4430 help!

[ricesinice]

I have been lurking around for a couple of weeks, and decided it was time to ask for some help. I have followed the 4430 quick and dirty thread but, it keeps going on tangents, and I have a couple of specific questions I would love to get answers for.

I have made a pair of 4430 type clones but, I used my own 12db/oct. 1khz crossover based on the dcr of the drivers, and a driverack to eq them. When playing at louder volumes, they seem to be a bit harsh. So, I am wondering if I should try to clone the 4430 crossover (is this a 18dB/oct. for the HP) to see if they play a bit smoother or just roll my own 3rd order and let the driverack do the rest? I would just bi-amp it but, that would require another amp which is not in the budget yet.

Thoughts to share?

Thanks

[Zilch]

Tangents? What tangents?

If you're using 2426H on 2344(A) horns, you need to clone the N3134 HP, at least, and the whole thing, HP & LP, if you're not biamping. Fortunately, that's easily accomplished.

There's more than just EQ in there. You won't get true 4430 character and performance without it, at least not so far as we have yet been able to achieve in the "Quick & Dirty" project.

I can only attribute it to "magic." Trust the Zilchster on this; it happens every time what I hook up using the factory crossover....

I can't tell you unequivocally it's better biamped, either. Having the passive crossover is essential to that appoach as well. Virtually all of those components remain in operation when biamping.

Your experience is well representative of that documented in the thread.

My guess is that the DR is pushing the 2426H too hard. Look at the published distortion curves of 4430, particularly how it's climbing exponentialy at the high end. Crank up the boost in that region, and it's gonna get outta hand mighty quick.

4430 operates at the limits of that 25-year-old technology, it seems. You have to stay within those limits for it to work. N3134 keeps you there and makes it happen in other ways, as well....

Nice lookin' stack you've put together there, BTW!

[Guido]

YEP!



Clone the 3134 and forget the driverack.

[4313B]

When playing at louder volumes, they seem to be a bit harsh.

I'm not sure just how loud you are playing them but the little 1" throat CD can be overdriven.

Ditto what Guido said. Bias them too if so inclined.

[ricesinice]

If I were to clone the n3134 are R210,202 available? Did I see somewhere the mid point values for these somewhere?
You are probably right about the Driverack, I used the speakers for a dance, and used it to eq the speakers flat...I was putting about 250 watts into each of these by the end of the night! The kids loved it but, I thought it sounded much better at about 3db less.

[Zilch]

R201 is a linear wirewound exposed porcelain rheostat. It's N/C past 30 Ohms (28, on one of two here). In other crossovers (e.g., 4425,) JBL used the P section of an L-Pad for this.


R202 is an 8-Ohm L-Pad. Center point is S=3.5, P=17.5. S=7 max., P=33 max. Non-standard?

4430 "0" is 3:00 on R101, range -6 (9:00) to +2 dB, 12:00 on R202, range -11 (7:30) to +4 dB.

You might be able to get the real things via JBL Pro Parts.

[Guido]

I was putting about 250 watts into each of these by the end of the night! The kids loved it but, I thought it sounded much better at about 3db less.

Sounds like a party

[Uncle Paul]

R202 & R201 are in the miscellaneous parts list (N15-61390-1 & 54840). The inductors are still listed as well. Not sure if they are actually available, though.

Does anybody know the part number for the 5 pole 2 position rotary switch or know of a suitable substitute?

[ricesinice]

Well, sent mail to JBL parts to see if they have the pots, if so, I will try to go ahead and clone the crossover. I bid on one at ebay a couple of weeks ago but, it got too high for me oh well

[Zilch]

While we say building N3134 is "easily accomplished," that's in theory. Nobody's ever put together a parts list with sources and costs here, that I'm aware of, even though several members have apparently made clones.

If the L-pad and pot aren't available from JBL parts, then standard parts could substitute, most likely. I don't think we care if the adjustment range comes out a bit different, and the "0" setting isn't at noon.

I looked at the costs at one time, and if I recall correctly, they came in a little over $100 for a pair, quite a bit less than the $565 each Pro Parts wants for them if they have them, which, when I last checked, they didn't....

[Robh3606]

The 3134's are no biggy to build. The replacement part JBL sells for the Rheostat is plain junk. Get the original or use a better potentiometer as a rheostat or run fixed values and switch them. Depending on how you want the back end of the curve to run you could drop in a fixed 4 ohm resistor as a start and just paralel up to drop the value. The inductor .04mh was available. I purchased a pair for my compensation units. That is the one inductor I would purchase from JBL to get the DCR right. Just get the pots from PE you should be fine.

Rob

[ricesinice]

Since I would probably order caps from Parts express I was wondering if you thought that PE lpad 260-255 would work for R202? And that sounds like a good idea just to use fixed value resistors for R201. Does anyone have the DCR's for the coils? I would like to roll my own, or reuse some of the ones I have sitting around in my basement....... can you say budget!

[Zilch]

Yes, that part will work. Again, buy two of them and use the parallel section of the second one as R201.

L102 is 0.6 Ohms according to Giskard in the "Q&D" thread, if I recall. See PE# 255-434. I'm startin' a parts list here.

Does anybody know the part number for the 5 pole 2 position rotary switch or know of a suitable substitute?

I did find a switch, Electroswich #C4D0604N-A, but it's $20. More research required, obviously.

http://www.electro-nc.com/rotaryus/c4.pdf

[ricesinice]

Boy, I think I am going to show my ignorance here! R202 wouldn't that require a stereo L pad?With the wiper connected and opposite ends of the resistor connected to ground? Also, I don't know what you mean to use a second one in parallel for R201. Shouldn't it be 30 ohm, or a couple of resistors totaling 30 ohm, and taking the feed off of the connection between the 2?
Simple minds want to know. This is one of the reasons I didn't try to tackle this sooner.. .but now with your exceedingly nice patience, and knowledge...

[Zilch]

I'm confusing you, apparently. You're gonna need four of those L-Pads, total, two in each crossover.

You'll wire one in each as R202 per the schematic.

Each L-Pad has two resistive elements in it. One, the "series" leg (because it's wired in series with the driver), between pins 3 and 2, varies between 0 and 8 Ohms as you rotate it CCW. The other, the "parallel" leg (because it's wired in parallel with the driver), between pins 2 and 1, concurrently varies between ~30 Ohms and 0.

So, to use the second L-Pad in each as R201, a rheostat, you'll just connect pins 2 and 1 only. Those PE units are 50 W L-Pads, and R201 is spec'd at 25 W. Should work just fine.

Look at 4425 crossover schematic. The same type L-Pad is used for both functions there.

The rotation is backwards, though; in 4425 it's wired as a shunt. Maximum HF attenuation will be at full clockwise in N3134. If so, we don't care....

Don't worry about the ignorance thing. I get smacked here all the time; it's the only way I learn.

My TRUE pals know to wait until the edit window is closed, so's it's here en perpetuity....