Replacement of tha WonderCaps in a Threshold FET/10

[Nounours18200]

I am working on the future uprade of my Threshold FET/10e HL preamp.

Inside there are some (beautiful) white capacitors, marked : "WonderCap, 0.1µF/470V, Ultima with Danon"
(i will post some pictures in the coming days).

What would be the best replacement capacitors for this ones ? (I think about Hovland ).

Thanks

[analog_sa]

MIT RTX but make sure you check and mark them for polarity as the lettering is quite random.

[Zen Mod]

Originally posted by Nounours18200
I am working on the future uprade of my Threshold FET/10e HL preamp.

Inside there are some (beautiful) white capacitors, marked : "WonderCap, 0.1µF/470V, Ultima with Danon"
(i will post some pictures in the coming days).

What would be the best replacement capacitors for this ones ? (I think about Hovland ).

Thanks

why you think that you'll gain anything,replacing them ?

[Bobken]

Hi,

I think you probably mean "Wondercaps - Ultima with Danor" (rather than Danon) which were not bad caps in their day, although TRT (their makers) have gone through some updates/improvements to their caps since that earlier series.

As analog_sa said, MIT 'RTX' series are generally preferable and more 'transparent-sounding' caps, being multi-section (giving lower inductance) polystyrene and tin-foil construction, and I prefer these over Hovlands (polypropylene) in all cases where I have compared them. (A lot of instances!)

Also as mentioned, these RTX caps are slightly 'directional' and the only way to ascertain their true 'direction' is to measure them.
The only film caps which sonically outperform RTXs which I have found are some Teflon caps, but for extremely low pF values, some non-magnetic Silver Micas are not bad either.

Regards,

[Nounours18200]

why you think that you'll gain anything,replacing them ?

because they are more than 15 years old ...

Thank you for your recommandation regarding MIT RTX caps: I do not know them at all, but if you say that they outperform the Hovland or Mundorf supreme, they should be very good !

Tks friends

[analog_sa]

I certainly prefer them to Hovlands. No idea how they compare to Mundorf Supreme. In any case any of these will be a big step up from the Wondercaps.

[Bobken]

Hi Nounours & an_sa,

To set matters straight, I haven't done a true 'side-by-side' comparison between RTXs and Mundorfs in the same circuit, which is the only way to be absolutely sure which type is preferable sonically.

I have (more recently) tried some Mundorf "Supreme Silver/Oil" caps, and they are undoubtedly very good sonically, and may be easier to obtain in Europe for Nounours.

All I would say for certain is that having tried these Mundorfs, I didn't consider it would be a sufficient improvement (if any) to replace the quite-costly RTX caps anywhere in my system where RTXs are currently being used. Some Teflons are decidedly superior, though, and I now consider that V-Caps are the best I have (yet!) come across.

If you purchase RTX caps from M. Percy in the USA, he marks them up for 'directionality', but if you obtain them from elsewhere I posted a methodology which I use to determine this orientation
in post #69 in the following thread, from some years ago. Jonathan Carr added his own method in post #72 in that same thread, which looks to be simpler to set-up, and he says it is OK for lower value film caps. I guess it will depend a lot on what test-equipment you may have access to when conducting these tests, but it is very worthwhile getting this orientation correct in my experience.

http://www.diyaudio.com/forums/show...7593&highlight=

Regards,

[Bobken]

http://www.diyaudio.com/forums/showthread.php
s=&threadid=7593&highlight=

Sorry, it seems that this first reference didn't copy correctly. I hope that this time it is OK.

Regards,

EDIT. No it is not, so I will try again!

I don't know why this won't copy properly, but the thread was entitled "Black Gate 'Super E' caps", which should be found if you are interested by doing a 'search'.

Sorry about this, maybe it is my PC playing up. The same reference worked OK when I posted in the "Tripath Input Coupling Caps" thread a while ago, and this other thread might also be of some interest to you.

[Nounours18200]

Thank you very much Bobken for your feedback and comparison between the Mundorf Supreme and the MIT RTX : this is a very important information for me !

I went through the Michael Percy catalog, and I am surprised to see that the Multicap RTX capacitors are much cheaper than their Mundorf or Hovland equivalent : 1/3rd of the price... it is surprising particularly if the RTX clearly outperforms the Mundorf... (unless I made a mistake in the identification ??).

At this price, there is no reason to choose something else than Multicap RTX ?!

[Bobken]

Hi Nounours,

Maybe its a language problem, but what I said was that in my experience the Mundorfs I tried were not so much better than RTXs that I would replace them in any part of my system.

From memory, I don't think that there would have been a great deal of difference, but I didn't try them in a direct comparison, so I cannot honestly say for certain that one was significantly better than the other. With any similar caps like these there will be some differences, but what you gain with one in one aspect, the other will probably enjoy some other benefits.

If there is such a price difference, I would go for the MIT RTXs, but please be aware that other types of MIT caps do not sound as good as their RTX series.

I hope that this helps.

Regards,