JBL L36 Decades Reimagined

[MCM_Fan]

A couple months ago, I picked up a pair a pretty trashed L36 Decades. But, as they say in the home restoration business, they had good bones. They are my first pair of JBLs and I decided to make them the subject of my first speaker rebuild project. The original plan was an authentic restoration, with burnt orange grill cloth and golden oak finish on the veneer. However, those plans changed...

Here's what they looked like when I found them:

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_Before_1_zpsskor56wh.jpg

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_Before_2_zpsr6qv3d0j.jpg

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_Before_3_zpsvbqqce6t.jpg

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_Before_4_zpstrzsmyla.jpg

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_Before_5_zpsgdejha5x.jpg

[MCM_Fan]

And, here's what they look like now:

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_After_1_zps8ds8zbgh.jpg

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_After_2_zpsgky2fi5u.jpg

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_After_4_zpsy7lxnacw.jpg

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_L36_Decade_After_3_zpsf7owipm0.jpg

[MCM_Fan]

In addition to the externally visible improvements, I also rebuilt the crossovers and disassembled, cleaned and reassembled the L-pads:

Crossover Before:

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_Decade_Crossover_1_zpsmuhohdx6.jpg

Crossover After:

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_Decade_Crossover_4_zpsq0b8ojpv.jpg

Disassembled and Cleaned L-Pads:

http://i1204.photobucket.com/albums/bb414/kerrythalmann/JBL_Decade_Crossover_3_zpshfkqejwb.jpg

Note: after the photos were taken, I also added 0.01uF Vishay MKP1837 bypass caps across the 3uF Sonicap tweeter caps.

[MCM_Fan]

The inspiration for my change of direction were Jan's gorgeous, custom built, one-of-a-kind L300s shown here (http://www.audioheritage.org/vbulletin/showthread.php?22289-Grill-Cloth-Found&p=287364&viewfull=1#post287364).

You can read more details on my process here (http://audiokarma.org/forums/index.php?threads/trashed-jbl-l36-decade-restoration-i-need-your-help.710060/).

If there are any specific questions about this project, please post them here and I'll do my best to provide detailed answers.

I've been enjoying listening to them since last Sunday morning. They now have over 50 hours on them and sound great, every bit as good as they look (IMHO). It was a fun project and I am now an official member of the JBL community.

[gdmoore28]

I try not to say "wow" very often. Being from the south, more often our exclamations start with an "s." But your restoration deserves a "WOW!" You even made sure that the script on the pots are aligned. Small details like that just shout goodness. Great job, Bub!

GeeDeeEmm

[Mr. Widget]

Very nicely done... excellent work indeed.

If those were in my living room instead of the enormous beasts that dominate it, I would be out of the dog house and more respected by society at large.


Widget

[grumpy]

Out of the dog house, perhaps. ;)

[MCM_Fan]

I try not to say "wow" very often. Being from the south, more often our exclamations start with an "s." But your restoration deserves a "WOW!" You even made sure that the script on the pots are aligned. Small details like that just shout goodness. Great job, Bub!

GeeDeeEmm

Thanks for the "WOW!". It was a very fun, rewarding project.

And aligning the script on the pots serves a useful purpose. It insures they are both in the neutral position when the knobs are set at the straight up 12 o'clock position. That, and I tend to be a stickler for such details, even if no one but me will ever see them again.

[MCM_Fan]

Very nicely done... excellent work indeed.

If those were in my living room instead of the enormous beasts that dominate it, I would be out of the dog house and more respected by society at large.


Widget

No dog house here and my girlfriend likes them. For now, they are at my place, but when we retire, downsize and move in together, these will be keepers. It was either that, or a yet-to-be restored pair of Dynaco A25s (blasphemy!). These won. She likes the way they look and sound and they are big enough, without being too big for our future retirement residence.

[gdmoore28]

No dog house here and my girlfriend likes them. For now, they are at my place, but when we retire, downsize and move in together, these will be keepers. It was either that, or a yet-to-be restored pair of Dynaco A25s (blasphemy!). These won. She likes the way they look and sound and they are big enough, without being too big for our future retirement residence.


