STL Posted November 18, 2004 Share Posted November 18, 2004 I know levir has done it, but I was curious to know if anyone else has done one. I myself am getting close to buying the parts to upgrade the networks in my KG5.5s (and my custom center that's based on a KG5.5), but I thought I'd make one last sweep to look for experiences others have had doing this filter upgrade. Quote Link to comment Share on other sites More sharing options...
Deang Posted November 18, 2004 Share Posted November 18, 2004 Hi Brett, I'm so sorry about not getting to the email. I've done 'em, no schematic though. Remember, your working with PCB's, so your geography is limited. By the time you get the caps on, you have no room to play with inductors. Now, you can get imaginitive, and mount a nice Erse Super Q steel laminate on a separate board. There is already an air core in the HF section. I would just leave the electrolytic in the LF in the circuit -- it's good enough for that. Besides, there just isn't room to put a Solen on there. Just replace the 8uF and 2.5uF caps on each board with some Auricaps or Kimber Kaps, and the resistor with a 2 ohm Mills. If you aren't going to dump gobs of power into those things, you can also yank the polyswitch and replace it with a 1 ohm Mills. That one is your call. I did it for a customer and he said it worked out fine. If you send me digital pics of the bottom and top of one of the boards, I can draw a schematic for you -- and then you could build point-to-point boards with some plywood. Quote Link to comment Share on other sites More sharing options...
Deang Posted November 18, 2004 Share Posted November 18, 2004 The RC-7 -- the mod from Hell. Everything on the bottom of the top board was put there by me -- all of it moved from the top to accomodate the large values. I actually had no choice but to use some Solens, because the Auricaps in those values were the size of aircraft hangers. Now, suppose I had wanted to use some different inductors? The point is that you can take some license if you think it out and take your time. Quote Link to comment Share on other sites More sharing options...
STL Posted November 19, 2004 Author Share Posted November 19, 2004 Thanks for the info Dean. You must have misunderstood me as I said I already have the schematic. I am just looking for personal experiences so I know what works and what doesn't. I guess I need to take out one of the boards to start measuring and mapping things out. I was just going to order the parts and make them work -- but maybe that isn't the best idea. I must admit that I am back and forth on what parts to use. One minute I think I'm using these Dayton combo: 2.0uF Metallized Poly Cap + 0.47uF Film & Foil Poly Cap and 7.5uF Metallized Poly Cap + 0.47uF Film & Foil Poly Cap -- and the next minute I'm leaning towards the much more expensive Kimber Kaps (in 2.5uF and 8.0 uF). I'm also not sure what to do with the coils. You mention using two 20ga. air coils in a previous post, but with one of them out of stock (at Parts Express) until next year I'm thinking about going with 18ga. models instead (knowing the DCR will be off). Then again, maybe I should check and see what Madisound has. Oh on the Erse suggestion...since the smallest coil they make is 1.5mH, I would have to unwind several winding to get it down to 1.0mH, right? Also, they don't have the DCR specs listed so I guess I'd be running the risk of dropping the DCR too low with them too, right? Thanks again... Quote Link to comment Share on other sites More sharing options...
STL Posted November 19, 2004 Author Share Posted November 19, 2004 Oh yea, I forgot to ask... You said not to bother replacing the LF cap with a solen because there wasn't room -- but should I go ahead and replace it with another 24uF non-polarized cap (or a pair of 12uF ones)? Either way I was planning on adding a (Dayton) bypass cap. Speaking of bypass caps, why should I not be considering just adding quality (Kimber or Theta) bypass caps on all the existing HF caps instead of replacing them? I figure there must be a good reason... Quote Link to comment Share on other sites More sharing options...
Deang Posted November 19, 2004 Share Posted November 19, 2004 Bypassing with the Mylars comes under "the least of what you can do is" -- if you are going to do this right, get rid of them. Pairing up a 2.0uF with a .47uF film and foil is closer to paralleling than it is to "bypassing". To "bypass", you need the bypass cap to be at least 10x the value of the other cap, preferably more. If I were doing it, I would just use a 2.5uF with a .01uF. Now, this is just from what I've read, and I can't give the technical reasons for it. To muddy the waters even more, you could even build a film bank using just the .47uF's -- five of them in parallel. You might find the tweeter a bit hot -- but it will be as clean as it can get. Tempting, considering the price on those .47's. With all that out of the way, I say keep it simple and just use the Kimbers. Like the Auricap (and probably rolled up in the same factory -- along with the Hovlands) -- they are very clean and transparent without sounding sizzly. I especially like the lead terminations on these caps better than the Dayton's. Looking through my scribble marks on the KG 5.5, I think the DCR on the Erse inductors for the LF is too low -- about .17 (also too big for the PCB). I think the iron core on the KG 5.5 is .65mH with a DCR of .3. Here is a good time to move to an air core -- simply because there is a good match. A Janzten 15 gauge of .68mH with a DCR of .24 will work well here. http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=255-414&DID=7 When you replace the electrolytic, move it to the bottom of the board with the resistor -- and you might have room for this thing on top -- but you will have to drill a hole in the PCB and strap it. Differing opinions on the importance of DCR on the HF inductor. I still lean to keeping it as close as possible, and if you can't find a match -- I say leave well enough alone. I don't remember the inductance value, and I didn't write it down -- but you have the schematic. What is is the inducatance and DCR of that thing? Quote Link to comment Share on other sites More sharing options...
