Zonker92
All shiny and chrome
Over the past couple of years I've posted a lot of thoughts and threads on the JBL 4430 and 4435 large-format studio monitors. Since people sometimes PM me for advice or with questions, I thought I'd post up this cheat sheet summarizing many of my observations and mods. (Do not let this thread stop you from PMing me with questions or comments, but do please check this thread first, as it covers a lot of ground.)
Take all these ideas with a grain of salt; I'm just an amateur enthusiast. In some of the threads you will see people correcting some of my mistakes and erroneous assumptions.
Restoration/veneer/baffle paint/stain/finish/crossovers/damping material--see thread here: http://www.audiokarma.org/forums/showthread.php?t=654301
Finishes--see thread here: http://mail.audiokarma.net/forums/showthread.php?t=588281
Stands--see thread here: http://www.audiokarma.org/forums/showthread.php?t=561749
Baffle paint--see thread here: http://mail.audiokarma.net/forums/showthread.php?t=636991&page=6
Cabinet dimensions--see threads here: http://www.audioheritage.org/vbulletin/showthread.php?1075-Measurements-at-4430-Cabinet and http://www.audioheritage.org/vbulletin/showthread.php?2676-the-4430-DIY-thread and http://www.audioheritage.org/vbulletin/showthread.php?2355-4435-Diy
Damping--see thread here: http://www.audiokarma.org/forums/showthread.php?t=646389
Active crossovers--not really my area, but see thread here for at least some insights: http://www.audioheritage.org/vbulletin/showthread.php?6542-4430-X-Over
Ports--see thread here: http://www.audiokarma.org/forums/showthread.php?t=538592
Positioning--see thread here: http://www.audiokarma.org/forums/showthread.php?t=560092
Passive biamping--see thread here: http://www.audiokarma.org/forums/showthread.php?t=640456
Grills--see threads here: http://www.audiokarma.org/forums/showthread.php?t=672621 and here http://www.audioheritage.org/vbulletin/showthread.php?2520-4430-Diy
Internal wiring: Leave alone, I say. I think it's fine. You certainly can hard-solder all the wires to the PCBs. It would make for more stable long-term connections. I did not do it because it make it a lot harder to remove the PCBs for future work; I just cleaned up the connectors. I have tested my connections and the DCR is all basically zero, so I'm not too worried about it.
Rotary switch--see thread here: http://www.audiokarma.org/forums/showthread.php?t=537606 (more details and photos in the later pages of that thread).
L pads and rheostats: I would not bypass the L pads or rheostats, just because you lose some adjustment that way. If you do it, you will need to find your preferred position, measure the DCR on each of the two "pairs" of L-pad legs, and then replace each circuit with a separate resistor; see: http://www.audiokarma.org/forums/showthread.php?t=622331. Also, replace the rheostat with a resistor matching the DCR of the preferred setting. I'd use at least 12-watt resistors in each case.
Binding posts: I have used binding posts like these before (http://www.parts-express.com/dayton-audio-bpa-38sn-hd-binding-post-pair-satin-nickel--091-1247), but it is better with shorter threaded shafts, since the plastic back panels are thin. You might cut off the excess lengths of the shafts. And you will probably need to enlarge the holes for them. I wound up instead going with spring types like these, just because they're more OEM and they don't loosen with vibration: http://www.parts-express.com/spring-loaded-speaker-terminal-pair-nickel-13-16-tab--091-1142 (removed from their included panels).
Charge-coupled crossovers--see thread here: http://www.audiokarma.org/forums/showthread.php?t=636991. To delete the battery, see thread here: http://www.audiokarma.org/forums/showthread.php?t=532863
Coils and resistors--see thread here: http://www.audiokarma.org/forums/showthread.php?t=523597
Literature and specs--see here: http://www.audioheritage.org/html/profiles/jbl/4430-35.htm, and http://www.jblpro.com/pub/obsolete/443035.pdf and http://www.jblproservice.com/pdf/studio monitor series/4430lr.pdf
Compression driver diaphragms--see my review here: http://www.parts-express.com/radian-1225-8-diaphragm-fits-most-jbl-1-8-ohm--294-720
Recapping and bypass caps--see thread here: http://www.audioheritage.org/vbulletin/showthread.php?34407-Recapping-4430s I really can't recommend any particular caps, or using bypass caps, as I've not conducted any scientific listening tests. Personally, I use Audiocap Thetas for the smaller values and Jantzen Standards or Crosscaps for really large values, with Audiocap Theta bypass caps, but I make my choices based upon gut feelings, not science. Also, Zilch liked to use Dayton film caps with Audiocap Theta bypasses.
