Kappa 8 Crossover ReCap Steps

@willy440 Sorry for the late response. My alert preferences were not set correctly.

Xover removal: As I recall now, I also had a hard time removing the xover from the K8 even after all the through bolts were removed. After removing the woofer and all stuffing I had to use a small putty knife and tap it with a small hammer from the inside of the speaker to "cut" what was holding it. It wasn't that it was intentionally glued but I think when Infinity put these speakers together they did not allow sufficient time for some of the varnish or xover glue spillover to fully dry. Use one of those flexible thin putty knives that will bend.

Capacitor replacements: My intent was to do a full refurbishment of my working K8 speakers, not to fix any specific problem. That is a personal choice based on how much time you have and if you are approaching this as a "fun" project or just want to fix what is broke and get out.

EMIT Diagnosis: There are TWO fuses. One for the front Emit and one for the rear Emit. They are on the underside of the xover board. How did you get to them to measure them if you did not remove the xover? There is no way around it you have to pull the xovers out an start doing some continuity tests on the rear Emit wiring to find where the problem is.

Quick Fix: One quick and easy fix would be to simply rewire the rear Emits to be in series with the front Emits. If the front fuse can handle both Emits that might get you where you want to get without major surgery or refurb.
 
For our story...
The back crossovers do come out fairly easily, although at the outset they appear to be really stuck to the speaker cabinet. Some gentle, continuous force pulling the crossover towards the front of the cabinet, and then a putty knife pry did the trick.
Once out, the C3 capacitors measured at about .006 uF... about 1/500th the value they should be. Replaced them, and the rear tweeters are restored.
We still don't understand why both caps failed (opened up), at the same time.
 
Miamiboy,
Thanks for the great thread.
Both of the emit’s on one of my Kappa 8’s don’t work.
Are the tweeter caps the black ones that are easy to get to without opening the crossover up?
I’ve tried jumping them and cleaning the tweeter control pot and that hasn’t worked.
I’m wondering if the fuses are bad, but I can’t see them. Do you have to separate the crossover to get to them?
Thanks,
Nick
 
A few weeks ago, in another post I said I was about to recap my recently purchased Kappa 8's and would post some notes and pics for the possible benefit to anyone else going down this path.

Below are some pictures and a PDF of an Excel sheet I used to document all the existing capacitors and the new capacitors. All replacement capacitors were purchased from either Parts Express or Madisound.

The biggest challenge with the Kappa 8 crossover is it has a two level crossover board design with the top board being a PCB. The PCB board sandwiches a number of capacitors and you can't get to them unless you detach the PCB board from the lower board to open it up. In addition to the screw posts that secure the PCB to the lower board, the PCB is also soldered to the four speaker terminal posts (two posts for low pass and two posts for high pass) that are hard pieces of wire soldered to the terminal connections on the PCB. The inductor wires (white) that are soldered to the board are too short and have to be removed to open it up even after cutting the speaker terminals and removing the screws. But this is the only way to get to the sandwiched capacitors.

So yes it is a pain and even if you wanted to put it back together just as you found it would be a problem because many of the newer, better capacitors are bigger/fatter than the originals and won't fit!

What I did was remove the four hard speaker terminal wires and replaced them with four long wires. I also added additional wire extensions to the white inductor wires. Then I could access all the capacitors and when done could close it back up with locking plastic wire wraps. I put a piece of foam in the middle when I snugged it all back together. One advantage of this is that if I ever decide to go back and replace any other capacitors, it will be much easier to just cut the plastic wire ties to open the crossover up.

I did not cut the wires from the crossover to the speakers/drivers and remove it completely. I used the speaker as a work bench being careful to cover the wood and placed Tupperware covers over the Polygraph and Polydome drivers to protect them while I worked.

I have only done one speaker and am now doing A/B listening comparisons. Immediately I noticed that the mids and highs are more "present" and clear. I did not change the low end capacitors. My experience with other crossover upgrades is that it takes some time for the new capacitors to "open up". So I will continue with the A/B listening comparison for at least a month.

Below are the pics and PDF. Only one of the tweeter capacitors did not match the schematic spec, as noted in the PDF, but all others were spot on.

