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JBL l166 Horizon rebuild help

M50'sMike

M50'sMike

Member
Hello all, I posted this on audio heritage earlier and I was wondering what your guy's thoughts are. I am here to just get an idea on what to do to bring back life to my l166 Horizons left mid-range. the left channel does not work I've tried cleaning the l-pad I even took the cap off (which hurt me inside) I'm about to put the right channel mid-range into the left to see if I just bought a bad midrange off eBay (don't have a volt meter). I got this pair of l166's as a gift, gifted to me by my future father-in-law for Christmas. The left mid-range stopped working some time ago I'm not entirely sure if it was even working when I got them, my memory is failing me but his son had replaced the woofers with JBL loud car woofers so I bought some 128h Woofers off of eBay and put those in. It's a night-and-day difference, but Im curious as to whether or not the 122a wolfers are better.(or how they differ from the 122a's) I'm not necessarily looking for an all-original build but if I could use all original JBL parts from back in that time period to make the best floor standing speakers to my ears, that would be wonderful. Any response is greatly appreciated. I also am wondering if the le5 - 5 out of the jubals would be an upgrade in the sense of sound for the mid-range. Because I saw some spec sheets of all the le5's and the charts that I don't know how to read showed big differences I between the two. Sorry if I am bringing pain to the Grandmasters who like them all original. I'm just trying to figure out what I like. Thanks again everyone
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Oh and I'm pretty sure I figured out why the mid doesn't work. It needs a new resistor, can somebody help me figure out which one it is? I feel silly cause I can't read the sheet. I'll post pictures. There are two stacked on top of each other.
,Mike
 
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Where do you live, Mike??
maybe if you post your town someone local could give you a hand - or have some ideas ...

Sounds like you are not particularly technical about speakers (no offense, most folks aren't - I have done pro audio and video engineering for 20+ years, among other things).
Generally, you are better if you can leave them mostly stock, they had a good reputation when they were made and haphazardly swapping drivers around will probably not result in anything close to quality sound ...
 
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IMG_20170505_092443898.jpg 7333.jpeg

The white resistor is the one with the crack, it's on the opposite end. I just can't figure out it's value because I don't know how to read the sheet properly.
 
M50'sMike said:
I live in Olympia in Washington state :)
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Okay, wrong coast for me - I am outside Wash DC - but maybe someone out west can help you sort them out.
The crossover Schematic is here on the Harman site -

http://manuals.harman.com/JBL/HOM/Technical Sheet/L166 ts.pdf

Based on that, the big cast resister is either
4 ohms at 10watts, or the
20 ohms at 10 watts - I can't tell which is which from your picture -
but both are on the midrange part of the circuit, and they should be MARKED ...

Screen Shot 2017-05-06 at 6.55.13 PM.png
 
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If your mid isnt working, its most likely either the Lpad or the 8uF cap. Assuming the actual driver is working anyway. First thing to try, after confirming that the driver is good, is just cleaning the Lpad.

If I were you I would stick with parts original to the L166. If you start swapping parts out you're going to lower the value of your speakers. An L166 IS the parts used by JBL. Not just the enclosure.
 
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L200B said:
If your mid isnt working, its most likely either the Lpad or the 8uF cap. Assuming the actual driver is working anyway. First thing to try, after confirming that the driver is good, is just cleaning the Lpad.

If I were you I would stick with parts original to the L166. If you start swapping parts out you're going to lower the value of your speakers. An L166 IS the parts used by JBL. Not just the enclosure.
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I've taken the cap off of the l-pad and clean it out very thoroughly for about a solid 45 minutes with deoxit and I've confirmed that the driver is working by putting my working midrange that works in the right channel into the Left Channel and it did not work. But I have a cracked resistor that I'm questioning because that really seems to be the only thing it could be at this point. Unless there are other things that could be wrong that I don't know about, I'm having trouble reading the schematic that tells me the values of the resistor because I can't seem to figure it out.
 
Check the resistor with a multimeter. Necessary tool if you want to work on stuff like this.
 
Agree with L200B - don't just start swapping piece indiscriminately and hope you have some success.
Get some better tools to test things and let us help remotely, or get a local friend with tools and skills ...

I'd agree you probably have a physically cracked resistor -
You can buy the two values I listed from parts express for under $20, but you will need a soldering iron and solder
to sub a new one for the broken one ...
 
Hello everybody, apologies for no update ever. The mid range in my l166 works, after reconnecting everything it just, worked. My guess is oxidation. But they have been going strong since. But I feel that it's past time to re cap these horizons. But are curious as to what the values of said caps might be. (And do not really know how to read the schematics yet) I would like to avoid opening up the speakers until I have to do the recapping. Also wondering, any recommended brands of caps? Thanks.
 
