Tweeter Capacitor Upgrade (Coincident PREs)

Hi all, looking to upgrade the Solen 4.7uF 100V caps that filter the low frequencies out of the Accuton tweeters on my Coincident PREs.  Started by looking at Duelund's, but PartsConnection doesn't even list prices for a lot of the models (or is out of stock) at that value... that motivated me to try and collect some impressions from the group.

Apparently Isreal is using Mundorfs in that position at this point.

As always, thanks for the input.
52dc3b0a 7875 49c3 80f0 43cd1076b7e0cal3713
Hey cal,
Mundorf Supreme has a particular house sound. Scintillating to over-saturated color. Magico uses them extensively, as does the top end B&W.

Otherwise, if you want something more natural and open, Clarity CMR to Jupiter Copper foil is the range I normally recommend.

Try the Clarity CMR with a small (0.1) Audyn TruCopper or Jupiter copper film as a really great low cost compromise.

The best way to find caps right now at Parts Connexion is to type the value into the search window:
and you'll find everything they have.


Thanks Erik. Also, just to be doubly sure. I don't need to worry about voltage rating as long as I meet or exceed the original value (100V), right?
Right. You could probably even go lower, but hard to find a film cap any less. :)

Of course, higher voltage = higher cost, so watch out!
Have you thought about using paper in oil caps?
I am partial to the Jupiter Copper Foil.
To me the Audyn True Copper can be just a little tilted in the upper mids.
The Jupiter Copper Foil paper and wax is my Favorite,although not cheap
Another vote for Jupiter.
Geta2ay from plastics like a Mundorf s ownedtheir Best Silver Gold oil supremes several times . TheJupiter Copper foil 
muc more natural and meaty once you give them 300 hours,
and a Duelund. Silver foil ,oil.01 Bypass cap really opens the top up . Solen is junk,  depending on budget .
go to humblehomemadehifi capacitor test.   A solid A recommendation I usethem myself in my speakers .whileyou are 
at it rebuild the whole Xover austral bloom uses Nothing 
remotelyhigh quality .i owned several  amps speakersall economy 
parts .I modded them  myself , a Huge difference , and for suerewire them , I just used VH Audio New AWG 21 for the tweeter, awg15  forthe other drivers a Litz ssmall diameter 
OCC - 0 crystalCopper verythinned foamed Teflon dielectric  
fantastic wire . He sells a awg 12 and awg 11 forLoudspeaker cables, and use Copper get rid of the junk brass ,on the terminals 
not natural stall I changed every connection throughout to copper
at lesst a 10% improvement . I used the exsctwiring for my amp-preamp, Loudspeakers also. The whole system .time consuming and maybe $1500 in wire but the results are substantial.
i think isreal uses his top of the line statement cabling inside throughout for his PRE i dont think youd need to upgrade the wiring inside. dont know about the caps.
Here is my thinking:

4.7uF :
Clarity CMR : $54
Jupiter CF: $265

Jupiter CF: $63

Audyn : $20 (Parts Express)

So somewhere in there I think the OP can find a fine solution. :)

Thanks for the recommendations everyone.

@justanotherhifiguy Isreal states that they use Mundorf in current models of the PRE, but my pair (I purchased used) just have Solens.  The frankenstein amps also have solens throughout... although to be honest I tried replacing with Duelund and didn't like the result.  

