'Bypass' caps have a following, too.
Caps in parallel add value, so if you need 3.6, you can use a 2.7, a 0.82 and a 0.1 equalling 3.62 which is 'over' but well within the tolerance.
The stock caps are probably 10% and the Clarity MR are 5% which puts you within design intent, even 'worst case'.
Looking at the picture of the board, the inductors are not in the best configuration.
ALL inductors should be at right angles to one another.....never parallel or coplanar.
The new caps will be GIGANTIC compared to the stock caps, so be ready. Look at the data sheets to get an idea how large the new caps really are and be ready to work with layout. Good idea going external, 'cause frankly, you probably don't have room IN the enclosure for the mods you have in mind.
Custom made caps? Not a bad idea, but I'll bet they cost $$$$ |
Bryon,
I don't have any experience with mixing caps from different brands. However, there's a lot of information in that Mundorf thread I mentioned. Those guys talk about mixing caps of different brands.
On 11/29/10 Undertow talks about his cap mix ratio a bit, but also mentions that there is no golden rule-of-thumb ratio.
On 2/1/11 Undertow responded to one of my questions, I have used the Duelund, Clarity combo, but found that 100% Duelund or Clarity were better in my case overall. As for the bypass with the Silver oils and the Clarity MR's that is the best mid cost combo yet I have heard consistently, and very organic with good dynamics never any edge. Also on that same date Face said that his experience was consistent with Undertow's.
My first choice in the various components we are talking about (capacitors, resistors, inductors) is Duelund. I used a Duelund VSF copper capacitor in my previous speaker project and loved it. The guys on the other thread have pretty much gone 100% Duelund CAST components, which is the blue riband of this arena. However, on my current project I don't have the budget to go with Duelund VSF copper, much less CAST. My goal with this project was to find the capacitor that those guys really liked before they went Duelund CAST, and that seemed to be the Clarity MR, so that's what I am going to try this time around. I also have access to a lot of tubes and will fine tune my system further once the crossover is in place.
I'm taking my crossover outboard this time and plan to use all Clarity MR caps and Duelund Cast resistors. I haven't decided on the inductors yet.
If you can get Clarity to build you a 3.6micF cap for you, I would do that and not worry about mixing caps.
Regardless of the caps you choose, I would recommend that you change out the resistors too and go with the Duelund Cast. If you don't have room for the Duelunds, I have used Mundorf M-Resist and thought they were fine.
Just another thought, if you have room for Duelund caps, I would not hesitate to go that route. CAST is the ultimate, but don't hesitate to use VSF. Write Frederik Carøe, he owns Duelund, and tell him that you need a 3.6micF cap and they will make it for you. Basically they make everything custom anyway, so it's no big deal. If you order it through PartsConnexion he'll just ask you to make sure they make a note on the order of the value you want. They may be able to adjust the size of the cap to fit in your space and the same applies to the resistor, they'll make it shorter than their standard 5-inches if you require it.
John |
Thanks Al. I will keep that in mind, in the event I can't find or special order a 3.6uF cap.
John - Do you recommend Clarity MR for both tweeter caps? What about mixing caps from different manufacturers? Any rules of thumb here?
Also, do you think I should replace the resistor for the tweeter? If so, with what? |
Do I simply place the leads from the two new caps into the same holes, so that each hole has two leads? I would guess, especially after looking at the pictures you provided, that two leads won't fit into one hole. But if you end up having to use two caps, I think it would be reasonable to first solder their leads together such that there is a short protrusion of one of the leads beyond the point where they join, and that protrusion could then be inserted into the hole. Best regards, -- Al |
Bryon,
I was just reading the white paper linked on the Madisound webstite for the Clarity MR caps. It mentioned that intermediate values are available upon request. You might be able to order a 3.6micF from them. That may be the same case for the Mundorf M-Cap Supreme too, but between those two, I'd go with the MR.