Your girlfriend has obviously fantastic taste. Now, if you will send me those "blasphemous" A25s I will make absolutely sure that she will never be forced to see them again. No charge. Address upon request. :)

GeeDeeEmm

[grumpy]

And aligning the script on the pots serves a useful purpose. It insures they are both in the neutral position when the knobs are set at the straight up 12 o'clock position.

If only that were guaranteed/true. It only insures that the L-pads are in their middle position when the knobs are straight up. 'Neutral', in a frequency response sense, may have required
the L-pads to be slightly canted for 12 o'clock to be 'flat'. In any case, I wouldn't worry about it too much unless there's a measurement system involved, as you'll want to adjust those
controls to taste anyway (or resolve to adjust your listening to accommodate the now-current 'flat' setting). Setting them accurately -equal- L to R (at least in a symmetrical listening arrangement)
can drastically improve the stereo effect... I'd personally fuss more over that than the absolute L-pad position.

Again, very nice restoration project! :)

[husq2100]

beautiful work! :thmbsup:

[Earl K]

Great Work there, MCM_Fan ! ( & beautiful, nicely framed, sharp photos ).

Can you also tell us about your camera ?

Thanks! :)

[MCM_Fan]

Great Work there, MCM_Fan ! ( & beautiful, nicely framed, sharp photos ).

Can you also tell us about your camera ?

Thanks! :)

Thanks.

The camera is nothing special. It's a Nikon D3100, which was their entry level DSLR when I bought it at Costco about 5 years ago. It came with two small zoom lenses and a camera bag. All the photos were taken with the standard 18-55mm kit lens.

[bedrock602]

Beautiful work! Truly inspiring.

[Rds]

Those look very good. Great attention to detail. I am the same way. Every detail counts on the finished product. Need to do this to my 36's.:D

[Rds]

I love the jbl l36. Had a pair in my late teens and enjoyed them before blowing them with a mean Nikko nr 1415 receiver. That was 80's. I bought a pair 5 yrs. ago and had the woofers prof. Reconed. Moved and just got em rocking. Only thing they sounded like they were missing lower mid range but still sounded great. Thought that was just the design. So I downloaded the manual for kicks and saw jbl's recommendation on setting the lpads. I had them all messed up. Manual suggests setting you amp/received tone controls to flat ie bass and treble 50%. Then set lpads to 12 o'clock and tweak from there. I only set the tweets to 75% afterwards. I tell you they sound ridiculous now. So much better with full frequency range represented. Guitars snare drums and vocals are way better now. I just did not know. If you are like me and haven't tried the jbl setting, I think its a good thing to try. Mine absolutely sing now. I can push more volume and produce a superior sound.:p

[BMWCCA]

Manual suggests setting you amp/received tone controls to flat ie bass and treble 50%. Then set lpads to 12 o'clock and tweak from there. I only set the tweets to 75% afterwards.

So this illuminating suggestion is essentially to leave your pre-amp/receiver settings at flat and do the same with the L-pads, and then adjust to your ears in your room?

What a revolutionary approach!

Begs the question "WTF were you doing before that?" :dont-know:

:banghead:

;)

[Rds]

So this illuminating suggestion is essentially to leave your pre-amp/receiver settings at flat and do the same with the L-pads, and then adjust to your ears in your room?

What a revolutionary approach!

Begs the question "WTF were you doing before that?" :dont-know:

:banghead:

;)

YOU

[Rds]

So this illuminating suggestion is essentially to leave your pre-amp/receiver settings at flat and do the same with the L-pads, and then adjust to your ears in your room?

What a revolutionary approach!

Begs the question "WTF were you doing before that?" :dont-know:

:banghead:

;)
I have a revolutionary question. Have you ever thought about not being stupid? Its a yes or no question.:applaud:

[BMWCCA]

I have a revolutionary question. Have you ever thought about not being stupid? Its a yes or no question.:applaud:

Saved for posterity. :lurk: