JBL L100T, Restoring and Upgrading!

[ramin_audio]

Hello Friends,

I have just brought home a pair of JBL L100T's. The speakers are generally in good condition. I want to restore them completely and upgrade the crossover. I need some help here.

1- The surrounds in the woofers are gone! Can I re-foam them myself?
(Where can I buy the kit for it?)

2- The cone in one of them is very slightly out of shape as you can see in this photo:



Is there a problem at all?

3- How can I get a new crossover for these?

4- The cabinets seem to be solid and it is heavy. Can a good bracing make any improvement?

5- The veneer is dirty. How can I clean it?

I really appreciate your replies to any of these questions.

Regards,
Ram

[hjames]

I have redone the surrounds on L100T speakers before - go to ebay and look up vendor LoonyTunes2001 -
http://stores.ebay.com/looneytune2001 - tell him what you need and he should be able to get you the right parts in short order.

A number of us have used his services and he makes a good kit to redo your Surrounds with.

The parts are fairly inexpensive so I'd take a shot at redoing the dead foams and not worry too much about the creased cone.

But - you are in Canada - its cold weather - and the glue used to redo foams does not do well when it freezes!
You may need to wait for warmer weather.

I highly recommend you search for Steve Vollmer's thread on restoring a pair of L100T with his son in Fall 2011 - lots of good stuff there!

[berf]

Don't worry about the crease in the cone, this actually is something that does not affect the sound. Just redo the surrounds and enjoy them for six months before you think about the crossovers. Learn about and work with positioning these in your room. If you have them against the wall or stuck in the corners it will affect the presentation far more than any crossover mods.

Go slow and be careful with the veneer. This was the beginning of the cheapening of the veneer on JBL's part. It's thinner than you wish it was and can be damaged through aggressive cleaning or sanding. There are many posts on cleaning, sanding, and re-oiling. Search the posts through Google and you'l find lots of excellent information.

[ramin_audio]

Thanks for the replies. I will refoam them first.

My JBL 4312A has the same tweeter and very similar midrange driver. The 2213H woofer is a fantastic woofer. I have given them to Frank Fabian (@ SpeakerShop) and he has made a new crossover for them and braced the cabinets... I believe, they are the best damn speaker in their own size (and frequency range) now -- very different than their original sound (which was boomy in bass with harsh mid and high!). Very tight bass now and the mids and highs are crystal clear and sublime! They are a perfect match for my Marantz 2330B.

I am planning to refoam these 2214H woofers of the L100T's myself, and after a while, will give them to Frank for upgrade and stuff.

Have fun.
Ramin

[ramin_audio]

I have two issues:

First:
I was reading this very helpful thread:

Resurround Step-by-step

One thing made me worry.

In post #16, it says: "The two completed baskets, hooked-up and running the 30Hz test tone for the entire drying cycle. This is what the drying phase looks like. It's a bit boring, but oh-so-important. Keep that 30Hz tone playing constantly - it ensures the voice-coil is centered, and allows you to hear if things need adjusting."

How am I be able to do that (i.e., ensure the voice-coil is centered)? Is there a special tool for this?

Second:
Beside the metallic frame, there are 4 pieces of foams, which have to be removed, as shown in the pic below:



I haven't seen these included in the refoam kits. Should I glue the old ones back after the refoam is done?

Thanks,
Ram

[hjames]

Yes, you peel off the cardboard gaskets first, clean them up and put them aside.
They get glued back on last, on top of the new foam surrounds, to help hold them in place.

I have two issues:

First:
I was reading this very helpful thread:

Resurround Step-by-step


One thing made me worry.

In post #16, it says: "The two completed baskets, hooked-up and running the 30Hz test tone for the entire drying cycle. This is what the drying phase looks like. It's a bit boring, but oh-so-important. Keep that 30Hz tone playing constantly - it ensures the voice-coil is centered, and allows you to hear if things need adjusting."

How am I be able to do that (i.e., ensure the voice-coil is centered)? Is there a special tool for this?

Second:
Beside the metallic frame, there are 4 pieces of foams, which have to be removed, as shown in the pic below:



I haven't seen these included in the refoam kits. Should I glue the old ones back after the refoam is done?

Thanks,
Ram

[svollmer]

I highly recommend you search for Steve Vollmer's thread on restoring a pair of L100T with his son in Fall 2011 - lots of good stuff there!

This will be a great project. Take your time and enjoy the process and you'll be very rewarded. Here's the thread Heather mentioned: http://www.audioheritage.org/vbullet...%27s+thanks+to

[svollmer]

I have two issues:

One thing made me worry.

