Caps for crossover upgrade for Opera Grand Callas Loudspeakers

Hi, first of all excuse me for my English.
I’d like to upgrade crossover of my beloved Opera Grand Callas Loudspeakers
I’ve got a Merging Hapi as dac, Soulution 721 preamplifier and Krell Fpb 400cx amplifier, I use pure Ag Lasound cables (
Here you could find more information about my loudspeakers.
They use Scanspeak 9700 tweeter from 2khz and above, Seas 6" custom midrange from 200hz to 2Khz and two Scanspeak 8" aluminium woofers.
Woofer could be this, but I’m not sure
While midrange is very similar to this
Here is the schema of the crossover, maybe it could be quite different, I haven’t yet dismount the woofer in order to take photos, but this schema is taken from the my loudspeakers’ little sisters, the Opera Callas Diva, that are a little smaller and with only one woofer instead of two.
And here is a photo taken from Opera Callas Diva crossover.
As you can see, and in this respect I know that it’s the same as my loudspeakers, capacitors used are Mundorf Evo Aluminium.
I’d like to change the 6,8 uF capacitor used for the front tweeter and the 10 uF used as bypass capacitors for midrange in order to obtain e more relaxing and refined sound. I’d like to have more air, more natural and organic sound without loss in high frequencies extension.
I like my loudspeakers very much, but sometimes I found the sound, especially with not perfectly recorded and mixed records, a little bit on the hard side in the uppermid frequencies, especially on female voices.
I think it could depends on Mundorf Evo caps that are known to be a little "nervous", so I think to go for a Jupite Copper Foil Paper and Wax caps for the 6,8uF (eventually with a Duelund Silver 0,01uF bypass) and maybe a Jantzen Alumen ZCap for 10uF midrange cap, I know it could be better to use another Jupiter Copper for midrange, but I don’t know if there is enough space for it.
Have you any suggestions?
For midrange caps what do you think of Jupiter VT? What are the differences between Jupiter VT and Copper Foil in terms of sound? And between Jupiter Vt and Jantzen Alumen Zcap?
If he doesn't see this post try reaching out to member @grannyring, he is a modding genius.
Live with the fact it's the RECORDING.
Nice speaker. I have the Seconda. Been putting off upgrading because their not perfect, but realize they sound as good as whatever recording is played thru them.
If the upgrade works, great.
Those caps are top notch for their type. Magico uses them or very similar, and .... I don't like them! :)

I far prefer Clarity CMR + 0.1uF Copper foil bypass caps. as giving a much more natural and relaxed presentation. If money is no object, size might be though, so be sure in any upgrades you check the physical dimensions, especially with the Jupiter and Duelund copper foil caps.
It would be interesting to see the impedance curve, but the 100uF shunt cap on the woofer is interesting. They usually need 0.5 Ohms to 2 Ohms to prevent an impedance issue in the next driver up.

Don't replace it willy-nilly. Measure the ESR and add a resistor if needed.

Actually, given the costs involved here, before you begin, you should probably invest in a Dayton DATS V2.

Measure the impedance of the entire speaker, and it will let you measure the ESR and DCR of any components you pull out.

Then you can use it along with something like XSim to simulate the electrical characteristics fully.

You'll also be able to use it to help you diagnose problems when you re-assemble the crossover.

Thanl you Erik, but I only want to change 2 caps: 6,8uF on front tweeter and 10uF on midrange, nothing else.
Obviously only if it's possible to remove the Mundorf Evo and put in the same location of crossover the new caps.
So you have good experience with Clarity Cap CMR bypassed by a copper caps. Which one?
Duelund tinned copper bypass, Audyn Copper Max?
In what do you prefer CMR Clarity Cap over Duelund and Jupiter?
The impedance of my loudspeakers had to be very similar to the little sister Opera Callas Diva.
Here is their impedance and also other measurements.

So you have good experience with Clarity Cap CMR bypassed by a copper caps. Which one?

I used the Audyn TruCopper models.

In what do you prefer CMR Clarity Cap over Duelund and Jupiter?

