Replacing 2231 in 4333 with 2235

[Zilch]

Didn't Zilch say he was getting a pair of those made up ( sometime ago ) ?

What I have learned thus far is that three out of four E140's with "shifted" magnets actually have fractured magnets. The glue holds, and varying amounts of ferrite stays with it.

I've also learned that eBay sellers of E140 baskets that "need reconing" actually mean "virtually worthless - need rebuilding from scratch with new magnets" and get really, really bent when I call it misrepresentation and get my $$$ back from Paypal.

Notwithstanding the above, I'll have a pair of good ones back from the reconer tomorrow, looks like, if Dave wants to try them....

[Earl K]

Dave, substitute in some stock Zobel, stolen from a stock 2235H circuit ,

JBL uses those conjugates to trim the filters.

Right, thanks for the sobering second thought .

- Dave ( my best guess ), since this is an impedance equalizer / with an emphasis placed on impedance for the moment, retain the present 10 ohm resistor ( in the N333 ) and only replace the stock 20uF cap with a 14 to 16uF capacitor. The smaller capacitor will raise the effective turnover frequency of this equalizer. By keeping the 10 ohm resistor in place , the circuits working impedance in that upper area will be closer to what the network designer wanted / rather than if it was lowered to 7.5 ohms .
- This is still a crap shoot / but at least it's a cheap thrill for those who want to muck about .

[Earl K]

Whatever a Z . . . b . . . l is or does we now have three different ways of spelling it.

Okay,,, Zoobal ! ( happy now ? it's still easier to type than "impedance equalizer" )

[Earl K]

Hold on a second. Maybe I am a relative JBL newbie here BUT, wasn't the Zoebel there to curtail sub 100 Hz impedance issues? Is Zoebal relevant here?

- Relevance ??, Yes this Zobel is relevant for this application. This type of impedance equalizer is used to negate/flatten the typical rising motional (AC) impedance that usually occurs somewhere after 250 to 300 hz ( for JBLs' 15" woofers ).

- You may be getting this type of conjugate impedance equalizer confused with the conjugate LCR ( though these are typically used only on uppermid & tweeter type transducers .

[Earl K]

I'm just trying some 2235's in my 4333's. The bass is clearly tighter with lower distortion, but the midrange is just as clearly not as good.

A statement like that leads me to believe that you would really appreciate the extra articulation that the ME150H has in its midrange ( & everywhere else ). I assume the 1500Fe/1500AL also share this trait.

Once again, too bad I'm not local to your area / or else, I'd loan you my extra pair of ME150Hs for a spin in those boxes .

[4313B]

This type of impedance equalizer is used to negate/flatten the typical rising motional (AC) impedance that usually occurs somewhere after 250 to 300 hz ( for JBLs' 15" woofers ).

Here's a picture for those who like a visual. One can see this conjugate has a target of ~ 10 ohms.

[Chas]

- Relevance ??, Yes this Zobel is relevant for this application. This type of impedance equalizer is used to negate/flatten the typical rising motional (AC) impedance that usually occurs somewhere after 250 to 300 hz ( for JBLs' 15" woofers ).

- You may be getting this type of conjugate impedance equalizer confused with the conjugate LCR ( though these are typically used only on uppermid & tweeter type transducers .

Oh, okay I guess I had it backwards, frequency-wise, I should actually study the schematic before making stupid posts...!

Thanks for the graphics, Giskard. The zeebull makes quite a difference.