Eros Cap Questions From The Old Board

[Grainger49]

Since the old board is locked I wanted to mention that the use of the KK Teflon advertised as "200V, Tested at 1000V" capacitors were advised against by PJ a while back.

I have seen 0.1uF caps rated at 200V, 500V and 600V.  As PJ mentions the manufacturer understood the dielectric strength involved when they were made and rated them accordingly.  

Both poster Paully and I intend to use a pair of 0.22uF@600V caps, on each channel, where the 630V Solen 1.0uF caps are in the kit.  (output caps)  I'll have to buy a kit first, but I fully intend to do that as soon as I get another contract job.

Another thing worth mentioning here, I have read a post from CaucasianBlackplate (Paul Birkeland) that stated the original design was for a 0.47uF cap on the output; the 1.0uF Solen PP was an upgrade in quality; the increase in value yields no additional musical information.  So the sum of 0.44uF KK Teflons would be right up there with the design value of 0.47uF.  Well, almost there.

I hope this didn't ramble too much.

Edited to insert the correct values.

[Paul Joppa]

...
Both poster Paully and I intend to use a pair of 0.22uF@600V caps where the 630V Solen 2.2uF caps are in the kit. ...

No rambling problems, just some decimal places ...

The output stage of the Eros is the same 6922 tube as Seduction, so Seduction's 0.47uF should be adequate. The stock Eros output is 1.0uF Solen (not 2.2uF!).

Two 0.22uF caps in parallel would make 0.44uF which is plenty close to 0.47uF. It would be perfectly reasonable to try a single 0.22uF as long as the Eros drives a load impedance of 50K or greater; this would give you a chance to compare one vs. two in parallel.

[Grainger49]

Thanks for the verification. That is exactly what I needed.

The problem isn't decimals, it is old age.  Well, and that I didn't build the Eros so didn't have a schematic handy.  I should have gone upstairs and looked at the schematic.  (I edited my post so there isn't a misleading value there)

We will try one versus two also.

[Grainger49]

And from the ridiculous (not you Paul) to the sublime... I have been looking for Teflon caps larger than the 0.47uF@200V and 0.22uF@600V.  A seller sent me a link for 0.68uF@600V KK Teflons.  He says that the 0.68uF@600V are scarce as hens teeth.

For amusement only (I have sent it to my brother, he speaks Russian, for some translation but I think I get it.):

http://sovietsouvenirs.com/FT.htm

No connection to this guy other than having sent an email through eBay.

[Mossback]

Hi Grainger,
The largest USSR surplus FT-3 Teflon cap I know of is .47mF. I like the FT-3's. They sound great and cost very little. The down side is their huge size. I find they take at least 100 hours to sound fairly good, at 200+ hours life is good.
The outstanding VH Audio Teflon caps take much longer. I have two VH Audio Teflons in my Wright-Sound preamp but they are beyond my means now.

[Grainger49]

Yes, I have bought the 0.47uF@200V and the 0.22@600V KK Teflons.  The Eros needs the 600V rating.  Have you found a 0.47@600V?

I always break in Teflon caps for a week or two on my GainClone.  That gets you 90-95% of the way there. 

And, where have you been hiding?

[Mossback]

The FT-3 caps rate at 600v.

[Grainger49]

 Mossback,

I recently bought some 0.47uF@200V FT-3s.  They are unusually large diameter caps.

[Grainger49]

I received a few caps the other day and have them burning in two at a time.  The first pair came off and hit the stack of already burned in caps I have.

The big honking ones in the picture below are 0.47uF@200V, the mid sized ones are 0.22@600V and the little are 0.1uF@200V.  I have bought two batches (20 each) of the 0.1uF@200V and sent a few out to Bottleheads around the country.  A quartet went to a Bottlehead in Germany.

I measure them with my meter before burn in and then put the number of days they were burned in on them when they come off the amp.