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What symptom are you hearing that makes you feel that the original film caps are needing replacement? Are you looking for a different sound?
 
No symptoms. :) Just been looking around the forums and people have been recommending if the gear is 30 years or older it'd be worth doing regardless of if they're going out or not. I do believe I'm happy with their sound they're putting out, they are wonderful speakers, just want to make sure I'm getting the intended and best sound from them. Also have seen people saying they're meant to be oriented on their sides like a "horizon" but I've had no way of confirming whether or not that is the case, it doesn't say it nor show it anywhere in the manual. And I haven't tried it yet because I have a piece of live edge wood bridging the two of them to hold my TV above them.
 
Orient them as you like them. I was always a vertical oritientation guy, but in a true bookshelf application, they would need to be on their sides.

Regarding capacitor replacement? The internet has its lore, but if the film caps in them sound good to you, they quite likely still are as film caps age pretty well. The cones have changed, cabinets might have changed, magnets have changed, the least change is likely the caps over the years. Again though, if you want to replace them they are your speakers and unless you're concerned about the value of them, change away.
 
Not concerned about the value at all, haha. My only worry was the caps may have degraded over time. Still love the sound. Still on the look out for 122a woofers though, curious how the sound of them compares to the 128h's I put in them. The manual says to replace the 122's with the 28's if the 22's aren't available but I imagine they'd differ at least a little.
 
And ay I note, I am here for opinions on the path I should take for bringing these Horizons to their full glory. Any opinion is more than welcome. I appreciate the input regardless.
 
I’m not looking at the JBL spec sheet, but it will specify if the recommended replacement is an exact match or there is a sonic change. If a sonic change, and replaced in pairs as recommended, it is likely still an L166 to the ear.

If you’re looking for sonic bliss and to enjoy the music from an excellent set of early ‘70s speakers that also look excellent, sit back and enjoy.

If you’re looking for the most accurate, flat, and best imaging speakers for your money regardless of style, sell them and buy a new pair of 590s.

I have (and have had) high-end modern speakers, and for the past few years have been enjoying high-end vintage speakers, and I can tell you that from a standpoint of pure enjoyment of music I’ve stopped listening to the new and spec-perfect, am not looking forward to garage-workshop weather where I’ll take the Altecs out of service to refinish the cabinets (but will likely resort to the Summits during the restoration).
 
M50'sMike said:
Hello everybody, apologies for no update ever. The mid range in my l166 works, after reconnecting everything it just, worked. My guess is oxidation. But they have been going strong since. But I feel that it's past time to re cap these horizons. But are curious as to what the values of said caps might be. (And do not really know how to read the schematics yet) I would like to avoid opening up the speakers until I have to do the recapping. Also wondering, any recommended brands of caps? Thanks.
Click to expand...
Hello. I have recently refurbished a pair of L166's and I'm loving them. I ultimately replaced my entire crossover network including the board it is built on. I used the same values as the original crossover network. It did get switched up somewhat though in that I used air core inductors instead of iron core inductors primarily because I could not find any with the proper matching values. I used DaytonAudio audio grade caps. There are 3 4.0 caps on each board, with two of the three wired to make one 8.0 cap. Check the pics out.
Before changing the crossovers out I listened to it for a while and they sound nice with the og x-overs, but I kept reading that caps that old most likely need replacing sooner or later, so I did it. I took the ogs out and put them in a plastic bag inside a box and put them on the shelf and built the new ones. Not sure if it was real or imagined, but it did seem that the speakers sounded better, they seemed crisper and cleaner. I have had them in for a while now and they are getting fairly well broken in and the bass transients do seem very clean, I don't know if I even lost enough transient response to notice a difference from the ogs to the new x-overs.
I did it this way so if there was a detrimental effect or if I did ever resale and the person buying wanted the og x-overs, I would have them too replace the new ones by just dropping them back in.
IMG_20210326_162354575[1].jpg IMG_20210326_162305672[1].jpg
 
SaturationPt said:
What symptom are you hearing that makes you feel that the original film caps are needing replacement? Are you looking for a different sound?
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Hey, I don't mean to hijack this thread, I'm trying to build up a pair of L166's. I stumbled across a pair of empty cabs in great condition. Is there a shop that will build a pair of cross over boards if I can't find any original? I know it's not the space shuttle but I try to limit my electronic tinkering. In the stupidly obscure question department does anyone know who manufactured the egg crate grills for JBL? I've had a little luck over the years getting old race car parts manufactured and you never know til you ask.
 
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