Capacitors for HP filters in tube amps recommendations?

pragmasi

You need to be cautious when recommending CGO/NPO ceramics for audio (particularly coupling not bypassing) applications. I know from experience that some NPO/CGO caps (particularly those from TDK ceramics) have a voltage coefficient of capacitance that is quite significant (sometimes as high as 0.5 x C) at DC voltages near rated max. This is more evident in the larger values (and .01 uF is large for an NPO).  Remember, the CGO/NPO spec relates to temperature coefficient only, and while meeting the low TC, are still quite nonlinear when stressed at various voltages. Folks have slammed the use of tantalum caps for years because of this characteristic, and some NPOs are just as bad or worse. Also, you may be hard pressed to find a ceramic cap manufacturer of NPOs providing dielectric absorption specs. Due to the large variety of ceramic compounds, it is risky to extrapolate the product of one manufacturer with an NPO compound of another.

Also, there is data that shows polypropylene has pretty much the same dielectric absorption as polystyrene. With the same metallisation, ESRs and dissipation factors are identical. Polystyrene has a major weakness in that these caps can be easily damaged while soldering, due to the low temperature ratings of polystyrene. I am not a fan of the cheap Xicon polystyrene caps, but those made by RelCap are quite good.   

You need to be cautious when recommending CGO/NPO ceramics for audio (particularly coupling not bypassing) applications.

I have question for you.

Can you use a PIO russian .01 or a pair of .015
they come in 100-1000 v.  There were a few different model numbers., I I think Y77????, not painted, glass tube..
It's been 3-4 years since I ordered 50 or so @ 600v. I matched 16 as close as I could.  less than .5 % var. I used .01 as bypass in addition too
1.0 uf coupling. They were about .25" x 1" 1.5 inch tails. I took out EROs at 400v and 10%, they were all over the map. The PIO russian surplus worked wonderfully.
Took a bit of time to break in but really softened (I think that's the right word) or took the edge off the blistering HF issue, that just kills my ears.
I'm one of those people that UHF literally makes me clench my fist and walk in circles. Cotton in the ears, or a hoodie a LOT of the time in public.

So will these caps work as an inline XO (of sorts) on line level interconnects if that is what someone wants to do?? Your thoughts

I'd like to take care of this problem in a cable format if possible. On the line in  where the values are much smaller and WAY less expensive..

Your thoughts

Respectfully

Dear @bdp24  : I know that now maybe is to late but I will post anyway because I just made a huge caps discovery.

"  If they’re good enough for Nelson..."""

My discovery was exactly WIMA caps that not only for N.Pass but for electronics in all the world WIMA is the true standard in the industry and for very good reasons I never experienced before till I tested and learned why is the industry standard.

I was using at the input of my Levinson monoblocks the V-caps teflon Cu for the same application that you are doing.
Well I just changed that truly expensive V-cap ( top of the line. ) for the humble Wima FKP 1 and Wima outperformed very easy.

Before that electronic cap change I changed all the boutique expensive and heavy colored caps ( Duelund, Mundorf, V-caps, Jantzen, Sonicraft, that I own it. ) in my 3-way crossover speakers. I use here the Wima MKP 10 model and happened the same: Wima outperformed all those " high-end "  caps.

Nothing compares against Wima, no matter what.

I came to this specific forum looking for an advice for a harmless/signatureless caps for my speakers and posted a thread about.

I posted the thread with out any agenda but looking for help and through that thread and with out any Wima recomendatiopn I pull the triger for it.
You can read that thread and know how and why I decided for Wima.

Btw, the FKP 1 and according the Wima site is the top cap for our applications and you can find out therough Mouser that is where I bougth all my Wima caps and I don't care to much of the Wima tolerance because it measured really near the capacitance values even if the tolerance is 10% or 20%.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.                   

I pulled WIMA MKG-4 .47@ 250v in a VTL 300 Deluxe, replaced them with a really good VCap. LOL, two months later thinking it was a breakin thing, pulled them and put the USED WIMA caps back in.. Sounded wonderful again. Crazy I'm with you they are a great cap, my first Watt B5 is packed with WIMA, My new Mcintosh PACKED with WIMA. High quality, LOW prices in comparison... 5.00 USD, Vcaps 100.00 USD at the time..

Regards

Dear @oldhvymec : Wima comews not only in your electronics mentioned or in my Levinson monobloks but comes too in very expensive/cost no object high end electronics:

https://dartzeel.com/en/

https://s3-eu-central-1.amazonaws.com/dartzeel/wp-content/uploads/2017/12/30104100/nhb-108-model-2-upper-front-735x470.png

http://www.theaudiobeat.com/visits/ch_precision_upgrade_addition.htm

or in this 250K+ amplifier:

https://www.dandagostino.com/products/relentless-monoblock.php

http://cdn.dandagostino.com/images/products/relentless_monoblock_3.jpg


Passive high-end/boutique parts as caps are only the snake oil we " high end " audiophiles are looking for. All of them are full of " nice " colorations when Wima humble ones are true signatureless and harmless caps to truly honor MUSIC.

Differences between high-end audiophiles and real MUSIC's lovers are like the differences between Duelund and Wima caps where obviously Wima is for the music's lovers.

Over 40+ year in audio I just learned what I said in that last statement and I did it through first hand experiences.


R.