PIC 1 is what the crossover looked like unmodified. Red arrows show where the speaker terminals are soldered into the PCB board.
PIC 3 shows the modification to the speaker terminal connection using new wires. Also note the white plastic tie down posts that I glued to the lower board so I had something to run the plastic wire straps through. The PCB board already has a number of holes in it so it is easy to put plastic tie downs through it to snug it down.
PIC 4 shows how the crossover can be opened up to work on. This pic is before I replaced most of the caps.
So all of the blue capacitors you didn't change because why exactly?
Are they all oil field and unnecessary to change?
Or is it because changing them won't really make a difference in the low end?

I recently did another set of ohm C2 speakers with the German made Audyn caps..
And it would be nice to have a couple of different sets of complete crossovers with Dayton, jantzen, mundorf, clarity cap, brands and do quick crossover changes just to see which of all of those would sound the best.

I hate that it is such a mysterious thing to figure out which would be the all-around winner of the different brands of capacitors.

One thing I'm fairly certain of is that Dayton caps are just a good sure bet to do the job.

And I have no complaint with the Audyn caps other than they don't offer a 4.0 & a 20.0 uf in the red series
 
So all of the blue capacitors you didn't change because why exactly?
Are they all oil field and unnecessary to change?
Or is it because changing them won't really make a difference in the low end?

You are quoting a post of mine from 1/2015 on those Kappa 8's. I have since sold them. There is a PDF in the original post that shows the parts I replaced. The only caps I did not replace as of that posting were the caps in the woofer xover which I latter went back in and replaced. They are marked NPE (non-polar electrolytic) in my parts list and in the K8 technical schematic sheet. This was one of my first Infinity recaps. For the woofer caps I used something not expensive from Parts Express, likely Dayton Caps because they are large values.
 
...And it would be nice to have a couple of different sets of complete crossovers with Dayton, jantzen, mundorf, clarity cap, brands and do quick crossover changes just to see which of all of those would sound the best.

I hate that it is such a mysterious thing to figure out which would be the all-around winner of the different brands of capacitors....

I did something similar with my Acoustic Research speakers. I've recapped several different pairs of AR's, using different brands of capacitors on each. Mainly out of curiosity, to see if I could hear any differences?

First off, my AR-1MS small satellite speakers. A small 2 way. I used Dayton 5% film caps, on the woofers and tweeters. They sounded very good after. Somewhat rich and mellow. Good soundstage depth too. But occasionally, a little spitty and sibilant. So, I added some Dayton Film & Foil bypass caps, which cured the issue.

Next up, a Craigslist find, a pair of AR58S dome mid 3 ways. Already very nice sounding, even with old stock NPE's. As such, I used ClarityCap ESA and CSA caps on the dome mids and tweeters. Shunt caps were Bennic electrolytic. The Clarity's took a bit of break in, before settling down. Dark and closed in, in the upper mids at first. Eventually, they opened up. Warm and relaxed, with decent detail. A wide soundstage, but maybe not as deep sounding as the Daytons. Very musical.

Finally, my big AR90's. On those, I went all out (for me, at least). I used Mundorf film caps. All the series caps were Mundorf EVO Oils, and on the dome mids and tweeters, I added Mundorf Supreme caps, where I needed to parallel caps, for the correct values. The lower midrange used all EVO oil. Shunt caps were Axon film too. The 350 uF bass cap was a Mundorf E-Cap and an Axon film in parallel.

To me, the Mundorf's sounded best of all the caps I tried. Maybe not as warm as the ClarityCaps, but clean, clear, and detailed. Not bright, just very low coloration. To me, very transparent. Music much more present. More palpable. Even my son commented that the old stock caps sounded distorted, with a slight static distortion in the sound, compared to the Mundorf's. They need more break in, but I'm still refinishing the 90's. So, more listening time later.

All the film caps sounded good. Much better than worn out electrolytic caps. Though, each did have a different sound signature. None that I wouldn't use again. Though, I do want to try Audyn caps one day. Maybe if I find a air of AR9's?

Oh, all of my AR speakers use the same 0.75" dome tweeters. The 3 ways use the same tweeters and mids. The same gear was used as well. I think that makes my comparisons valid. Hopefully, others will feel the same?
 
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hey Miamiboy, greetings from Delray Beach!

do you happen to have any notes on your kappa 9 refurbishment? I have a pair that I've sent the woofers and polydomes out to millersound to refurb.. stained the cabinets black and am now about to tackle the crossovers.. what brand caps did you use? I've had good success with sonicap in the past but I haven't gone through the kappas yet to see how much money it will cost to use them being there are so many caps.

thanks!
 
hey Miamiboy, greetings from Delray Beach!

do you happen to have any notes on your kappa 9 refurbishment? I have a pair that I've sent the woofers and polydomes out to millersound to refurb.. stained the cabinets black and am now about to tackle the crossovers.. what brand caps did you use? I've had good success with sonicap in the past but I haven't gone through the kappas yet to see how much money it will cost to use them being there are so many caps.

thanks!

