After searching the forums a bit I found the following suggestions (sorry if I missed
some), and in no particular order other than the top two factory configurations:
1) Leave them the heck alone.
2) Use 5235 with 4430/4435 specific cards.
3) Bypass caps with high quality units.
4) Build up a clone network with presumably better parts, adjusting for inductor DC resistance.
5) Build up a charge-coupled network.
6) Build up a passive line-level network (high-pass specifically?) presumably in lieu of 5235.
7) Replace the 20uF protection cap with a higher quality unit.
8) Find a 2421 (aluminum) diaphragm (vs Ti).
9) Go apeshit and design your own active crossover using stock network voltage curves as a guide or as the law.
10) Add a negative impedance amplifier or EQ to the horn electrical path in an attempt to address 2-3dB of ripple on the low end.
So far, I can offer up experience with the first two (old/stock passive, and biamp using 5235+cards).
Both were capable of making me just sit and listen with disregard for the time.
Amps were JBL/UREI 6260's (one per side in biamp-mode).
No adjustments to L-pads were made (all set to 0). 5235 HF adj was set to 8.5 and flat bass (no bump or high pass).
Initial reaction to biamp was YUCK... then I flipped the polarity on the horn input on
both sides... now we're talkin. I guess I'm one of the few that like this configuration as
well or better than passive...May take extended listening to notice finer details.
With this post, I'm trolling for other's experiences with the care and
feeding of these very nice professional tools, uh, er, speakers. Right now, I'm content
to work on cosmetics and enjoy them for what they are, but thought it might be helpful
to get 4430/4435 work re-condensed in a new thread.
[ thanks to all for the specific responses that followed ...
no need for more schematics, almost everything mentioned is well within my capability,
I have most of the parts required, and can be evaluated in steps ... nice! ]