Cost and size! But if I could afford Jupiter copper foils I would.  Unfortunately my current custom speakers require about 14uF in the tweeter, about $800 / speaker and that's just not money I have.

Mundorf Supreme <<<<< Clarity CMR (with bypass) < Jupiter

and never heard the Duelunds. I find the Clarity has a very neutral, and very open presentation. Jupiter adds sweetness. Mundorf to my ears adds a Disney-like sheen, or scintillation quality to everything and while it’s pretty, it’s unnatural and often too cool sounding for me.

Just thought I’d chime in here, as I recently installed new Duelund .01uf Pure Silver Foil bypass caps over both series and shunt caps in 2nd order crossover of well broken in ClarityCap CMR in my Merlin VSM-MXs. This is a synergistic combination of the neutrality and detail of CMR, with added warmth and bloom from the small Duelund bypass. I wouldn’t go above .01uf with this. It’s an improvement all across FR. The only downside is a slight reduction in soundstage depth. Duelund’s embellishment of the presence region is a more forward presentation. Maybe this will settle back with break-in. There is a slight loss of resolution, but no smearing or tubbiness as often found with oil caps.

ClarityCap OEM Sales

Hey @dgarretson

What uF were the Clarity you bypassed?
My experience has been that below 4-5uF I can't hear any difference in bypassing them.

I also used 0.047 Duelund pure silver caps on the 10 uF caps I have. No difference for me.

I needed at least 0.1uF to make a difference, and only on the bigger caps.

I forgot if you saw the speaker I put the CMRs in. :)



@erik_squires The series cap to the Esotar tweeter is 5.9uf. The shunt cap to the Scanspeak 8545 mid/woofer is 17uf. IIRC, crossover is around 2000Hz. The greatest change with the .01uf Duelund bypass is heard in mids to LF. The change is rather dramatic, though still a matter of taste.
Ahhhh, that makes more sense, @dgarretson

Based on my experience, I'd really love to try using smaller CMR caps to build up larger values. I think there's something about the uF being larger than 4 ~ 5 uF that matters. I don't have any money for this and barely any energy either though. :)


@erik_squires I don’t understand what you mean about uF quantity and bypass caps.
I think that all is proportional, ie a 0,01 bypass caps on 6,8uF has more effect than the same 0,01 bypass caps on 15uF.
Am I wrong?
You have said that "My experience has been that below 4-5uF I can’t hear any difference in bypassing them."
While my logic would be that the more is value of original cap and the less is the effect of a 0,01uF bypass caps.
Hi  @grunter

If a 10uF cap was exactly like 2 x 5uF caps and those were exactly 2 x 2.5uF caps you'd be correct.

However, in listening to Clarity CMR caps I have not found this to be true, but this could be due to the the specific crossover I was working on.

Audyn True copper caps are relatively inexpensive, so I strongly suggest listeners who are curious try it out for themselves, and come back and tell me I'm wrong. :D


I'd really love to try using smaller CMR caps to build up larger values

Thus decreasing L disproportionately to C increase. L and ESR calculations get messy with non-identical capacitors. Doubly so when mixing dielectrics and manufacturers .

Bottom line, one may like the change, but it's pretty much one off, in situ.

Which renders all similar capacitor and component type recommendations suspect for general guidelines!!!
In contrast to a conventional metalized polypropylene capacitor, the contribution to performance associated with the copper litz lattice embedded in the zinc end spray of CMR, increases with diameter. 
Or not.

Model up all the LC & ESR and thing can get ugly fast.

This is not to say that adding a bypass won't alter the sound. It's just that all might not agree that it is an improvement.
A very ineresting cap (sadly quite expensive) is the Lefson c-mod spk.

I've asked price and measures and they are quite small

C-MOD SPK G2 6,8uF/200V - Dimensions = 60x33x32mm - Price : 330€ / each
C-MOD SPK G2 10uF/200V - Dimensions = 60x48x32mm - Price : 375€ / each

" For your information, all the C-MOD models are actually available and manufactured with the GENERATION 2 technology (major sonic improvement from the first generation) and, for the moment only, sold at the same price than first. LEFSON website and online store will be updated soon."