@erik_squires Lots to think about in there... I'm very torn.
@audioman58 And fortunately there's nothing else really to change.  The PREs only have that one 4.7uF capacitor on the tweeter.  The midrange is directly wired to the binding posts and the the bass just has a single inductor coil.  
for sure change the binding post which are Brass to a Furutecor WBT next gen Gold over Copper ,and put in a Quality Wire the tweeter and mid are connected to. The inductor to create
the Xover ,and you can put in a much better inductor 
to a awg 12  Jantzen inductor far better especially for the Bass
i would think there is another inductor there somewhere as well as resistors, pull out the midrange and woofer you will see other things hiding in there. I have found that to be true case up grade 
the resistors Path Audio, the best if parts connecxion has them in stock, Ohmite Gold, Mundorf Supreme, or Mills 
resistor ohms rating on the resistor. It’s up to you.
best of luck  and use a good soldering station recommend at least 
80 watts and Cardas,WBT, Johnson’s, or Mundorf Silver Gold 
minimum of 5-5% silver solder content Cardas has. Flux built in
which helps a lot  to clear and bond surfaces.
In my extensive use of capacitors in components meaning DAC, preamp and power amplifiers, but not in speakers, I find the best capacitors are V-Caps (Oil & Copper versions).  I find that the Jupiter copper caps have an emphasis in the mid-range.  They have a very musical sound but the mids standout at the expense of the other frequency ranges.  Just more focus in the mid-range.  One of the manufacturer of panel speakers that I partner with also used the Jupiter caps and when I told them to try the V-Caps, they were surprised how much the sound staged opened up with greater detail and separation of vocals and instruments.  Another Audiogoner had Jupiter in his preamp and he herd the V-Caps in the components that I build where we swapped out the caps.  He heard the differences and decided to try the V-Cap coppers in his preamp versus the Jupiter capacitors, he also noticed the same advantage.  BUT it comes down to the sound you prefer and you also may have to try both to see the benefits in your own system.  Happy Listening.
@cal3713 Another vote for the Jupiter Coppers in your application as a cap to be placed in series with the Accutron tweeter.   I used the Jupiter in my Coincident Super Victory II for that application with a Duelund Silver by-pass, and could not be happier.  In the end, all we can do is guess.  The good news here is that it is not hard to improve on the Solens, but no one can tell you for sure what the "best" cap for your application is going to be.   Just be aware that the Jupiters are painfully slow on break in.  They oscillate between really good to really bad for at least 120 hours, maybe 200, and apparently it is common for them to require 400 hours to completely stabilize.
@audioman58 I am also perplexed by the crossover design in the PREs.  I don't know what one might find in the woofer cabinet, but since the preferred wiring arrangement is a direct connection from the monitors to the amps, with a second set of cables running to the woofers, and since the monitor enclosure contains only one crossover in series with the tweeter, I must surmise that the midrange is being run full range.  It would seem that the midrange is truly crossoverless, with no inductor or capacitor in series or even in parallel.  When I rebuilt the crossovers on my Coincident Super Victory IIs, I chose to stick with the stock Solen 12 and 14 gauge inductors.  I don't regret the decision, but of course it may have been possible to improve upon them.  I think the big bang for the buck here is going to be in swapping out the tweeter cap.  The PREs are already superb, in my humble opinion, speakers.  It may not take anything more to get cal3713 where he wants to be. 
I wonder how the PRE would sound with some paper in oil caps? It only uses two so it wouldn’t be that hard of a mod?
Do not willy nilly change coils!

You have to match the DCR or you can make fundamental changes to the tone, and not in a good way.

For the woofer coil DCR sets the bass level, as well as helps with baffle step. Meaning, you must measure the DCR and only replace with equivalents (within reasonable tolerances).

In parallel to the driver, changing DCR without adding R can really muck with the impedance curve and have unintended consequences.
Good article on capacitor comparison and listening tests.
My speaker manufacture uses extremely tight tolerances so as Erik mentioned above just the differences in tolerances can shift the cutoff frequency substantially. One of the reasons I chose the capacitor I did was tight 1% tolerance along with excellent sound for expense ratio. I am a Mundorf Supreme Silver Oil guy myself for preamps and Supreme in speakers.  Paper in oil capacitors typically have 10 to 20% tolerances. So do pay attention to attempting to get a reasonably tight tolerance match of the capacitor you are replacing.  I have had good experience with Sonic Craft as a seller, large inventory, good prices, fast shipping and they do capacitor matching for a minimal fee.    

Warning: Do not measure capacitance value when tweeter is still in circuit. To duplicate its value precisely, I measured the capacitance value before I ordered replacement. Since the capacitance meter puts a signal out to measure capacitance value it can fry you tweeters! Don’t be a dummy like me, remove the capacitor from the circuit. My mistake cost me a few hundred bucks; however, I was able to replace the ribbons later and now have a spare set of tweeters. I am good with my mistake now, but when I looked at my tweeters and saw those shredded tweeters I was kicking myself.

I agree with Erik you only change inductors if you have the correct 
inductance reading or label on the inductor. The Jantzen Copper foil waxed paper inductors are a great buy and close to the best out there .wiring cap, for sure better Gold over Copper Connectors 
vs the stock Gold over Brass ,4x the conductivity ,
And  rewire it with a Quality Wire ,Supra awg 13 ,and 15 
is a Huge upgrade then the Coincident Wire at less then $3 a ft Madisound.
Agree with advice regarding the inductors, you can easily degrade the sound quality if not sure of specific specifications. Thread carefully. 

Don't agree with advice to rewire as the internal Coincident wire is very good quality. 