In post #16, it says: "The two completed baskets, hooked-up and running the 30Hz test tone for the entire drying cycle. This is what the drying phase looks like. It's a bit boring, but oh-so-important. Keep that 30Hz tone playing constantly - it ensures the voice-coil is centered, and allows you to hear if things need adjusting."

How am I be able to do that (i.e., ensure the voice-coil is centered)? Is there a special tool for this?

Second:
Beside the metallic frame, there are 4 pieces of foams, which have to be removed, as shown in the pic below:



I haven't seen these included in the refoam kits. Should I glue the old ones back after the refoam is done?

Thanks,
Ram

Rick Cobb's kits come with a CD that has a 30Hz test tone that you can use. If you don't have that, an audio generator will also work if you have or can borrow one.

Regarding the foam pieces, take an Exacto knife and cut any adheasion between the foam and the side of the basket and between the foam and the top of the woofer surround and they'll come right off. You'll use the same glue that you use for the surround to replace them after the new surrounds are nice and cured.

[ramin_audio]

Yes, you peel off the cardboard gaskets first, clean them up and put them aside.
They get glued back on last, on top of the new foam surrounds, to help hold them in place.

Thanks for the info, Heather.

These woofers look to be in a good shape. They seem to be nice drivers... I will give them to a pro to re-surround them and totally service and upgrade the speakers.
JBL 4425 studio monitor has the same model woofer.

I am too busy these days, and when I come home I am frustrated! Messing up with these is the last thing I need.

The previous owner told me these speakers haven't been used for 15 years. Checking out the drivers, I believe he told me the truth.

[ramin_audio]

This will be a great project. Take your time and enjoy the process and you'll be very rewarded. Here's the thread Heather mentioned: http://www.audioheritage.org/vbullet...39;s+thanks+to

Hi Svollmer.

I read the whole thread. Not only was it informative, I really enjoyed reading. I bet you and your son have so much fun with these JBL's. Wish me luck.

[DavidF]

I have two issues:

"...
In post #16, it says: "The two completed baskets, hooked-up and running the 30Hz test tone for the entire drying cycle. This is what the drying phase looks like. It's a bit boring, but oh-so-important. Keep that 30Hz tone playing constantly - it ensures the voice-coil is centered, and allows you to hear if things need adjusting."

How am I be able to do that (i.e., ensure the voice-coil is centered)? Is there a special tool for this? ..."

Thanks,
Ram

The tone puts the coil into motion that is suspended magnetically in the gap. Assuming no damage to the coil or gap this acts as a means of self-centering for the coil.

[wu6fiend]

I will give them to a pro to re-surround them and totally service and upgrade the speakers.

Welcome to the wonderful world of L100T ownership. Aren't they terrific speakers? I own every model of the L-series (L20T, L60T, L80T and L100T) and am very fond of each of them. The L100Ts are one of my favorite possessions.

With regard to getting the surrounds redone, I'm not sure where you are located in Canada, but the staff at Vancouver Audio Speaker Clinic are very familiar with JBL product. Their work is top notch, and their prices are very fair. They've repaired a JBL center channel for me (internal wiring issue), and have refoamed a couple of pairs of JBL woofers too.

[ramin_audio]

Welcome to the wonderful world of L100T ownership. Aren't they terrific speakers? I own every model of the L-series (L20T, L60T, L80T and L100T) and am very fond of each of them. The L100Ts are one of my favorite possessions.

With regard to getting the surrounds redone, I'm not sure where you are located in Canada, but the staff at Vancouver Audio Speaker Clinic are very familiar with JBL product. Their work is top notch, and their prices are very fair. They've repaired a JBL center channel for me (internal wiring issue), and have refoamed a couple of pairs of JBL woofers too.

Hello wu6fiend,

Frank Fabian at Speakershop is authourized by JBL. He is very professional. He is the President and head of the Fabian Acoustics design team (Max Fidelity). I just gave him the L100T's this afternoon. He is going to make a new crossover for them with high quality components, and re-surround the woofers. Then, I am going to brace the cabinets myself, and sand and wax the veneer. I'll make a new risers and stands for them too... I think my JBL's will become super-L100T's.

Thanks
Ramin

[ramin_audio]

I have one question:

Do L100T and L100T3 have different cabinets? Are they different in size, or the material they are made of?

[Robh3606]

Do L100T and L100T3 have different cabinets? Are they different in size, or the material they are made of?

Yes the cabinets are different sizes and the crossovers are different as well.

Rob