Tell me the vendor.
I think resistors are overlooked sometimes. Changing from a ceramic or Mills to a Path Audio resistor in the tweeter's signal path can be as important as a cap change sometimes. The Path Audio's are very smooth and detailed. $30 for a resistor is high compared to $1 or $5, but compared to cap prices it's cheap for the results.
I think resistors are overlooked sometimes. Changing from a ceramic or Mills to a Path Audio resistor in the tweeter's signal path can be as important as a cap change sometimes. The Path Audio's are very smooth and detailed. $30 for a resistor is high compared to $1 or $5, but compared to cap prices it's cheap for the results.
Hi grunter !
Using Duelund Silver bypass especially on treble/midrange will make a clear difference,
speaking of own experience. 

Hi, I update the thread.
After opening loudspeakers and analyzing the tweeter and mid+woofer crossovers I decide to substitute the following components in series with speakers.
Tweeter crossover - Mundorf 6,8uF mcap, anonymous 22uf film cap and ceramic 1ohm resistor respectively substituted with 6,8uF Jupiter VT 100 Aluminium Wax Paper, 22uf Mundorf Supreme Evo Oil and 1ohm Powertron resistor. I have not enough space on the PCB for large 22uf cap, so I decide to go with Mundorf Supreme Evo Oil, good cost/quality ratio and, more important in this case, quite small.
Midrange crossover - Mundorf 100uF electrolytic cap, 2,2ohm ceramic resistors substituted with 2 Mundorf 47uF Supreme Evo Oil caps + 6uF Jupiter VT 100 Aluminium Wax Paper and 2,2ohm Powertron resistor.
Here the space and cost importance are even more evident, cause a 100uF electrolytic cap is very small and cheap than equivalent film capacitors.
The mid crossover has to be made, but I've already done the tweeter crossover changement: much more resolution and information with much less harshness and more natural sound.
Hi Ciao,I also have the Grand Callas.  Were you able to follow through on the mic crossover changes also?  Have you done any other changes to the speaker?Darin
Ciao mi chiamo Fabio vorrei informazioni sull'upgrade del crossover delle Opera Grand Callas.O magari condividere pareri.
Hi, I update the thread, excuse me for being late.

Here are the mods done and to be done.

Substitution - all components are in series with the speakers

1 cap 6,8 uF -> Jupiter VT 100 Aluminium
1 cap 22 uF -> Mundorf Supreme Evo Oil
1 res 1 Ohm -> Powertron FPR2-T218 Metal Foil Resistor 30W

1 cap 100 uF electrolytic -> 47 uF + 47 uF Mundorf Supreme Evo Oil + 6 uF Jupiter VT 100 Aluminium
1 res 2,2 ohm -> Powertron FPR2-T218 Metal Foil Resistor 30W
(to be done)
add 1 uF bypass cap on 47+47+6=100 uF caps -> Mundorf Supreme Evo Silver Gold Oil

Woofer (to be done)
add 1 47 uF bypass cap on 3x330=990 uF electrolytic caps -> Mundorf Supreme Evo Oil
2 parallel res 1 ohm -> Powertron FPR2-T218 Metal Foil Resistor 30W

As for now I could say the most upgrading mod is sobstituting the 100uF electrolytic cap with the 47+47+6 parallel caps of better quality, the mids now really shines as resolution and thruthfullness.

Dear @grunter : " the most upgrading mod is sobstituting the 100uF electrolytic cap... " crossover

agree, I experienced the same in my system where the woofer speaker came with an electrolytic 100uf.

I can see and read that you took the road/path to make the crossover mods in your speaker through a blend of high end/boutique caps As a fact that is the normal path for any audiophile that wants to improve the quality performance levels of his room/audio system..

As you I started a thread looking for advises of caps from audiophile experts for I can make my " last " speakers crossover mods and I was very specific on what I asked in my thread:

looking for HARMLESS and SIGNATURELESS caps that can preserves the sensible and critical signal integrity that was picked up by the recording microphones.

I received the normal boutique advises and suddenly I decided ( thank's to my thread and during/inside the thread. ) to make a " deep " research about caps through internet, from A to Z. What a learning lessons, for say the least.

Though that research and with out any Agon audiophiles advise I decided to test WIMA caps and yes you can laugh about and  decided to think " out of the box ".

Wima extremely humble and inexpensive caps were never in my mind its use, as a fact each time I seen a Wima in my system inmediatly I take off and changed it for a " better " cap.

Today and after first hand experiences with several diferent high end/boutique caps ( Duelund, Mundorf, V-caps, Jantzen, Sonicraft and the like. ) I know almost for sure that those added boutique caps colorations are only that colorations/distortions that does not exist in the recording but we like it and for me those " nice colorations " are not part of the real MUSIC, of what the recording microphones pick-up.
 We audiophiles are looking for those " nice " colorations/distortions because those colorations are the ones we are accustom to, not because we are sure are rigth.

Those colorations just does not exist in a near field live MUSIC listening sessions. Any kind of MUSIC. This is my reference to achieve my room/system targets.

Tidal 200K speaker is a good example on how a speaker manufacturer use those kind of caps as a " tone " devices " as a " tone control " when the main target in a speaker crossover capacitor certainly is not to be used as a tone devices it's not any cap function/role.

Tidal use a blend of 5 diferent caps in its speaker crossover to make exactly that:

I found out that WIMA was and is the caps industry standard, every industry kind: military, medical instruments, aerospace, aeronautic, audio. You just name it.

If you open any Soulution electronics you will see down there full of Wima caps. This is a board example of Soulution :

but not only on that high end electronic manufacturar but here too:

or in this Swiss made:

or this over 250K Rentless by D'angostino:

I know that you are done in your great system for now but I urge you that in the near future try change all your speaker crossover caps for the Wima MKP-10 caps that you can buy through Mouser supplier. My speaker use very similar caps values as yours: 6.8uf and 100uf.

I used 4- 22uf + a 10uf caps instead the 100uf one. Before I made the Wima changes I was using Jantzen Alumen Z and V-caps in woofers.

The overall quality level diferences ( beleive it or not. ) were and are nigth and day. I don't use any by-pass caps through the speakers crossover ( it does not need it. By pass does more harm than any improvement. ) and all caps are the same model no single blended cap filter.

As a job it's not an easy job the change of the caps for the Wima ones because the Wima are radial instead the usual axial termination conectors. Yes it could be a hard work more time consuming and care that other thing but the rewards makes that that work be worth to do it !.

Btw, in that circuit board Soulution link all those low brown resistors you can see there are Vishay-Dale and the Powertron resistors you choosed for your speakers was made by Vishay because Powertron is part of the Vishay group and Vishay for resistors is the industry ( any kind of. ) standard as Wima on the caps.

I'm using the colored Duelund resistors but I already received the Powertron too that I choosed over the boutique audiophile Pathaudio ones.

Regards and enjoy the MUSIC NOT DISTORTIONS.

Btw, from some years now the high-pass filter in my biam system was and is doing through the Levinson monoblocks ( heavy tweaked. ) at its input cap where the overall audio signal must pass ( all frequency ranges. ) and in combination with a Z-foil TX2575 Vishay resistor makes the first order high-pass filter.So this input cap is way critical for the system overall quality performance and I was using a V-cap Teflon Cu ( 100.00 each one. ) that I decided one month ago to change for the ridiculous humble Wima FKP-1 ( 2.00 ) and guess what: the Wima outperformed the Teflon Cu with an unexpected easy. Unbelievable ! ! .
Raul this is very interesting!
Thank you very much!
I have to experiment about it, as you said no one could think that Wima could be a good alternative to Mundorf, Duelund, Jantzen, Jupiter and so on, but reality is that audio have to be tried out.
Dear @grunter : "   audio have to be tried out. "

I agree and was what I did  with out take in count what the experts or any one could say about.

Many times problem is that we all audiophiles, some way or  the other, are " followers " and we just don't turn around our face/head to learn what the audio world can shows us other than those high end/boutique items.