Greetings Strohkin. Welcome.

When you recap your Kappa 9's, use poly on the series capacitors, and then use electrolytic caps for the parallel caps that tie to ground. Less expensive that way, and you still get the benefit of using good caps on the mids and tweeters. You can find a crossover schematic at Infinity-Classics.de. And, check out Parts Express for capacitors, but also Parts Connexion and Sonic Craft. They often have sales on parts.

Oh, good choice on Millersound. Bill is the best. And as for cap brands, Arnie Nudell thought Mundorf was a good brand for refurbs. It was what he told Paul McGowan use on his IRS-V's.
 
hey Miamiboy, greetings from Delray Beach!

do you happen to have any notes on your kappa 9 refurbishment? I have a pair that I've sent the woofers and polydomes out to millersound to refurb.. stained the cabinets black and am now about to tackle the crossovers.. what brand caps did you use? I've had good success with sonicap in the past but I haven't gone through the kappas yet to see how much money it will cost to use them being there are so many caps.

thanks!

I have been focused on other things, not receiving notifications and just happened to stop in and saw my alerts. How is your xover refurb coming along?
 
Thank you @StimpyWan!

yeah I've used sonic craft before to order parts. I'm still wrapping my head around intricate crossovers like these kappas, I'm not 100% sure what you mean about the series and parallel caps that tie to ground. to clarify.. I do understand the difference between series and parallel but I didn't know the crossover had both.. is it safe to assume the 12 inch woofers are in series (as you said don't spend big here/not as much of an improvement as the higher frequencies) and the other 5 drivers are in parallel?

when I removed and sent out the woofers to millersound I took a peak at the crossovers and saw the humbling mess of a crossover, I started to wonder about just removing the factory board altogether.. being that its not going to be possible to have it go back together at all the way it came apart..then I saw another fellow on here bradmich or something of the sort do exactly that.. turned out real nice.

hey @MiamiBoy!

I have not pulled out a crossover yet to open it up and start going through the values to compare it to the schematic.. I've read not always are they the same so I want to make sure before I start gathering a parts list.
 
I'm not 100% sure what you mean about the series and parallel caps that tie to ground. to clarify.. I do understand the difference between series and parallel but I didn't know the crossover had both.. is it safe to assume the 12 inch woofers are in series (as you said don't spend big here/not as much of an improvement as the higher frequencies) and the other 5 drivers are in parallel?

If you look at the crossover schematic, there are a number of capacitors in line with the drivers. Those are the series capacitors. They are C1, C2, C3, C4, C5, C6, C8, C9, C10, C11, C12, C14, C15, C16, C17, and C19. They have the greatest affect on sound. C7, C13 and C18 tie to ground. They are the parallel caps.

Another thing, 7 of those series capacitors use bypass caps. Some are already poly with a bypass (PP), and some are electrolytic (NPE) with a poly bypass (PP). The schematic is very descriptive in showing this. You should follow that same layout. But, you could buy a single capacitor, that matches the same values, as the bypass bundles. Up to you? It'd be a little cheap, but maybe wouldn't sound as good?
 

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wow, thank you @StimpyWan that is very helpful. I appreciate you taking the time to help me! I remember reading in the past a discussion about choosing the way infinity did it with both npe and pp or going completely poly for the sound quality.. it is to my understanding that people prefer poly for sound, but they get expensive and huge in size. I will probably keep the dual design but maybe go higher in value for the polys while dropping value for the electrolytics to stay in spec.

I also remember reading awhile back that people are removing some (fail safes?) in the crossover that can cause more hindrance than benefit provided your amps can handle the load. if my memory serves me right they said there are five in the design? do you know anything about that?

again, thank you so much for your help!!
 
Mixing NPE and poly saves cost and helps improve the sound of the NPE. An all poly cap is better, but a NPE and a bypass cap can sound very good for the price. Then, maybe large value poly caps weren't as available, or too expensive? Now, you could use a single 82uF Audyn Q4 cap, in place of C14/C15 and only spend $20 for the single cap.

