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Chours II & Forte II Crossover and resto & soem JBL Century stuff too


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I am finally completing my Chorus II and Forte II crossovers.  I will post when I do the rebuilds, hopefully this weekend.  I received these badges today from the guy in Russia.   They are very nice. 

 

I am looking for grill cloth, likely the Silver Luster Grill Cloth if Duracrest has it in stock.  Does he have it in stock now? 

Can anyone point me in the direction for a set of plans to build the grill frames?  I want to build a second set from scratch.  I can do it but why re-invent the wheel. 

 

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I need to recap my JBL 4311s... I thought about one of the aftermarket designs, but they are really too expensive.

 

Also have some Sansui SP2000s that I'm pretty positive need new caps, or they just sound bad. Won't know until I get one done to compare.

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16 minutes ago, Marvel said:

I need to recap my JBL 4311s... I thought about one of the aftermarket designs, but they are really too expensive.

 

Also have some Sansui SP2000s that I'm pretty positive need new caps, or they just sound bad. Won't know until I get one done to compare.

I think that I paid $8 shipped for the tweeter foams (I know that you need these).

 

I would not change the JBL crossovers to a different design.  I read that they do not sound any better and in any event, I want these to sound just like they did when new, rolled off top and a hump in the bass and all.  That is what they are and how I want them to sound. 

 

I kept hearing that the caps are still good in the JBLs because they are 'good for 50 years.'  Well I did the math and realized that they are about due.  Actually, the L pads are worn out so I figured it was time.  This was actually quite a bit of work, especially figuring out a layout that fit on the dimension of the stock boards with the oversized L Pads and barrier strips.  The depth of the L Pad stems was also an issue, bet easily solved by going to 1/2" wood.  Luckily I had a bunch of leftover 1/2" baltic birch.  If you just need caps, it should be very easy on the 4311.  The L100 Century requires that you remove the foilcal.  I am going to fix that problem. 

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You have to remove the foilcal on the 4311s, too.

 

I may have a broken lead on one of the tweeters, and the replacements aren't near the same. If I can fet by by simply replacing the foam rings it will be a good thing.

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16 hours ago, Marvel said:

You have to remove the foilcal on the 4311s, too.

 

I may have a broken lead on one of the tweeters, and the replacements aren't near the same. If I can fet by by simply replacing the foam rings it will be a good thing.

A delicate job, but you can get some stranded wire, remove a wire of about the same size and fix the lead if there is room to work.  Just a delicate dab of solder. 

 

I also put scotch tape below and above the leads before putting the new foams on.  If I ever need to remove the foams, they will pull the scotch tape off instead of the leads. 

 

Boy, no love for my crossovers on this forum.

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Forte II crossovers are done.  I was able to mount the 1.5 uF cap on the board, the rest had to be moved. 

 

All ends are soldered, crimps are crimped, soldered and heat shrinked.  The boards are meant to go in the bottom of the speaker on 1/2 spacers that I ripped from the Baltic birch scraps.  I used open ended lugs on these connections to make it easier to install when reaching into the speaker.  I made the boards relatively small to allow plenty of space for bracing if I go that route.  

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  • 2 weeks later...
18 minutes ago, EpicKlipschFan said:

they look great.  maybe i missed the details but what caps did you use & how do they sound?  & what is the reason or benefit of moving everything to a separate board? 

Thanks.

 

Jantzen Z Caps from Partsexpress.  I got them because they are reasonably priced, easy to get as I already needed other stuff from Partsexpress and they are rated high on Humble homeade  hifi.

 

The new caps are quite a bit larger than the original caps, so they do not fit on the boards.  I also needed to double up most of them.  I could have made it work with zip tied and hot glue, but it is much neater and more organized to do them this way.

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8 hours ago, EpicKlipschFan said:

& what is the reason or benefit of moving everything to a separate board? 

 

7 hours ago, tigerwoodKhorns said:

... The new caps are quite a bit larger than the original caps, so they do not fit on the boards.

 

Similar thing when I re-capped some Heresy IIs last year and also needed to mount them on a separate board, because if the larger caps were attached to the speaker terminal cup, OEM style, it would not fit back in through the hole in the cabinet.

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2 hours ago, Marvel said:

Chris, they all look great. That is far more time consuming that many realize.

 

27 minutes ago, Crankysoldermeister said:

Oh yes, and the better you want it to look, the longer it takes.

 

It’s always interesting to see how others decide to do things. 

 

Thank to both of you.  Yes, this took so much time to do.  I didn't count the hours, but days worth.  Now that I have it designed, it would take less time, but still a significant amount of time to get everything laid out and put together. 

 

The crossover builders on these forums earn their money, this is a lot of work that most do not realize. 

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