• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

JBL 4311's = system complete... for now.

I recapped the pair 4311s I just refinished with Daytons and and decided to add 0.01uF by-pass caps like JBL used in later speaker models. They sound very nice.
 
Yup, Daytons are improved with bypass.

My favorite Theta 0.01s have gotten a bit pricey, alas. :pity:
 
Zilch said:
Yup, Daytons are improved with bypass.

My favorite Theta 0.01s have gotten a bit pricey, alas. :pity:
Click to expand...
I used 0.01uF 400v Sprague Vitamin Qs so that it was something different than just two different kinds of polypropylene caps. The poly film (Daytons) and glass sealed paper-oil (Vitamin Qs) combo seem to compliment each other and to me, sound nicer than the Dayton/Thetas. :music: Qty 20 for $24 was a bargain compared to Thetas...
 
Well, COOL! I'll order up some VQs here and give 'em a try. Thanks for the suggestion.... :thmbsp:
 
xoaphexox said:
In the last week I picked up two pairs of 4311's. One has the 'A' designation on the rear label while the other does not. All the drivers appear identical, and the only physical difference I can tell other than the label itself is that the L-Pads on one pair have a detented feel when turning them, and the other pair are completely smooth when turning them.

My question: is there a reason to recap these speakers beyond trying to change the sound from spec? As in, are the capacitors used in the original crossovers electrolytic and drying out as they age?

I am hesitant to pull off the metal plates to get to the x-overs because I do not want to accidentally damage these speakers. If the stock caps are not the kind that wear with age, I see no need to dig in and change them out.

However, one pair of these (the non-'A' pair) seem to have more midrange than the other pair at a flat EQ curve on both the amp and the speaker L-Pads themselves.

I am trying to get a feel for how deep into the restoration I should go.

I also have a darn tweeter nipple that needs sucked back out.
Click to expand...

Sorry for the (very) belated reply.

Before I rebuilt my crossovers, the speakers sounded ok sometimes, if you didn't fiddle with the L-pads. But when you started doing that, it was obvious that something was up. Since the L-pads needed to be replaced, and I had to take the crossovers out to get to them, it was only logical to replace the caps too. The paper-wax-sand (I don't really know the techno correct term for them) caps probably aren't exactly lifetimers. One set had actually melted the wax, and was leaking sand out. I don't know how indicative of this type of cap mine are, but seems to me that if 2 out of the 4 caps were crapped out, those aren't very good odds for the 8 (2 per speaker times 4 speakers) of yours.

I chose the caps I did based on wiser members' recommendations of different brands reproducing different sounds. While I don't know how it works, or even if they make a difference, I took their word that the Daytons were going to make my speakers do what JBL intended them to do.

Also, I think it would be remiss to count the sound that your speakers are producing with possibly degraded caps as 'original' considering that the original sound had caps that were within spec. Perhaps yours are still functional, but having anything that's 30 years old with no maintenance and thinking it's going to function at 100% is a bit of a stretch in my opinion. Then again, if you're happy with the way your speakers sound, and are afraid you're going to damage something, then use your speakers the way they are. I'm not there listening to them. I'm in my basement listening to my restored ones that are now fully functional.

If you feel like taking the task on, I hope my experience helps you. That's what these forums are about and are for, and that's why I posted this thread.
 
Based on your kind emails and input, I did my XO's this weekend with the "improved original" option.

In my case 3 of the 4 LPads were bad, and one of the 4 caps was shot.

The difference is startling. The clarity and depth compared to before is like new, considering I never heard them new, maybe better.

Tried two different amp combinations, Marantz 2275 and the GAS Son of Ampzilla. It was like somebody turned on mid to high end that was muted before.

Thanks for a great recommendation and parts listing. If you can recomboobalate all these posts into one logical post, I think it will help. I caught myself having to look at the photos to make sure I got the green/red wires to the right set of caps.

You rock (literally) dude.
 
I had the same result. I was like "HOLY COW SOMEONE TURNED ON THE SPEAKERS!"

I'm glad you got yours restored. I don't know if I said it anywhere, but I'm really glad I did mine, and I hope this thread helps save more and more sets.
 
