My new 4430 system

[grumpy]

foil-cal removal (should you need to):
I've used a ~3"-wide spackle knife + heat gun (or blow drier and patience)
to cleanly remove the thick (foil-cal-wise) L-pad cover without marring the cabinet.

http://www.jblproservice.com/pdf/Stu...ies/4430LR.pdf

used an oven mitt the second time...

Interesting DIY project source (e.g., parametric EQ):
http://sound.westhost.com

[3dbdown]

Thanks Grumpy,

Hoping I won't have to do that, but now I know how.....

Interestingly, when I pulled the knob off the L-pad, things settled down a bit. I noticed the L-pad shaft was a bit cocked in the baffle cutout, and am now wondering if stress on the shaft may have been highlighting the problem. Not familiar with the mechanical construction of the pot, whether or not contact position could be affected so I'll still try De-Oxit. Wanted to get to that step today, but events took over and was not able to.

I can't imagine JBL finished goods QC missing that, so maybe it's been tampered with subsequently. Anyway, thanks to your advice, I'll prevail one way or the other.

Question now is, if I have to replace the L-pad, are they still available? If not, I will need another source/advice for a replacement.

Although I don't hear anything that I would not attribute to a dirty pot, I really hope the diaphragm is OK. Hope those replacements are available, and I would not consider other than JBL......maybe edgewound knows, and I am fairly close to him....by California mileage standards anyway!!!

I suspect they are fine, however, based on their sound, so I won't go looking for trouble!!

Rick

[oznob]

It's a great feeling when you finally get your system dialed in, congrats Rick! I am a big fan of two ways done right. I put the 4430 at the top of the heap even above the S3100, Altec Model 19, Valencia etc. based only on my experience with these speakers. I would be curious to know if you feel your speakers would benefit from the addition of, for lack of a better term, a super tweeter crossed pretty high, say 12K to 15K? May be a difficult question to answer but I never felt the need for it with the 4430 or the 3100. There are some on the forum who would disagree. Maybe their hearing or "trained ears" are better than mine? I would be very interested in your thoughts.

Mark

[3dbdown]

Mark............

Thanks for the Kudos, and it truly is a good feeling........

As to your question, I don't really know yet....In the process of playing with EQ, I did do a little tweaking in that range, and my first impression is, that the 2425h handled it pretty well......At least, I think I have 2425H's....I haven't pulled them apart yet.

The JBL documentation says 2426H, but I don't yet know the exact vintage of my cabs. I asked on the serial number thread, but have not gotten a response yet.

This may not be the place to ask, but my serial #'s are 256386 and 256391.

I was a big fan of the 2405's in my Jubals, and it's hard for me to think that they might not add something positive, but then, I have to get more used to the 4430's before I could make a really informed comment on that.

I plan to stay off the EQ as much as possible.....I don't want to wind up using it as tone control.

Besides the possible phase shift issues, a wise old transducer engineer once told me that when you start adding or subtracting too many bands of EQ....It's called volume control!!!

So, I'm only planning it for the room node problem, and using the available tone controls on the Marantz for problems with any program I might be listening to at any given time.

I just know that I really like these babys, and know that no matter what I do in the future, I will not be getting off my 4430's!!

Rick

[3dbdown]

Mark....

Forgot this.....I'm also a big two-way fan.....Always was at JBL, and still am.

I would trade 3 pairs of Decade 36's for one pair of Decade 26's any day of the week, and twice on Sunday!!

I had a pair on my desk at JBL, and remember many nights at 8, 9, or 10 o'clock.....working on the drawings to get the L212 out on time....That those '26's kept me going !! Wish to God I still had 'em today !!

Rick

[BMWCCA]

I'm also a big two-way fan.....Always was at JBL, and still am.

I would trade 3 pairs of Decade 36's for one pair of Decade 26's any day of the week, and twice on Sunday!!

I had a pair on my desk at JBL, and remember many nights at 8, 9, or 10 o'clock.....working on the drawings to get the L212 out on time....That those '26's kept me going !! Wish to God I still had 'em today !!

That's encouraging! I just bought a pair for $29. They're sitting in a friend's office in SC waiting for me to pass by or find someone going my way from there. I look forward to hearing them.

-Phil
030, L112, L150A, L20T, 4412A, L5 . . . and L26

[3dbdown]

Don't let 'em get away, Phil !!

Rick

[oznob]

Thanks for your comments Rick. I have had my share of 3 and 4 ways, including 250ti's but, I always come back to the big horn loaded two ways. I guess I feel that less is more. I have never owned or listened to the venerable 43XX studios which may change my mind but hey, they are out of my price range at this time anyway. All of my current speakers, save for the garage sale L100's, are two ways. My favorite is the 4301B with Zilch's updated crossovers. I can listen to them for hours! The 3100's are keepers and I am confident in their new surroundings they will shine. Of course an Array 1500 sub would sure help!
Mark

[BMWCCA]

Don't let 'em get away, Phil !!

No problem. I bought them off Ebay as "local pick-up only" and had a friend pick them up for me. He's checked them out and said they're fine. I'm not scheduled to be in that office until early next year but someone will be headed this way and want to feed my JBL jones before then. Got an $18 Soundcraftsmen DC-2215 EQ the same way a couple of months ago and it's home now.

I figure Heather will probably go antiquing in SC and deliver them to my door!

[3dbdown]

Hi, forum!

Well, I'm getting the period correct systems together, and loving my 4430's. I'm going to pull the networks next week, and replace the caps with something better, Solens, and get rid of the four .01uf bypass caps in the process. I'm told, by reliable authority, that this simple, inexpensive fix will really open the monitors up, including the woofer circuit.

I would like to maybe go the charge-coupled route, but can't locate a schematic/parts list by which to do it......Maybe someone knows???

My most immediate agenda is, however, to locate a receiver with tuner, with pre-amp outs, just two-channel analog, to run the 4430's with. I just want some INEXPENSIVE, but current technology to fire them up.

And so, here is my question: What do you guys think of the Harman Kardon 3385?? They can be picked up for a song on E-bay, refurbished by HK Factory Folks, and can even be gotten new for about $210.

This would certainly not be the end all be all for the 4430 system, but it would be more period correct, as well as free up my Marantz 2325 for restoration, later to be plugged into my Jubals and 4311's for the "Intermediate mid-'70's" system.

My "Old technology" system is the restored Fisher 400 tube receiver, with turntable, plugged into the JBL Alpha 1's....used exclusively for my old vinyls.

So, I'm open to suggestion on the newer technology receiver, and I don't need the power amp section, as I'm quite happy with my QSC's.

Any help or thoughts on the Charge-Coupled route for the N3134's as well as the HK 3385, or alternate choices would be most welcome....

Thanks,

Rick

[4313B]

Any help or thoughts on the Charge-Coupled route for the N3134's as well as the HK 3385, or alternate choices would be most welcome....

I think I posted the cc 4430 network schematic several years ago. I think you might want to go cc with that receiver. I ran 4430's for a time with unbiased Solen's, both non-bypassed and bypassed, and ended up going biased.

***

Yep, I have the cc 3134 network schematic on my HDD but will have to reload AutoCAD to snap a photo of it for posting.

***

First one is full passive, second one is bi-amp only.

Here is a link to a copy of the original schematic at JBL Pro - 3134

[3dbdown]

Thanks so much 4313B......

When you referenced "that receiver", with respect to CC being the better approach, did you mean the HK-3385 or the Marantz 2325?

I notice in the second schematic, the HF is still paralleled to the LF input. You say that's the Bi-amped version, so I would think the input to the HF should be across the 40uf cap and pin 1 of the L-pad. What am I not seeing? Keep in mind, I'm totally unfamiliar with the CC approach!

Also, you talked about "biased". Was that the CC network, or the original passive networks? Although I understand biasing, I am not sure I understand what you mean in this particular context. I wonder if you were talking about using or not using the .01uf bypass caps in the original non-CC networks?

Rick

[4313B]

When you referenced "that receiver", with respect to CC being the better approach, did you mean the HK-3385 or the Marantz 2325?

HK 3385 or HK 3485

I notice in the second schematic, the HF is still paralleled to the LF input. You say that's the Bi-amped version, so I would think the input to the HF should be across the 40uf cap and pin 1 of the L-pad. What am I not seeing?

Sorry, I never finished the drawing. So here it is finished. It looks nicer before I cut and paste it into Paint Shop Pro and then post it. If I had a MAC it would probably all work perfectly.

Also, you talked about "biased". Was that the CC network, or the original passive networks? Although I understand biasing, I am not sure I understand what you mean in this particular context. I wonder if you were talking about using or not using the .01uf bypass caps in the original non-CC networks?

I tried the networks with Solen capacitors and didn't like the results.
I bypassed the Solen capacitors with the JBL 0.01 uF bypass capacitors and didn't like the results.
I biased the Solen capacitors and liked the results.
"biased" = "cc" = "charge coupled"

Note that the 20 uF of series HF capacitance in the bi-amp only version is part of a 2-pole filter. The second pole is in the 4430/4435 card for the JBL 5234A and 5235 electronic frequency dividing network. Some people argue that using either JBL network negates the benefits of bi-amping and they are probably right because they do sound pretty bad these days. I think a few guys have sufficiently modified them to sound better. One could use a line level high pass instead of an op-amp high pass if one knew the input impedance of the HF amplifier. One might also want to see if they can do without the zobel/conjugate (and 9 V biasing source) across the 2235H in the bi-amp only version.

[Chas]

Member 4313B has already said it, but I have to reiterate it based on my own experience. If you are going to the trouble of pulling the network boards, etc. non-CC Solens will not be optimal.
Good luck.

[mech986]

I tried the networks with Solen capacitors and didn't like the results.
I bypassed the Solen capacitors with the JBL 0.01 uF bypass capacitors and didn't like the results.
I biased the Solen capacitors and liked the results.
"biased" = "cc" = "charge coupled"

Note that the 20 uF of series HF capacitance in the bi-amp only version is part of a 2-pole filter. The second pole is in the 4430/4435 card for the JBL 5234A and 5235 electronic frequency dividing network. Some people argue that using either JBL network negates the benefits of bi-amping and they are probably right because they do sound pretty bad these days. I think a few guys have sufficiently modified them to sound better. One could use a line level high pass instead of an op-amp high pass if one knew the input impedance of the HF amplifier. One might also want to see if they can do without the zobel/conjugate (and 9 V biasing source) across the 2235H in the bi-amp only version.

Hi 4313B,

Although I have looked and searched, I don't recall seeing any thread on modding the 5234-5235. Can you suggest anything to bring them to decent standards (5234 uses the first basic opamps u741's ) or are we really better off just getting a more modern design (M53x units or other brands?) to do the biamp/active crossover work?

Bart