Brownsfan (Bill) nice approach for your tweeter capacitor. Some folks don't like to use bypass capacitors but happy this solution worked for you. I went Duelund CAST copper foil capacitors at the tweeter. 5 years later I remain  very pleased with the improvement. Did you consider changing the internal wiring? I sure didn't. 
@charles1dad, I did not consider replacing the internal wiring.  I have used Coincident wire externally, and found it to compare well with a few other options in the same price range, so I didn't think it would be an experiment with a high probability of success.  I did use a few inches of Duelund Tin/Copper here and there where I needed to make things work, as there was nothing extra to work with.  I also did not consider replacing the binding posts.  I spent ~ 1200 on the project, and don't feel compelled to go any further.  I am more than pleased with the speakers as they now stand, so at least in my case, going further might well be diminishing returns.   

The op is starting with speakers that are several levels better than my super victorys in stock form.   I think replacing the solen cap in the PRE is a no brainer, and would advise he start there and proceed slowly.   I suspect the Duelund by=pass caps might give the accutrons a bit too much resolution.  They are not lacking in air and extension even with the Solens, and he could end up with a hyper detailed presentation would be my concern. 
Hi Bill,
As usual you've made wise and very rational decisions,  binding post for example.  No good reason to change the Coincident binding posts. They're pure solid copper as opposed to the typical utilized brass posts
Charles .
"I suspect the Duelund by=pass caps might give the accutrons a bit too much resolution. They are not lacking in air and extension even with the Solens, and he could end up with a hyper detailed presentation would be my concern."
It works opposite.
I put Duelund Cu-Sn bypass (in my Altec 604E Werner Jagusch Crossover) bypassing old vintage oil capacitor.
As result a lot of music that sounded bad before started sound good.
After that I replaced old vintage oil capacitor to Duelund RS capacitor with the same bypass Duelund Cu-Sn capacitor. It gave me big improvement in transparency and musicality.
After that I exchanged Belden internal wire to Duelund 16AVG Cu-Sn wire. I can say this wire is magical.

Let me know if you want to buy Jupiter caps. I have different values than I would like to unload.   
Thanks again for all the conversation... All very useful.
At this time, I am not really inclined to do anything besides replace the tweeter capacitor, but clearly there's a lot to think about there.  I think improvement there is highly likely, but I'm a little less confident about the wiring/inductor/post changes. My soldering skills are improving, but I prefer not to touch what I don't have to.

And in regards to some of the conversation, I've looked inside the speakers and indeed, the only cap is on the tweeter. The mid-range is connected directly to the binding posts, and I'm pretty confident that the only component inside the subwoofer cabinet is the large inductor coil.
Your PRE speaker crossover is pretty simple (fewer part count) and straightforward compared to many other speakers (higher part count). Your instincts are right IMO. Upgrading to a very high quality tweeter capacitor is a very worthwhile single modification. It sure worked out well for me and Bill(Brownsfan). I’m with you in your caution regarding the wire/inductor/binding post. There’s always something better to change to, but these stock PRE items are quite good quality as is. The stock Solens is a 'decent (not garbage) capacitors but is easily bettered.
Dammit.  The Jupiters are sold out at both PartsConnexiion and SonicCraft.  PC does have the Duelund RS Copper Foil caps, but I think you all talked me into the Jupiters... 
Psssst ....
Do a CMR with a Jupiter bypass cap. :)

Ha.  I added them to my cart but didn't buy yet.  Very torn about the process.  I suppose experimenting isn't too bad, especially at $55 a cap for the CMRs.  I just worry that I'll fry my tweeters if I play around too much.  Would much rather solder once and be done...
You'll be fine. Just don't solder too close to the cap body.
Not so much worried about the capacitors as the accutons... they have such tiny little tabs, so little room for heatsinks.
Talked me into it Erik.  Also gives me a chance to play some more in the future if I decide to buy some Jupiters or Duelunds.
@erik_squires I’m completely rebuilding my XOs. I have CSAs on the coax board and am comparing with and without Multicap RTX bypasses (~1%). I might also try a CMR bypass. Please characterize for me the SQ of Jupiter as a bypass. Thanks.
Hey @beetlemania
The CMR are excellent caps as mains, but above 4.7uF or so they need bypass caps. Below this, I can’t hear any benefit at all. The CMRs are really excellent caps.

My main speakers use a 3rd order hi-pass filter. To my ears, bypassing the larger cap (~ 10uF) they sound less compressed and more natural. I’m afraid it’s been about 2 years since I did this experiment.

@cal3713 Be aware that the CMR caps are physically huge! You don’t want to mount a 20uF directly to a speaker tab.

May be worth it to get some Duelund jumper cable too.