You can ask Madisound or PartsConnexion about it. Also, you might send Mundorf and Clarity an email and see what they say. But if you can get a 3.6micF cap made, that would be the way to go.
John
John |
Thanks, Al. I assumed the caps were uF, even though they are not marked as such. As this is my first attempt at a mod, I don't want to make a rookie mistake.
You are right that 1.8uF is a standard value, so connecting two caps in parallel might be an option. Do you know whether two caps can be connected in parallel to the crossover board, in light of the fact that the board has only one pair of holes for the stock 3.6uF cap? Do I simply place the leads from the two new caps into the same holes, so that each hole has two leads? |
Bryon,
I don't have the experience or confidence to change capacitor values, but that is an 8% difference you are considering. The Mundorf M-Cap Supreme line has 2% tolerance. You can read some reviews about caps at humblehomemadehifi, and also Google the Tempo Electric reviews.
I went to the Madisound website and looked at the Solen Fast Caps and didn't see a 3.6micF value. I assume that's what's in your speakers, but maybe Focal had them custom made, and if that's the case, they certainly must have considered that the best value for that tweeter. I wouldn't stray too far.
Here's a couple of options for you:
Option (1): M-Cap Supreme:
- two 1.8micF caps in parallel to give an equivalent 3.6micF value.
- single 6.8micF.
Option (2): Clarity MR w/ Mundorf Silver/Oil bypass caps:
- One Clarity MR 3.3micF with one Mundorf 0.36 S/O cap in parallel to give 3.66micF... (1.7%) but maybe that's okay, I don't know.
- One Clarity MR 6.2micF + 0.68micF S/O = 6.88micF (1.2% off).
I think the M-Cap Supreme would be an upgrade for you and you can maintain your exact values, but if the 1.7% and 1.2% differences are insignificant, some of the members on the other thread I referenced like the MR - S/O combination at lot, but others also report that they get the best results from having a single brand cap in the crossover.
If it were me, I'd do the M-Cap Supreme, it's a safe choice, maintains your exact values, and is a simpler installation.
As for the resistors, on the PartsConnexion website they have a 5.6ohm, 10W Duelund Cast resistor listed. Other than that, I'd go with the Mundorf resistor I guess.
John
P.S.: If you wanted to go all Clarity MR, you could do a 3.3 + 0.36 = 3.66, and then a single 6.8MR. |
Hi Bryon,
Yes, those are undoubtedly 3.6uF and 6.8uF. FWIW, though, I would not feel comfortable introducing an 8.3% error into the nominal value of the 3.6uF cap, especially in a crossover network that is designed, as this one appears to be, to have sharp slopes.
It might prove helpful to keep in mind that using two caps in parallel, where their individual capacitances sum to 3.6, would be a way of achieving the correct value. I believe 1.8uF is a standard value.
Best regards,
-- Al |
Thanks, Jeff. Just discovered this: "J" indicates a 5% tolerance, according to capacitor codes. In light of this... Is it a safe assumption that the 3.6 and 6.8 caps are 3.6µF and 6.8µF? Are those typical values for caps associated with tweeters? Also, finding a 3.6µF cap has been a little difficult. The caps I've found so far from various manufacturers are either 3.3µF or 3.9µF. I assume that using a different value will change the frequency of the high pass filter. Is that a bad idea? Or is the difference - .3µF - small enough to be ignored? Should I just keep searching for a 3.6µF cap? Anyone? |
J indicates value tolerance; I don't know what exactly 'J' means, but I"m sure someone does.
. |
Thanks, John, for your advice. I will take a look at the Mundorf thread. I don't know the first thing about caps, so hopefully that will help.
I think the plan at this point is to replace the 2 caps for the tweeter, and possibly the resistor for the tweeter. I am going to leave the inductors alone.
As far as the midrange, I may do that down the line, if I am happy with the tweeter results. But for a first step, I am going to restrict myself to the tweeter. With that in mind, I have a basic, possibly stupid, question as I look around for replacement caps:
The caps for the tweeter are labelled "3.6J" and 6.8J." Does the "J" after the number mean joule? In my preliminary search, all the caps I am seeing are rated in µF. I don't see any caps labelled with "J". Why is that?
