboard tube made from treated paper.
 
You might even look to some of the man made materials (if you aren't going down the nature path) and then could search out offcuts of kitchen worktop installations for instance - in Lab's they often use compressed paper/resin sheets like Trespa or Richlite, or new eco kitchens often use composite bamboo in thick sheets - but then what about going to your local garden centre and selecting a reasonably straight bamboo tube of the right diameter?

 

[dimkasta]

No Jupiters for me so far.

I love wenge fingerboards by the way