Eric
PS I think every thread should start with at least one photo, so:
Take all these ideas with a grain of salt; I'm just an amateur enthusiast. In some of the threads you will see people correcting some of my mistakes and erroneous assumptions.
Restoration/veneer/baffle paint/stain/finish/crossovers/damping material--see thread here: http://www.audiokarma.org/forums/showthread.php?t=654301
Finishes--see thread here: http://mail.audiokarma.net/forums/showthread.php?t=588281
Stands--see thread here: http://www.audiokarma.org/forums/showthread.php?t=561749
Baffle paint--see thread here: http://mail.audiokarma.net/forums/showthread.php?t=636991&page=6
Cabinet dimensions--see threads here: http://www.audioheritage.org/vbulletin/showthread.php?1075-Measurements-at-4430-Cabinet and http://www.audioheritage.org/vbulletin/showthread.php?2676-the-4430-DIY-thread and http://www.audioheritage.org/vbulletin/showthread.php?2355-4435-Diy
Damping--see thread here: http://www.audiokarma.org/forums/showthread.php?t=646389
Active crossovers--not really my area, but see thread here for at least some insights: http://www.audioheritage.org/vbulletin/showthread.php?6542-4430-X-Over
Ports--see thread here: http://www.audiokarma.org/forums/showthread.php?t=538592
Positioning--see thread here: http://www.audiokarma.org/forums/showthread.php?t=560092
Passive biamping--see thread here: http://www.audiokarma.org/forums/showthread.php?t=640456
Grills--see threads here: http://www.audiokarma.org/forums/showthread.php?t=672621 and here http://www.audioheritage.org/vbulletin/showthread.php?2520-4430-Diy
Internal wiring: Leave alone, I say. I think it's fine. You certainly can hard-solder all the wires to the PCBs. It would make for more stable long-term connections. I did not do it because it make it a lot harder to remove the PCBs for future work; I just cleaned up the connectors. I have tested my connections and the DCR is all basically zero, so I'm not too worried about it.
Rotary switch--see thread here: http://www.audiokarma.org/forums/showthread.php?t=537606 (more details and photos in the later pages of that thread).
L pads and rheostats: I would not bypass the L pads or rheostats, just because you lose some adjustment that way. If you do it, you will need to find your preferred position, measure the DCR on each of the two "pairs" of L-pad legs, and then replace each circuit with a separate resistor; see: http://www.audiokarma.org/forums/showthread.php?t=622331. Also, replace the rheostat with a resistor matching the DCR of the preferred setting. I'd use at least 12-watt resistors in each case.
Binding posts: I have used binding posts like these before (http://www.parts-express.com/dayton-audio-bpa-38sn-hd-binding-post-pair-satin-nickel--091-1247), but it is better with shorter threaded shafts, since the plastic back panels are thin. You might cut off the excess lengths of the shafts. And you will probably need to enlarge the holes for them. I wound up instead going with spring types like these, just because they're more OEM and they don't loosen with vibration: http://www.parts-express.com/spring-loaded-speaker-terminal-pair-nickel-13-16-tab--091-1142 (removed from their included panels).
Charge-coupled crossovers--see thread here: http://www.audiokarma.org/forums/showthread.php?t=636991. To delete the battery, see thread here: http://www.audiokarma.org/forums/showthread.php?t=532863
Coils and resistors--see thread here: http://www.audiokarma.org/forums/showthread.php?t=523597
Literature and specs--see here: http://www.audioheritage.org/html/profiles/jbl/4430-35.htm, and http://www.jblpro.com/pub/obsolete/443035.pdf and http://www.jblproservice.com/pdf/studio monitor series/4430lr.pdf
Compression driver diaphragms--see my review here: http://www.parts-express.com/radian-1225-8-diaphragm-fits-most-jbl-1-8-ohm--294-720
Recapping and bypass caps--see thread here: http://www.audioheritage.org/vbulletin/showthread.php?34407-Recapping-4430s I really can't recommend any particular caps, or using bypass caps, as I've not conducted any scientific listening tests. Personally, I use Audiocap Thetas for the smaller values and Jantzen Standards or Crosscaps for really large values, with Audiocap Theta bypass caps, but I make my choices based upon gut feelings, not science. Also, Zilch liked to use Dayton film caps with Audiocap Theta bypasses.
Eric
PS I think every thread should start with at least one photo, so:
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