Bryon |
Any opinions on the Cardas caps? |
One more comment though, after reading your cap values again it is the woofer values that are the really big ones. Maybe it would be okay to just replace the midrange and tweeter caps as it's the inductors that would play the more important role with the woofer. Others on this or the other thread should be able to provide you with a more solid recommendation however. |
Byron,
There is another thread on Audiogon which might be of interest to you, "Capacitor log Mundorf Silver in Oil." It's a long thread but it logs the journey of several members who ended up with Duelund Cast crossover components. Those are very expensive components and I am not recommending them for your project just simply because for your crossover the cost would be huge. However, that thread does contain a lot of their impressions of other components they tried along the way.
I was going to suggest Mundorf Supreme as a good capacitor, but upon reading the large values you have in your speaker, I'm not sure what to recommend.
I am doing another speaker project and plan to use Clarity MR caps, Duelund Cast resistors, and North Creek 10awg or 12awg inductors, but I don't have nearly as many components as you, nor such high values.
What are you planning to do with the inductors, and are you going outboard with your crossover?
John |
I have created schematics for the crossover. It was tricky at first, but easy after I got the hang of it. Here they are: TWEETERMIDRANGEWOOFERSThe following are the values of the caps and resistors for the various drivers, as labelled on the components: TWEETER C1 = 3.6J 250V C2 = 6.8J 250V R1 = 7W 5.6Ω JF MIDRANGE C3 = 56µF 63V C4 = 12µF 63V C5 = 4.7J 250V R2 = 10W 6.8Ω JF R3 = 10W 2.4Ω JF WOOFERS C6 = 220µF 63V C7 = 440µF 63V R4A = 10W 20Ω JF R4B = 10W 20Ω JF R4C = 10W 20Ω JF What's next? Bryon |
You can try another (more expensive ) cap as long as it has the same value and has the appropriate voltage of the focal one .
More expensive isnt always much better though and ive tried a lot believe me , duelund being the rolls royce of caps.
If you dont replace the same value you will change the intendid balance of the speaker.
I dont think there will be any manufacturer guarantee either.
mundorf is also good stuff , i use a silver / oil at the moment with the diamond tweeter . |
Ok, I will make a schematic diagram and report back.
Bryon |
Bryon, help us help you by tracing a schematic diagram of all sections of the x-over. It's really easy to tell you to replace all the film caps with other expensive film caps, but that does no one except the cap seller any good. If you think that's beyond your capability, get someone else to do it. I find it easier to start with the output sections, not the inputs. Since the output wires are clearly labeled, you have a head-start on the project.
. |
You may want to consider starting from 'scratch'.
Get a schematic even if you have to start tracing wires around.....
That board has (GASP!) 5 iron core inductors. In the Magnepan world of DIY, that is one of the first things to go.....change the iron core to an AIRcore inductor to eliminate possibilities of saturation.
Any series resistance changes can be made up using lower or higher resistor values.
Gotta have the schematic, first, though. Start tracing where the wires come TO the board from the amp.
Also, any new caps are likely larger than stock. It just seems to work out that way. |
I have removed the crossover from the speaker. Here is a link to the photos I took: Focal 1027 crossoverI don't really know how to interpret what I'm seeing. Any help would be greatly appreciated. Bryon |
Don't really have much of an idea what they are worth. The original MSRP was $8k. They were heavily discounted toward the end of their production run, when I bought them (new) for around $5.5k. That was roughly a year ago.
I looked at your outboard crossovers. Nice!
Bryon |
...and trace the MR section(s) too. Caps and resistors in series with that driver(s) definitely add bad stuff to and subtract good stuff from the music.
BTW what do you think your speakers are worth, generally?
