Jupiter Caps in tube preamp application

I just ordered some Jupiter Copper Foil caps for my Art Audio Vinyl Ref preamp but now i am thinking maybe that is a bad idea due to temperature issues? Jupiter says they are designed to work up to 80C which is high but was wondering what others think about this. Advice is appreciated.
I would think that as long as the caps are not directly adjacent to the tubes you should be ok.
FWIW I use the Jupiter copper foils as the interstage coupling caps in my ARC VT100 power amp I do have them mounted on the backside of the PCB opposite the tubes.

Dear @jimbones  : Which caps in your preamp you will change and which caps are the original ones ( I mean manufactured by ) ? what are you looking for changing the original caps. Something wrong with these ones.?

Regards and enjoy the MUSIC NOT DISTORTIONS,
when I first got the preamp it did a LOT of things well, with the exception that it was just a bit hard/forward in the midrange. Looking to mellow it out a bit.
Dear @jimbones  : Ok, you are looking for a " tone control " and that's exactly what the boutique/high end caps does it but if in the future you want true MUSIC not colored one then give a chance to Wima MKP 10 or FKP 1 models and you will be heavy surprised by, just non-colored high quality performance levels.

In the mean time enjoy what you have.

Dear @jimbones  : Good that that is what you are looking for to achieve your targets and this is what it matters.

OK so I did the swap and it want all that dramatic. Sounds clear as a bell I wouldnt classify it as a tone control. I dont hear any shift in tonality or any emphasis is any one area except maybe a bit stronger in the low bass region. This may be due to a difference in cap value (approved by the designer). I guess there is a break in period hopefully not as long as teflon lol
If you did it right you should hear deeper into the recording, more detail but in a smoother more natural way that may not be all that obvious at first, and this realistic smooth coherent sound will only become more natural and organic as the hours add up. That's a real good cap swap when you get that.

There are only two times anyone should be talking about tone controls with caps: in crossovers where the value does directly affect response, and when the listener isn't able to appreciate that the areas described above got better, instead noticing only the lack of grain and glare, which they misattribute to being toned down. Since you went the extra mile to check with the designer then you are quite correct to dismiss the poor listener and his misinformed tone control comment. If yer gonna mod, do it right- which includes knowing what to question and what to stand up for. Which you did. Well done.
@millercarbon, thank you for the thoughtful and respectful response. I did notice it was a bit smoother, Not to be confused with loss of detail. I will need to get more listening time in but there may be more detail. I did go from a 0.01uf to 0.022uf so there may be some effect from the value change as well. I'll keep you posted as to break in improvements. Thanks.
I noticed an increase in bass as well with the Jupiter caps when I put them in my amp. I would give them a couple hundred hours to settle in although they do sound pretty good when first installed.

Thank you for sharing @andirocks/Scott. Good to hear this feedback as it validates what I am hearing.

Dear @jimbones  : "   I wouldnt classify it as a tone control. I dont hear any shift in tonality or any emphasis is any one area except maybe a bit stronger in the low bass region. "

Again, all high-end/boutique caps are way colored and we like those " nice " colorations but at the end are only added distortions.

Your statement confirmit. Bass range is where belongs the home room/system foundation and through the bass notes and its harmonics puts the whole tone of those speakers, so any tiny change in the bass range response will affects all the other frequency ranges.

The only way for a cap been nota " tone control " is that that cap be signatureles and Jupiter certainly is not a signatureless cap as any other boutique caps.

The adjective smooth is an audiophile and tube lovers adjective but near field live MUSIC is everything we want but smooth.

Unfortunatelly and form many years We are accustomed to that kind of smooth sound and we like it but even that is wrong live MUSIC characteristic because just does not exist down there.

In the Humble home made.. caps comparisons Tony stated on Jupiter:

"  The Jupiter Copper-Foil Paper & Wax used as a bypass capacitor in loudspeaker crossovers creates a nice balance between warmth and detai.."

you can note that " warmth " word that is an audiophile word that does not exist in live MUSIC.

It's imposible for caps using paper, wax, oilñ and the like to starigth/signatureless because the audio signal " touch " that kind of materials that are far away to be technology not even exist white papers that can prove are the best dielectric/caps materials, however Jupiter said:

"   Our wax & paper capacitors are a blend of old and new technology ""

that old pseudo-technology came from 70 years ago when was used for radio caps. Go figure and Jupiter is not the only one that choosed that " technology ".

It's not science because a cap manufacture is not a rocket science and what I stated is only common sense.

Btw, Tony posted in his caps comparison papers:

""  The Jupiter Copper-Foil Paper & Wax seems to have everything you are looking for in a capacitor: a coherent and organic presentation, detail and smoothness come hand-in-hand, a well controlled and focussed image, rich and transparant overtones.."""

" organic, smoothness, rich.."" all are audiophile adjectives we are accustom to but that's is not live MUSIC.

Seems to me that we love audio hardware over MUSIC and could be because is what we like.

Jim, it's not a critic against you NO, is only a different way to see " things ".
That's why @millercarbon can't understand my overall take.

Btw, it's not at random that you and @andirocks  coincide in that " low bass " characteristic with the Jupiter because that's part of that colored sound because he detected the same but with his amp and you with a preamp and both in different application inside those units. That's is a coloration7added kind of distortion and that's what millercarbon can't understand or he looks in a different way. 

""  with the exception that it was just a bit hard/forward in the midrange. Looking to mellow it out a bit. .. """

well maybe you already achieved what you are looking for.
In the other side obviously that the unit designer voicing was different of what you " like " or do not like.

Anyway, enjoy it.


Dear @jimbones  : For years I was using caps as Duelund, Mundorf, Jantzen, V-caps, Sonicraft and the like suddenly I made a " crazy " change and a few months ago I " discovery " that WIMA caps are the true path to go. It's a non-audiophile cap but it's the any kind industry ( just name it.. ) proved and real Standard and for very good reasons No snake oil with Wima.

One month ago , between other before changes,  I pull the triger for an extremely critical caps change.
Things are that for years the high-pass filter in my bi-amp system I did/do it through the Levinson monoblocks input cap.

This cap is not a by-pass cap but the Levinson input coupling cap where all the frequency ranges goes throuth it, as I said really critical system cap.

Well I was using there a V-cap Teflon Cu ( 100.00 each one. ) and I changed for the FKP-1 Wima cap and this really humble cap outperformed the V-cap with an unexpected easy.

When you can take it a time you can buy ( 2.00 each cap. ) the original 0.01uf  Wima FKP 1 and you can test it and see what happens down there, of course that you can buy too ( are so inexpensive. ) the 0.022uf ones.

Don't be " intimidated " by the ridiculous non-audiophile Wima caps, just try it and decide after that. You can lost nothing and can achieve some rewards and at the end is something to learn and " fun " to do it.
Btw, no colorations/nice distortions through Wima, only the signal with no added " colorations " you can detect:


In my speakers crossover I use the MKP-10 Wima model.

Regards and enjoy the MUSIC NOT DISTORTIONS,

Dear @jimbones : I used too REL caps years ago and I can say for sure that in my first hand experiences today no other cap can beats Wima.

As I said you can't lost anything with.

@rauliruegas Will do. BTW I have been thinking about your previous posts regarding accuracy. what is "accuracy" anyway? How can you be sure that once component is more accurate over another. I know I am not qualified to make that judgement. I DO know what I like. So if something has an irritating edge and sounds hard that is more accurate because thats what music sounds like? I am not sure i agree. I stopped chasing accurate years ago. If something sounds like crap, I don't care how accurate it is, I don't like it. I think that most higher end audio equipment is good and is a matter of taste. Compare two $10K DAC's, both are most likely very good, but you will have a preference. And that is OK because you should. I think audio equipment has come a long way and there is a lot of good stuff out there to enjoy. No Stress.
what is "accuracy" anyway? How can you be sure that once component is more accurate over another.
If you make your own recordings, you’ll know what is faithful to the original event. This was actually a rather common practice in the old days of hi-fi.

It strikes me odd that so few today experiment by making their own recordings. It's never been easier to do, or more affordable to achieve excellent results.
So true, with software today it is easy. So I don't make my own recordings so therefore I am a little behind in that area. I am an older audio guy from way back and I am tired of chasing. I got away from the hobby for 15 years and when I got back I promised I would go back in with my eyes open and just try to build a system that satisfied me and not worry about the latest equipment in the magazines. I am at peace with my system Lol!
Dear @jimbones : Accuracy can means several things depending on what we are judging and accuracy is only one part of an overall audio item design.

Accuracy with out a good item design is useless. Accuracy must comes along good design with good passive and active parts.

Example: accuracy is always welcomed in the inverse RIAA eq. phono stages but it does not matters if the design is a bad design.

Everything the same accuracy makes the difference for the better. Accuracy is always a measurable characteristic.

Regards and enjoy the MUSIC NOT DISTORTIONS,

Whoever stated warmth is not in part of live music ,never heard  a  live event 
jazz , standup bass , bass guitar ,acoustic guitar woodwind instruments ,drums vocals ,piano, and a combination of all above , Jupiter Copper foil waxed paper are very natural and night and day better then the vast  majority of stock average  capacitors low quality like Solen , or China specials  in Loudspeakers.