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View Full Version : JBL L150a recap - suggestions on caps?



chad329
01-26-2012, 06:59 AM
I'm looking to do a recap, but wondering which brand caps to use? Right now they have stock Mylars. Anyone have experience and can give recommendations on different brands that would gel well? I know sound is subjective, but I'm just looking to build a short list to help nail down my selection.

The speakers have an in your face type sound that is consistent with all JBL's in the consumer line (my opinion anyway). I'm hoping to give them a concert hall or mid hall type sound. And I would like to take away the upper midrange harshness. Think liquid.

I've attached a pic of the stock cross over and schematic from JBL.

Thanks for the input everyone.

louped garouv
01-26-2012, 07:32 AM
lots of folks seem to like the Elna Silmic line...
I haven't used the personally, but have a DIY project coming up that specs their use...

here's a source -- no affil, etc...
http://www.hndme.com/productcart/pc/viewCategories.asp?idCategory=13

grumpy
01-26-2012, 11:13 AM
If you have unsuccessfully tried adjusting the L-pads to "tame" the frequency ranges,
I would humbly suggest that altering the capacitors to a different brand may not cure
the issue for you. One of the more significant such improvements could lie in 'charge-coupling'
the capacitors as opposed to simply replacing them, but again... if you're not fond of
the system as-voiced, subtle changes brought about by capacitor 'upgrades' may not
be a magic bullet.

I happen to like my L150a pair unmodified, so perhaps I shouldn't be the one giving
out such advice :)

rdgrimes
01-26-2012, 12:01 PM
Actually, the complaint of "in your face" might also be describing issues with early reflections or some other placement and/or room type issue. In any case, I'd expect that careful setup and placement will yield far more improvements than new caps will. Further, replacing the caps with any reasonable "same-kind" cap should yield more results than going to some "audiophile" cap that makes more of an impression on the wallet than the ears.

The L150A likes a big room and copious amounts of power. A too-small amp could also induce audible issues just as much as placement problems will.

grumpy
01-26-2012, 01:05 PM
The L150A likes a big room and copious amounts of power. A too-small amp could also induce audible issues just as much as placement problems will.

True dat. ;)

Going from a well-reviewed high-current 75w/ch bipolar-based amp to a ~300w/ch MOSFET unit really
opened these up for me, such that even non-critical ears commented on the difference.

rdgrimes
01-26-2012, 01:58 PM
When I moved up to Carver 350WPC amps for my stereo setup, the L96, L112 and L150 were all transformed into very different speakers. And the harder you push them the better they sound. If the amp is too small, the reverse will be true. These speakers are rated at 300WPC for a reason.

@chad329:
FWIW, the L96, L112 and L150A all use the exact same XO.

chad329
01-26-2012, 07:58 PM
Just to make things clear, I don't hate these speakers. I'm just interested in whether I can make them even better than they already are. I probably need a bigger amp, so far I've used a Sansui AU-717 (not enough power and showed), Sansui 9090db (decent at reasonable volumes), and an Adcom mosfet 5500, which is 200 watts in 8 ohms. The bass opened up when I added the Adcom to the equation.

I'm going to haul my speakers to friend's house and play them on a Bryston 4bsst and see what happens. There will probably be some magic in the air with that amp.

So is the consensus here to do nothing? I've had others suggest replacing the bypass with .01 Thetas for improved sound without altering too much. Of course, everyone says something difference which is why I'm just asking opinions here.

Thanks,

Chad

chad329
01-26-2012, 08:02 PM
Also, my room is big, about 4500 cubic feet. These speakers can play BIG and large space is absolutely needed or sound will be bouncing from everywhere. I agree with that completely. The first thing the guy said when he delivered my speakers (bought them from original owner locally) is how big my room was.

DavidF
01-26-2012, 09:07 PM
Just to make things clear, I don't hate these speakers. I'm just interested in whether I can make them even better than they already are. I probably need a bigger amp, so far I've used a Sansui AU-717 (not enough power and showed), Sansui 9090db (decent at reasonable volumes), and an Adcom mosfet 5500, which is 200 watts in 8 ohms. The bass opened up when I added the Adcom to the equation.

I'm going to haul my speakers to friend's house and play them on a Bryston 4bsst and see what happens. There will probably be some magic in the air with that amp.

So is the consensus here to do nothing? I've had others suggest replacing the bypass with .01 Thetas for improved sound without altering too much. Of course, everyone says something difference which is why I'm just asking opinions here.

Thanks,

Chad
What you want to achieve per your first post doesn't seem likely to be achieved simply by cap changes. In fact I am sure you won't. You will need to rework the xovers to get that change in response in the midrange. Not sure that's how far you might want to go with this idea. A place to start is the woofer roll-off and tweeter roll-on. Both are quite gradual and there is quite a bit of overlap in the midrange bandpass. Cut that overlap down and you might get a bit of sag in the midrange you need.