Brad1234

Thanks Doug, ur right. I forgot about the inductors and how they are matched with the cap values. I will keep the original cap values for my recap.

I have 4 OLA's I am getting ready to recap and found out they changed the crossover between my 2 models and cant figure out why? Older Advents have 2 16uF caps, while the 1975 or so later ones have a 16uF and an 8uF? I recapped a pair previously with the double 16uF caps and they sound amazing! Is there any reason to not recap the later model with dual 16uF's? Everything else is the same in the xover, and it sounds amazing that way. Any advice? On a related note, should I stuff the newer advent that had foam with fiberglass insulation? I have a bunch of it sitting around. I posted this on FB Advent group as well, sorry for double post.

I think also if you use too fine of a brush, the sealant will more quickly "seal up" the spaces between bristles and not apply as evenly the wet sealant. The coarse bristles of the supplied brush allow you to quickly gather wet sealant into the brush and drain it out quicker as u brush the speaker surround. Move quickly and use even back and forth strokes. It helps to put a piece of tape to mark ur starting point and do sections between screw holes between brush dips. It is hard to see where u have applied and not applied, and u dont want to use too much. It dries in brush fast so have all ur drivers ready to go before starting.

Sure, no problem! Those wires are super tricky, the heat from the solder gun burns thru them easily.

Congrats on quitting cigarettes! That is hard to do, keep up the good work!

Just put some solder on the tip of the gun and hold wire together and touch solder gun to it briefly and see if it sticks.

Nice, interesting combo of KLH and Advent. Wonder how it sounds? Also, that tweeter could be repaired with a a little solder on the wire. I have saved a number of tweeters by carefully soldering that hair-thin wire back together. Did u also recap the 2 caps on the tweeter switch by the terminal connections?

Thanks Jake. It's not that bad if you have a solid plan for the steps. I assume u have the removable woofers? First u remove the woofer and stuffing, document wiring (w photos), undo twisty ties for tweeter, 8uf cap and inductor, get a screwdriver and hammer and chisel out the back terminal plate (careful not to dent it) until it pops out on back, then pry it out and chisel off all the epoxy around resistors and caps. Once u have the plate off its easy to solder on new caps and resistors. A lot of people dont replace the resistors since they dont usually go bad, but they are very cheap so I usually do. I used the black "caulk n seal" rope caulk (from parts express) for woofer sealing on the back plate with screws instead of nails to secure it airtight, and used the rope caulk on the woofer and tweeter. Then dope ur woofer surrounds with vintage AR surround sealant if needed. Then ur speakers are as good as new! If ur gonna refinish the cabinets then its best to do that while the drivers are out too to keep dust away from drivers. This is probably too much info but I like to help other vintage speaker enthusiasts as much as I can, and this stuff is a fun hobby of mine!

JKent, I used a quick pour, probably about 2 shot glasses worth (about 60ml I estimate) in half a sink basin filled with cool water. Then used a rag to wipe it into the area of the grill that had the staining and scrubbed a little, then wiped around the area some to blend it a little. It looked horrible when wet after wiping, but dried to match rest of grill to my surprise. I dried it indoors, not out in the heat, to give bleach time to work. Good luck if you try it out!

Got the 2 new caps in for the switch plate and all sealed back up. Wow, what a difference in sound quality with replacing those 2 caps hidden in the epoxy! These speakers sound incredible, the vocals and mids are so clear, truly blown away and so happy I restored them. They sound better than the earlier epoxied woofers Model 6's I also have. The grills appear like they may be original and have held up very well. They had light staining around the woofer cutout u can see in the earlier pic. I took a gamble and tried wiping that area with a cloth wet with bleach water and let it air dry. Much to my surprise the staining has disappeared from the light coat of bleach water! See new pics of grills.