I just finished the 'Improved Original' recap tonight. It was pretty straightforward. The only issue I had was the goop that keeps the old capacitors on the crossover panel. It was nearly impossible to get off.

Also, my capacitors were not labeled with their values at all, only serial number. Luckily the crossover schematic has the capacitor serial numbers on it as well.

Thank you very much for taking the time to post these pictures and description!!
 
This thought just crossed my mind - whats the deal with the sand filled caps? Can anyone explain the usefulness of these? In my ignorant mind it just seems like pointless extra space.
 
Use a hair dryer and putty knife. Heat the glue up for 30 to 45 seconds and
scrap. The stuff is messy so do not get it on anything else. Sand in the old
caps just buffer for space.
 
The sand is also a damper for vibration.

In any orientation, vibration will pack it tightly around the wound foil and reduce microphonic capacitance changes.

A vibration analysis expert over on LHF built his DIY crossover in a separate chamber and packed it with fine-grain sand to minimize triboelectric effects in all of the components.

It also works for eliminating resonances in horns.... :yes:
 
Reading this thread makes me want to perform this operation on mine. I've got a soldering iron but not much experience to speak of. The last time I had the iron in my hand I nearly melted the tuner string in half on one of my receivers. Makes me nervous just to look at it.
 
Thanks so much for this walkthough post! It is now over a week since recapping the 4311's and they have truely come alive!

What a great return-on-investment recapping these speakers was. I also recently put some metal film polyester 1uf 100V Vishay capacitors across all eight power supply capacitors in my Sansui G-8000 and they play very very well with it.

Cloud nine!
 
I just recapped one speaker from my other pair of 4311's tonight. This pair had all the same driver numbers (LE5-2 alnico mid, 2213 woofer, LE25 tweeter) but the caps were different (not values, just composition and label). These were labeled 'T.I. Mexico' and the values, 200V and were all wax on the inside instead of the sand like in my other pair. They also had physically larger Alps L-pads that say 50dB just like in the picture on page 1. My other pair had much smaller L-pads that were not labeled.

Is this the difference between 4311 and 4311A ?

At first listen after doing only one speaker, the pair I recapped a few weeks ago have a much more pronounced sound coming out of the tweeter. So much so, in fact, that I am debating taking it back apart and making sure I wired everything up correctly. It is really hard to mess up though with two bright orange wires going to the 3uF and two bright green going to the 8uF cap...

I used a frequency generator to make sure that sound was in fact coming out of all three speakers and compared this sound to a recapped 4311 side-by-side to make sure I was not losing my mind.

Tomorrow night I will do the other speaker and see if this treble weirdness persists.
 
An addendum to this thread:

I am working my way through rebuilding the xovers, I wanted to add pictures of what I found.

xover1.JPG


No name, no number, no label.

xover2.JPG


Interestingly, my caps are reversed from the ones in Brainwashed's original picture. Also of interest (probably only to me), the wiring on this xover exactly duplicates the color scheme called out on the 3112-C schematic, but the parts match the 3112/3112 A,B schematics.

According to this:

http://www.jblproservice.com/pdf/Systems Reference Charts/Studio Monitor Series.pdf

the network is a 3112B (this matches the drivers: 2213H, LE5-10, and a LE25-2)
 
hi, can i use this "kit upgrade" for L100A ? (woofer 123A-1 / Mid LE5-2 / Hi LE25)

a originals caps: 8uf and 3 uf. and if this pot can work in L100 ?

4 x L-PAD 15W MONO 3/8" SHAFT Part Number 260-248
http://www.parts-express.com//pe/showdetl.cfm?&Partnumber=260-248

4 x AUDIOCAP PPT THETA .010µF-600V FILM/FOIL CAPACITOR Part Number 027-700
2 x DAYTON PMPC-3.0 3.0µF-250V PRECISION AUDIO CAPACITOR Part Number 027-220
4 x DAYTON PMPC-4.0 4.0µF-250V PRECISION AUDIO CAPACITOR Part Number 027-226
 
The original L-pad is 10W, I believe.

There are limitations as to how large, physically, will fit in the original spacing....
 
You must log in or register to reply here.
Back
Top Bottom