Just tonite I finished the covers for the Avanti outboarded crossover boards.
http://i89.photobucket.com/albums/k220/jeffreybehr/Avanti%20IIIs/Overallfroml-rear_1280w.jpg
. |
Thank you, Jeffrey, for your advice. I will attempt to remove the crossover board and trace it, to determine exactly what parts are in the tweeter's signal path. It may take me a day or two to get the time to do it. I will report back when it's done.
Bryon |
Bryon, you need to remove the board and trace the schematic, at least for all devices connected in any way to the tweeter outputs. Then you'll know if you have a 1st-, 2nd-, or 3rd-order filter and if there are any resistors in the circuit, etc. I too would replace the resistors in the tweeter and MR circuits but would not replace the inductors, as they 'sound' the least compared with caps and resistors. For the latter, use Mills Wire-wound noninductive 12-Watt resistors; they're VERY reliable and sound quite good.
Do this in stages, Bryon, and help us help you to do it correctly.
I too would NOT use Solens except to replace 'lytics in the bass section.
. |
Thanks to everyone for your input. I have two principal concerns: the plan and the execution. As for the plan... You can see a picture of the crossover here. At the advice of another Audiogon member, I tested some of the caps on the crossover board to determine which one is associated with the tweeter. Here is what I did: I placed one lead of a multimeter on the lead of the capacitor, and the other lead of the meter on the tweeter's positive terminal. I got measurements of .4 Ohms and 4 Ohms for the two leads of the cap labelled "Focal 4.7J 250V" in the upper right of the photo. (I am assuming that the .4 Ohms measurement is really 0 Ohms, since I get the same .4 Ohms measurement when I simply touch the two leads of the meter together with nothing in between.) On the basis of these measurements, the Audiogon member I've been talking to concluded that the 4.7J cap is the one for the tweeter. I have no reason to doubt him, since he seems like an experienced guy, but I would like to confirm with other folks that we (mostly I) didn't miss anything. There is another cap on the crossover, labelled "Focal 3.6J 250V" that, when I performed the same test, came back with measurements of 1 Ohm and 10.5 Ohms. Could that cap have anything to do with the tweeter as well? Is replacing the one 4.7J cap all I need to do for the tweeter? Thanks, Bryon |
considering you will not make any incorect wiring after upgrade its very good idea- focal react to this upgrades very good. change caps in tweeter section ad resistor in tweeter atenuation section. if yo like to play speakers loud also change bass inductors to transformer types, or transformer foil inductors. just keep exact RDC |
Modifying crossovers can be very rewarding sonically. I'd suggest doing all the caps and don't forget to do the resistors.
As for what caps to use, there are many good choices to fit your wallet. Sonicap Gen I's are very good and reasonably priced. Clarity MR's are another good choice, but cost a lot more. I do not recommend Solen.
For resistors, Mills are most folks go to.
Pitfalls....make sure you have the room for new caps as most of them are going to be much larger than stock.
Some good reading, www.humblehomemadehifi dot com/Cap.html |
Yup; done this sort of thing often, most recently in a pair of Audio Physic Avanti IIIs. In those, the 2 caps in series with the tweeter were a 6.8uF and a 15uF. I replaced both with the highest-quality-composite cap I chose to afford, and this time I wasn't cheap. Altho the highest-value SoniCap Platinum (Teflon-film) cap Sonic Craft lists on the site is a 4uF, Glowacki had a pair of preproduction 6.8s, so I bought and installed them, and the 15uF turned into a 12uF SoniCap Gen.1 'propylene plus a 3uF Platinum. (Claity Caps were original.) Altho I'm no golden-eared audiofile the way some of my friends are, I heard MUCH-cleaner and less-edgy treble, so much so that I was able to increase the average level of listenable treble several dB. I suggest a combination such as I used or perhaps with as high a value of MultiCap RTX you choose to afford with a SoniCap Gen.1 to fill the value to the original.
What is/are the value(s) of the tweeter cap(s)?
BTW, then it's the midrange's turn. :-)
. |