I got the epoxied switch plate out with a screwdriver and hammer, it popped off pretty easy working from inside of the speaker. Found the tiny cap to replace. Attached some pics. Im going to replace resistors too, i know I dont have to, but they are so cheap. I was thinking of just using the black seal-n-caulk rope stuff around the edge of back speaker hole before screwing down the plate to get it air tight. It works for the drivers so should work on back plate with using screws in place of nails. What do yall think?

Thanks Roy and Kent, I should have done my homework on this forum's past posts! Ah shucks, I already sealed the speakers back up. Looks like I will have to open them back up again and break up that epoxy. I forgot the caps wouldn't register with the resistors connected. I am a little disappointed with the "half-way restored" sound from them so I need to get those 2 epoxied-in caps replaced. Thanks so much for the help!

Hi Roy, there is an 8uF cap for the tweeter, but the wiring schematic I have for my other sixes has 2 2uF caps in addition to modify signal to tweeter with switch. I tested the leads and no capacitance was measured at any switch position, making me think there r just resistors on the switch? I attached the photo of the diagram I got online for the 6.

Correction on this post, looks like there are no caps in the epoxied speaker terminal cover, I measured it and there is no capacitance, just resistors, 3, 6 and 14 ohm. I had the wrong KLH Model 6 wiring schematic.

I am working on another KLH Model 6 restoration (stamped 1967 for the year on drivers) that I got on ebay for relatively cheap. This time I'm working on the model with the removable woofers. These speakers showed up in remarkably good condition, even the original grills are still in good shape! I am refinishing the cabinets and replaced the 8uF tweeter caps, the other 2 (2uF) caps are buried in epoxy with the switch on the back of the cabinet, so not planning to change them. Anyone have experience with changing those caps buried in the epoxy? The coolest thing I found about these speakers is one of the previous owners taped the original owners manual on the back and I was able to remove it and fold it open to reveal the original manual still in good condition, pretty cool! I got the woofers doped and sealed well, finished one speaker and working on second tomorrow. I have attached photos for your entertainment.

Hi Roy, I ordered an assortment of resistors with recap order I was doing for some other speakers to experiment with the mids and their perfect crossover point with tweeter on my 5's. I think I found it at 2.28 ohm resistors on the mids. I tried 1.5, 2, 2.5, and 3 and just wasnt getting the balance I hoped for. I could hear it was between 2 and 2.5, hooked up a 0.27 resistor and wallah! Perfect sync with woofer and tweeter w switches in "normal" position. Would have been a lot easier to just put an lpad on the mids maybe? But finally I can hear the full potential of these speakers, and have the upper and lower treble available on mid switches for fine tuning. It is crazy the tweeter is the only thing altered with the mid switch, but i tested it with mids disconnected and could hear tweeter changing with moving mid switch! But also, its weird the tweeter gets louder when disconnecting the mids? Its like the mids and tweeters are intricately wired together in crossover? These speakers are so complicated, but so wonderful when you figure them out and restore them. The sound quality is so good now with the mids balanced. See pics of my resistor dangling experiment.

I did check the capacitance of all of the new caps to make sure they were in range before installing them. They all checked out fine, in fact, I have yet to receive any caps that were not in range for the 10 sets of crossover rebuilds I have done, but still like to check them just to be sure. I know what you mean about looking for another speaker rebuild project, these KLH's were so much fun I found another set of model 6's on ebay untested for around $200, I cant wait to compare them to the 5's after rebuilding them. They are a lot simpler speakers than the 5's, should be fun, just hope they actually work!

I think the ESR maybe was it. I dont have a way to measure it as an amateur speaker rebuilder. But, the beauty of the KLH 5's is that u can hang the positive mid lead out on the baffle and test hooking up mutliple .33 ohm resistors until you get the right sound balance. It's crazy how even unhooked from the mids the speakers sound so great, guess that makes the 5 a 6 when it has no mids? I kept trying more .33 resistors in series until the mids were balanced right. The 1.5 ohm range was when it sounded best to my ears, with 3-way switches set to normal.

