Newbee w/ Modified 4311B's

[Zilch]

The woofers, if they are indeed 123A-3s, are wired correctly. The green with black stripe is (-), and the solid green is (+).

http://manuals.harman.com/JBL/HOM/Te...4311B%20ts.pdf

[KenMiles]

Wow- Homer had it all wrong but lucked out anyway!

The part I don't understand is, according to the schematic, if red is negative, why the woofer would push forward when battery positive connected to the cabinet red post- unless the 4311B meets the current standard at the cabinet posts. (???)

Oh, now I get it- the 4311B makes the correction in its wiring, add the mid is wired reverse from the woofer and tweeter too! (Schematic 3112B)

ThanX, Zilch

KenMiles

[boputnam]

I was curious how the older alnico magnet woofers would sound in them.

Again, alone, I remind of this quote in the OP.

If you do have the 123A-3 (and it "sounds" like you do, since now we learn these were sourced from some splendiferous L100's...) you are not getting that "AlNiCo sound".

:dont-know

[Zilch]

123A-3 is indeed Alnico, Bo. 2213 was the pro equivalent.

There were no ferrite L100s, I don't believe. :dont-know

[boputnam]

Yea, sorry... Ferhellsake - I should have known by the "A" designation.
Too many gigs this weekend to think straight about this stuff. I know better than to even begin to engage out here!

I was just plumb confused by the OP reference to the "D" prefix...

[Zilch]

The whole L100/4311 variant driver/crossover/polarity thing is so complex, there's no remembering it all. That means check the service manuals, find and re-read old threads, drag out a 123A-3 and put a battery to it, etc., etc., .

Screw it. I ain't answerin' no more inquiries about this. Fact is, it doesn't much matter what's in them or how it's connected, "It does not affect the sound."

Homer can handle it; he gets it right without any of that stuff....

[boputnam]

"It does not affect the sound."

:shock:

Now, Zilch, you know better...

[KenMiles]

Fact is, it doesn't much matter what's in them or how it's connected, "It does not affect the sound."

Hi Zilch.

Sorry this put you through so much. Homer is guessing polarity really mattered with the advent of subwoofers, but Homer's only guessing.

I've been listening to the modified 4311B's for about three weeks. I like the bass. Homer calls it 'tonal bass'- you can hear notes and texture.

Meanwhile, the musical chairs speaker rotation meant moving my Sony APM-22ES to another room to be matched with a Dynaco SCA-80. I wasn't certain of the Dynaco polarity, so I trialed both. Homer brought me a recording compiled using a signal processor. It has everything from low to high frequencies plus mixes of both. Curiously, there's a high frequency passage which is evident if played with the polarity hooked up one way, but is not evident when hooked up the other way!

I can send you a copy of this recording- is there a method of 'private messaging' on this site so that you can send Homer your address?

ThanX,

KenMiles

[boputnam]

Homer is guessing polarity really mattered with the advent of subwoofers, but Homer's only guessing.

Homer is right, but the guess is not restricted to "the advent of subwoofers". It matters a great deal, whenever more than one transducer is operating.

That said, most "consumers" might have first become aware of polarity with "the advent of subwoofers" as they encountered the "Polarity" switch on the rear of the sub cabinet.

You can send Zilch a "pm" - click on his moniker, and there you will see info about him and an option to "send a personal message". There are other ways, but this works...

[KenMiles]

Hi Zilch, Bo, JBL enthusiasts-

Zilch, Homer was eating a doughnut when he'd realized why the high frequency passage shows then disappears. Homer'd forgotten he'd swapped the CD player! One is able to register the high frequencies while the other doesn't.

Doh!

Homer says he can send a copy of the CD anyway.

ThanX,

KenMiles

[KenMiles]

Hi Zilch, Bo, JBL enthusiasts

I'd been auditioning my modified 4311B's for a little over three weeks now. When I cranked up the volume, it hurt my ears. I'd (foolishly) set the speakers were parallel to the walls. So Homer rotated my speakers about ten degrees inward- lo and behold, everything sounded way better at every volume level! Plus the bass really improved.




Uno,

[KenMiles]

to Zilch, Bo, JBL enthusiasts

Hi Zilch. Okay, here's part of the puzzle, a pic of the back of one of my 123A-3 woofers.


This view confirms the alnico magnet of the 123A-3



An enlarged view of the badge.


Apart from this, Homer and I are not at all satisfied with the midrange performance of the 4311B. Homer just last night reversed the polarity of the mids- he says now understands why JBL reversed the wiring of the mids. The speakers sound way harsh with the mids wired correctly. But I'd like to audition them myself for a while. Homer is also curious how the reputed smoother 104H-2 mids would sound with the altered wiring.

ThanX,

Homer,,, eh, KenMiles

[KenMiles]

Hi Zilch. Bo, JBL enthusiasts

Here's the latest modification, with 104H-2 replacing the LE5-10 midrange drivers. The speakers do sound less harsh with the 104H-2. Listening over time will tell.



The mods include 123A-3 woofers, 104H-2 midranges, with midrange wiring switched. Thanks to Zilch, Bo, and Homer for all their help.

KenMiles

[KenMiles]

Hi Zilch, Bo, JBL enthusiasts

I've been listening to my modified 4311B's for some weeks now. So far, I've found the most significant improvement by changing amplifiers.



This pic shows a Dynaco ST-120 power amplifier aquired in a trade for the original LE5-10's from the 4311B's. The Sansui AU-717 was split at the 'pre-out' switch, then the ST-120 connected to the AU-717 pre-amp.

This improved the sound and smoothed out the harshness I was suffering, particularly at higher volume levels. I was amazed at just how much the ST-120 improved the sound. My favorite listening right now is an old LP, Bernard Herrmann's movie music from 'The Three Worlds of Gulliver'.

I also experimented using a Dynaco SCA-80 to drive the modified 4311B's. In all, I'd estimate the choice of amplifier EXTREMELY important to getting the best sound out of JBL's L100 family of speakers.

Homer suggested a Dynaco PAS-3 pre-amp, so that's on its way.

ThanX,

KenMiles

[Rusnzha]

I set up my L100s with 123A-3s, 104H-2s, LE25-2s and charge coupled crossovers. It's amazing how good these things can sound if you put a some work into them.