As to fail-safe measures, the Kappa 9's used 3 different polyswitches (circuit breakers). A .85A-30, a 1A-30, and a RDE050A. If you have a very good amp, that provides clean unclipped power, you could remove the polyswitches. The same with the 1N5338B and 1N5343B diodes. Just there for extra protection. Small value resistors (around 0.1 to 0.2 ohms) could replace the polyswitches. A 12 watt Mills resistor would work and sound good. The diodes could be replaced with bus wire. All of these protection parts could also be left in place, but I would replace all of them with new parts, as polyswitches can wear out.
 
that all makes sense! that just about completes my concerns of pre-teardown. I am now much more. confident in tackling this! thank you StimpyWan.

do you have a set of 9 kappas yourself? you sure know your way around them! I currently have an Adcom GFA 555 II to use for the mids and highs and a Behringer Europower EP4000 to use for the woofers. I hope that will be enough until I can get my hands on a McIntosh or the like in the future.

oh one more question! when selecting replacement capacitors, what's the general rule to stay within for values? for instance you stated you can use an Audyn 82uf for c14 and c15. the diagram shows the values at 80. I understand 82 is close enough to not make a difference. just curious to know when is close enough no longer close enough? is there any rules like you can go a little over but not under?

for instance (given my crossover values are actually what shows on the diagram) looking at c9 and c10 = 20uf. and c11 and c12 = 23uf. would you use an Audyn 22uf for both of those or would you use a 22uf for c11 and c12... and maybe an Audyn 15uf plus a 4.7uf for c9 and c10?

sorry if I'm being petty. I just love to learn and know the most I can!

I also saw bradmich installed a Jantzen 6540 13mH 12awg c coil inductor in his crossovers. his theory is sound to me that it will make a difference compared to the factory 20awg inductor. but at 115$ a piece and two are needed for the pair.. that's getting pricey! do you think sonically that's worth it to spend for the low frequencies?
 
that all makes sense! that just about completes my concerns of pre-teardown. I am now much more. confident in tackling this! thank you StimpyWan.

You're welcome!

Just take it slow. Map out all the parts you want to buy first. And be prepared for capacitor shock. New polypropylene caps might be bigger. Especially if the voltages are higher on the new caps. You may have to mount them inside the cabinet and wire them back into the crossover.

do you have a set of 9 kappas yourself? you sure know your way around them! I currently have an Adcom GFA 555 II to use for the mids and highs and a Behringer Europower EP4000 to use for the woofers. I hope that will be enough until I can get my hands on a McIntosh or the like in the future.

No, no 9's. I have Infinity Infinitesimal 0.3's, RS6's, RSe's, and 6.1's. Plus a lot of others. Lot's of recaps too.

Be careful with power. Biamping is a good idea, as it helps balance the load, as 9's have nasty impedance dips in the treble and the bass. A Mcintosh with autoformers is a good solution too.

oh one more question! when selecting replacement capacitors, what's the general rule to stay within for values? for instance you stated you can use an Audyn 82uf for c14 and c15. the diagram shows the values at 80. I understand 82 is close enough to not make a difference. just curious to know when is close enough no longer close enough? is there any rules like you can go a little over but not under?

I try to match capacitor values as closely as possible. I even buy matched pairs of caps, whenever possible. Both speakers will match together that way. Keeping within a 5% tolerance to stock is normal. Over or under. Don't worry too much, as modern caps have tolerances of 5% or less. Many, 3% or less. Voltages can be higher, just not lower.

for instance (given my crossover values are actually what shows on the diagram) looking at c9 and c10 = 20uf. and c11 and c12 = 23uf. would you use an Audyn 22uf for both of those or would you use a 22uf for c11 and c12... and maybe an Audyn 15uf plus a 4.7uf for c9 and c10?

I'd probably buy three 20uF caps, and add a 3 and a 5uF where needed. I'd still plan on bypass caps for the Emits. That helps create smoother sound.

I also saw bradmich installed a Jantzen 6540 13mH 12awg c coil inductor in his crossovers. his theory is sound to me that it will make a difference compared to the factory 20awg inductor. but at 115$ a piece and two are needed for the pair.. that's getting pricey! do you think sonically that's worth it to spend for the low frequencies?

I've never changed out inductors, so I'm not sure? Some swear by changing coils, but you need to match inductance and resistance, when matching new inductors. If not, you can affect driver balance, and cause subtle response variations.
 
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