I have not noticed any response in the woofers pre and post xover rebuild. The woofers kick out amazingly deep bass and have been well doped to seal the surrounds and installed with the sealant rope caulk. The mid sound is coming out of the double mids and I have lowered it with a 1.5 ohm resistor. They sound amazing now! It was a slight tweak the leveling switches were not capable of. Lessons learned!

Hi Roy, thank you so much for replying to my post!! I very carefully checked the crossover wiring and only replaced like for like step by step in my rebuild. I have a ton of experience with electronics and feel confident these KLH 5 crossovers, though some of the most complicated I have encountered, are rebuilt to spec. I did use the mid-quality foil caps (Audyn Q4) so maybe they brightened up the mids a lot? But I think I fixed it, I trouble shot various ohm resistors on the mid positive lead and got the sound perfectly equalized, and it is a night and day difference! I landed on about 1.5-1.6 ohm resistor on the mids to get the sound perfect. I had a 1, 0.27 and 0.33 ohm resistor hooked up in series for best sound quality, ordered a 1.5 ohm single resistor to put in mid enclosure next week to finally finish rebuild. It makes sense what u said about the mid and tweeter switches not affecting the mids, I really struggled with that trying to adjust the sound. Please let me know your thoughts on my troubleshooting and solution.

Ok, back to my previous question on the midrange output on the 5's. I got the crossover issue fixed and mids sound great, but they are just too loud with the new foil caps and I have to turn my mid setting almost all the way down on my stereo for them to sound right. The 3 way switch on crossover just doest have enough db reduction capacity to equalize out the drivers. I was thinking if an Lpad or additional resistor in line with the mids could solve this problem? I know if I had just gone with the basic caps this may not have been an issue. Anyone have any ideas/suggestions for reducing the mid output further on the 5's when the new caps are just too loud?

Update to my above post, I fixed the midrange problem with my 5's! I isolated it to one of the speakers and spent a few hours opening it all up again and checking every connection on the xover. Nothing was wired wrong but there were some connections on the 2 level switches that looked like they might have been touching. I cleaned up the ground rivets, and put a little solder on them just in case that was the problem. I made sure all wires were clear of the chassis ground plate and put it all back together, fired it up and the mids sound normal and the tweeter is louder and clearer too. Now I can see why everyone raves about these speakers, they sound amazing!

I finished up my Model 5 restoration of the grills and they came out nice. I used linen fabric from Joann Fabrics, it was only around $10 and looks great! I have a question on the recap job for the experts, I used Audyn PP Q4 Intertechnick capacitors and double and triple checked the values and connections when assembling it, but after playing them for a while the mids just seem so much louder and overpowering the sound stage, even turned down to low setting. Is this just how 5's sound or is there possibly some explanation in the cap difference over the original caps, or resistors I could add to tone them down some? I am playing them on a Marantz 2270 and have used other speakers in their place with no mid problem. Any advice will be so appreciated!

On a related note, and I know there probably is no real answer to this, but is/are there recommended capacitor brand(s) for recapping "vintage" speakers? I have used Auden and Jantzen Polypropylene caps from Parts express in several recaps and have been pretty happy with them. I tried a Auden plus Intertechnik foil 0.33 uF foil bypass cap that cost like $15, and was very disappointed with the sound in my Dynaco A25's, tweeter was waaaayy to harsh. I removed and went with Auden PP .33 cap and got much better sound quality. I think with the vintage speakers, the foil caps are overkill and makes them sound to harsh? Am I right about this assumption?

I grew up listening to my parents square magnet NLA's since the early 80's, and conned them into trading them to me for some pawn shop Technics speakers in high school, so I know the sound of the Advent square magnet well. When I got another set of NLA's with the new woofer round magnet replacement, I could immediately tell the difference. And I had my childhood NLA's still to compare them to, it was easily discernible. There is no question in my mind, the bass is deeper and the mid is clearer on the square magnet original woofers.