STL Posted November 19, 2004 Author Share Posted November 19, 2004 Okay the mylars are gone...it was just a fleeting thought. The use of combo Dayton caps was really more to get the correct value since they don't offer a 2.5uF or a 8.0uF. I guess using the film and foil .47uF caps would be pointless though. If I want to go with Dayton (because of their price) I could get several 2.7uF and 8.2uF caps and use the ones that spec out low. In an earlier thread, you mentioned using 20 gauge coils because getting too low a DCR can be too much of a good thing. That's why I didn't go directly to the larger gauge models. Also, in your last post you talk about the 0.6mH as if it's the LF coil, but that is the HF coil. See the attached schematic. I just measured the DCR on those coils (while leaving them in the circuit) and both read roughly 0.5 ohms. The 0.6mH HF coil read 0.5 ohms (DC) but occasionally popped up to 0.6 ohms. The 1.0mH LF coil read 0.5 ohms but sometimes dropped down to 0.4 ohms. That being said, I think a few tenths of resistance might be my leads (since that's what they measured when shorted). Until now, I never realized how crummy my meter is at measuring low resistance; tenths was as low as it would read. kg5.5_network.pdf Quote Link to comment Share on other sites More sharing options...
STL Posted November 21, 2004 Author Share Posted November 21, 2004 I think I have finally decided on my filter upgrade. I am going to use Dayton caps with Theta bypass caps for the HF caps. For the LF cap, I'll just bypass the stock electrolytic with a Dayton film & foil bypass cap. I'm going with air cores for both coils. For the LF one I'll use a 15 gauge Jantzen, and for the HF one I'll use a 18 gauge Jantzen. I'll also replace the resistor will a Mills one. Even though I don't run a lot of power to them, I plan to just leave the circuit breaker just to be safe. All this should fit on the OEM board. See the attached image. On this side, I'll place all the caps (except maybe the bypass cap for the LF section). I also might move the resistor to this side. Quote Link to comment Share on other sites More sharing options...
STL Posted November 21, 2004 Author Share Posted November 21, 2004 See the attached image. On this other side, I'll place both the coils and probably the bypass cap for the LF section. Any opinions or suggestion are welcome... Quote Link to comment Share on other sites More sharing options...
Deang Posted November 23, 2004 Share Posted November 23, 2004 You won't get the coils on the bottom and be able to get the board back on the bottom of terminal cup -- there won't be enough clearance. You can use nylon spacers and longer #6 screws -- but be careful when you screw them back in, or you'll split the posts. You can get the spacers from http://www.mouser.com I would put the Mills resistor, and two new 12uF electrolyics with the bypass cap on the bottom. Use epoxy for mounting the latter to the bottom. http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=027-342&DID=7 Scrape all of the old adhesive off, lightly scuff the top of the board with 220, and then clean with denatured alcohol. Get everything OFF. Same with the bottom: Remove ALL of the old solder with a braid, and clean off the flux with denatured alcohol, Q-tips, and a cotton cloth. I would stack the 2.5uF on top of the 8uF. Lightly scuff the exterior of the caps where you are putting the adhesive. When you place the 2uF on top, don't push so hard that you squish all of the adhesive out -- just lightly press down. Once the adhesive sets, it's almost impossible to pull the caps apart (or off the board). I prefer the hot melt from Partsexpress. It's good stuff. At this point you should have plenty of room for the inductors. Sit the 15 gauge upright -- a good pool of hot melt, and a tie strap. After you get the tie strap on -- more hot melt through the middle until it just starts to hit the board. Sit the HF inductor flat, and as far away from the other one as possible -- mutual inductance sucks. Again, a good deal of hot melt -- and just sit the inductor in it (lightly press if you feel you must). One more important thing. It won't take you long to find out that the leads from the Auricaps will not go through the holes in the PCB. So, break out the drill and a 1/16" drill bit. Get the drill going at the high speed before you hit the hole -- or the foil from around the hole will lift up from the board. If the foil lifts -- drill a new hole next to the original, and then scrape the material around the new hole down to the copper foil with an exacto knife -- if you don't, the solder won't take. Don't be surprised if a lead comes off the board where the autotransformer is attached. You'll understand what I mean once you get going. Quote Link to comment Share on other sites More sharing options...
STL Posted November 24, 2004 Author Share Posted November 24, 2004 Thanks for the info Dean! I'll be sure to post some pics once I get them done (but sadly that won't be anytime real soon). Quote Link to comment Share on other sites More sharing options...
pocketchange Posted April 30, 2005 Share Posted April 30, 2005 ---------------- On 11/24/2004 11:32:07 AM STL wrote: Thanks for the info Dean! I'll be sure to post some pics once I get them done (but sadly that won't be anytime real soon). ---------------- Where are the follow up views of the modded XOs? FOOD FOR THOUGHT (maybe): What about splitting the 10s and having a 3way system? Add an LPad to the horn/tweeter. If I could get some driver info on the 5.5s, I would like to give this a shot. pc Quote Link to comment Share on other sites More sharing options...
popbumper Posted April 30, 2005 Share Posted April 30, 2005 Of course, rather than kludging existing crossovers with hot melt, and suffering over parts placement issues, scraping off soldermask, etc., one could design some PCB's, build brand new units, and improve the quality of the whole network across the board, while maintaining the stock network. Nah, that would be a dumb idea...;>). Chris Quote Link to comment Share on other sites More sharing options...
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