View Full Version : JBL L150A Upgrades...Help !!!

02-09-2004, 12:50 PM

I own a pair of 150A's which I love, I reconed and refoamed them up to factory specs.

I've been reading in audiogon.com that re wirering the internal wires with newer, better quality wire (Cardas, Audioquest, etc.) will definetely improve sound quality.
I would also like to upgrade capacitors and resistors in the crossover.

1-Any experience with these kind of upgrades ?
2-Where can I find schematics and specs to do the job ?

Thanks in advance,


02-09-2004, 02:17 PM
Try this!

02-10-2004, 08:52 AM
Thanks Guido for the x-over schematics.

Any info on someone that has done the same thing ?



02-10-2004, 08:58 AM
Further to my reply above.

Which brand do you suggest for capacitors and resistances...Vishay ?, I would get the same on the same values that are shown on the schematic, just thought that in 22 years since manufactured, my speakers could use some surgery.

Also....what kind of solder to use ?


02-10-2004, 10:11 AM
I'm curious - I have a pair of L150, (not the "A" series), and wondered if the crossover is the same in both versions?


02-10-2004, 10:17 AM

I really don't have a clue if the crossovers are the same....I even don't know the difference between the 150's and the 150A's.



02-10-2004, 10:27 AM
As far as I know, the L150 and L150A are the same with the exception of the HF unit.

02-10-2004, 10:45 AM
Different networks too. This is all documented on this forum. There is a search button available in the upper right corner.

02-11-2004, 09:08 AM
Originally posted by Foxtrot
....I even don't know the difference between the 150's and the 150A's.


02-11-2004, 09:21 AM
bo - thanks for those specs! Interesting.


02-12-2004, 10:45 AM
Ref:" Thanks Guido for the x-over schematics.
Any info on someone that has done the same thing ? Rod"

I upgraded my L150's by replacing the mids with a 104h and adding the bypass capacitors. I used the Dayton .01 polypropylene caps (part # 027-450) from Parts Express.
The bypass caps made the most improvement in clarity/smoothness in the sound. I was shocked at how much better they sounded with the bypass cap. addition. I have thought about replacing the 033 HF with 035Ti, but I believe the network has to be replaced. Using the 4412 network was suggested, but I have not found a used one to buy yet.
Terry M.

02-12-2004, 09:58 PM
Actually, if you've already got a 104H in there for mids, and you want to use an 035Ti for a tweeter, I'd suggest the 120Ti crossover... it's virtually the same drivers- 128H/H1 woofer (same drivers, just different placement of the aquaplas on the front vs. the rear of the cone), 104H and 044Ti (which, IIRC, differs from the 035Ti as having a metal flange as opposed to a plastic one on the 035ti).

You might have to re-tune the crossover a bit for the difference in low-end response (the 120Ti has a higher bass rolloff point, which might change the subjective balance a bit to the ear), but I'm guessing, it would be minor... probably a slight change in tweeter output level and upper end shelving. If anything, I'd guess a little more top end would be in order, to "counter-balance" the increased relative bottom end...


02-13-2004, 09:09 PM
Hi Rod
Did you get the e-mail regarding the L150a mods that I have done?


02-14-2004, 12:18 AM
Hi Steve,

I did receive your email, I've been quite busy at work so I've had no time to focus on the x-over mod/upgrade.

If you don't mind I'll br conactimg you soon with some questions.