I'm thinking about upgrade of a second order LP filter capacitor  for my mid-bass driver.
I know the quality of inductor is very important for second order LP filter.
How much a quality of the second order LP filter capacitor does influence on sound quality?
another vote for Jupiter or Jensen copper foil caps. great caps in a reasonable price range. The Duelands are nice, but physically too large to fit in most apps, unless you build an outboard cross over box.
Just an update. I did install the clarity cap cmr with a silver duelund bypass. A really nice improvement from the stock solens (Israel actually claims that stock is mundorf)... Much smoother and cleaner. 

I also found some Jupiters and will try them out in a week or two as well.  Apparently there is very little stock at the large values. I had to have them shipped from England, and they only had 4 in stock. Soniccraft said they may never get that value back in stock.
How much a quality of the second order LP filter capacitor does influence on sound quality?


Based on my reading, this can be more important than the coil, even though it is in parallel. Especially if the original is an electrolytic, replacing them with even a modest film cap like a cheap Axon or Solen or Mundorf bipolar is going to be a bigger improvement than changing the coil.

Also, changing these caps is a little dicey, especially if replacing 1980's or earlier speakers, the ESR was pretty high and changes need to be compensated for. If you have relatively recent speakers (2000+) you should be fine.

Hey @cal3713
What value Duelund did you bypass with?

Audin True Copper 2.2uf -$74.18 (Parts express, commercial sales)
@bache what is your point??
Hi @erik_squires ,

Thank you for advice.

I have Altec 604"E" with Werner Jagusch Crossover.
This crossover use vintage German oil capacitors.
I already replaced HPF capacitors to Duelund RS 3.9uF bypassed by Duelund Cu-Sn 0.01uF bypass capacitor.
But for 8uF LPF capacitor Duelunds RS are out of of my range.
I want to try something like Jantzen Alumen, Z-Cap or Jupiter VT.

Today, I tried to bypass vintage German oil capacitors 8uF with Audio Note Copper 0.22uF. The sound cleaned significantly from midrange to bass. Bass became much more firm and focused. Vocals became a little bit less lush but still OK.

I’m a big fun of Duelund capacitors sound. Which of mid price capacitors can you recommend? I need sound as much as possible close to Duelund Custom Cu or RS signature.
Old capacitors ESR shouldn't be an issue, because I can adjust HPF cutoff frequency by potentiometer. (The crossover HPF has serial capacitor and auto-transformer. The input of auto-transformer is shounted by potentiometer) .

my point is just clarify that Audin get different line of quality and you mention $20 for 4.7uf. this is not price for   True copper line, max capacitance for this line is 2.2uf i   is good enough for tweeter crossover.
i am using in my loudspeakers 0,47uf value, and i recommend   and 
suggest to use this particular brand.    
hi @bache,

Sorry, I meant to say the Audyn TC 0.1 uF was $20, and I was recommending it as a bypass.
For bass caps, you can seriously go cheap. :) It's still a huge improvement.
Old capacitors ESR shouldn't be an issue, because I can adjust HPF cutoff frequency by potentiometer.

In shunt caps this can have really bizarre effects, so I doubt it. :) Depends very much on your amp.
hi guys i know this isn't related to the thread topic but i don't feel like making a new thread ... should i seriously be considering coincident pre? i live close to isreal so auditioning is no problem... i had a bad experience with him in the past but my line of thought is i shouldn't let emotions get in the way of owning what is potentially a rock solid speaker that would push above its price point.

i was considering the pre vs wilson audio specalties sasha daw, avantgarde acoulstics duo xd, and maybe kef reference 5. possibly a used jbl d670000... theres been a few for sale for under $40k.
ive also considered a few active systems but i dont think here is the place to ask about those types.
Let me add a little:
If you mess up the 2nd pole in the low pass filter, you can drop the impedance through the area above the crossover point, which actually doesn’t change your LP frequency response very much, but if your amp has very much output impedance at all, it will drop the output. Weird right? Seen it 2-3 times.

If you use a crossover simulator, you'll see this in the impedance graphs, but not the frequency response graphs, unless you have one that lets you simulate amplifier output impedance, then it's super obvious.

Hi @erik_squires ,

I get it. 

With bypass I noticed that vocals, saxophones and acoustic guitars sound not as smooth and tonaly reach as it was without bypass. It seems it cause a deep in lover mid range.

I think that vintage oil capacitors should be replaced by something that have a natural tone. I don't want to use cheap Solen capacitors. They sound too synthetic. I avoid to use them even for tube amp power supplies.