Build them for your rear channels, then.
And spin your chair around when you want to listen to jus' them!
[Gotta have more than ONE system to play, anyways....]
Build them for your rear channels, then.
And spin your chair around when you want to listen to jus' them!
[Gotta have more than ONE system to play, anyways....]
Hi Zilch
- Nice matched set of drivers .Along with Guido's PTH waveguides, a new pair of 2431H drivers came in. I mounted them in the modified L200's on PTF waveguides. No EQ, just the AM crossovers we're using, here's the performance, L & R:
- I'd like to see what they can do on a 650 hz horn with a low crossover point . Do you have any horns like that ?
- A quick suggestion ; I just spent about 10 minutes using the search engine to try to find ( within this thread ) the technical info that relates to your "AM" crossover reference . Maybe for the rest of us, you could note what post that info is found in so we can follow along . Thanks !
Hi, Earl.
"AM" crossover refers to HF section of AM6212/00, the JBL product which uses the 2431H on PTH (12" X 12" square) waveguides, but in combination with the LF section of 4430's N3134. Guido's building with 4435's N3135 LF.
I put together a parts list here:
http://audioheritage.org/vbulletin/s...age=21&p=48600
Note that R1 and L4 values are a little different in the HF section; we're using what actually came on the factory crossovers to start, which are not what's on the schematic:
http://www.jblproservice.com/pdf/AE%...6212,00-WH.pdf
JBL varies the HF crossover a bit depending upon which version of PT waveguide is used:
http://www.jblproservice.com/pdf/AE%...6212,64-WH.pdf
http://www.jblproservice.com/pdf/AE%...6212,95-WH.pdf
The simplest configuration seems to work with the PTF rectangular 100° X 100° waveguide as well, (see most recent RTA plots, above,) though we may be "finessing" them a bit with more experience.
I'm still using factory crossovers for both sections right now, waiting for parts to come in to complete my own DIY versions, in progress.
Ooops, there's the UPS guy right now.....
Like 2435H, I suspect they'd require the larger back cap to play worth a whit below 800 Hz.Originally Posted by Earl K
I could try them on the P-Audio 2344A clones, which are spec'd down to 500 Hz, but I don't have any true MF horns here for a REAL challenge....
Zilch
- Thanks for the AM update. I'll take a look at all that info this weekend .
- Now that you've established the HF capabilities of the 243x series / I would love to see just what it can do in the lower regions .
- One of the reasons I published those RTA pics of the B&C 900 / RCA horn was to demonstrate just how much lower midrange can be obtained when a large horn is used. By the way ; The cut sheet on that driver actually recommends a 1200 hz point ( at 12 db / octave ).
- Considering the 2431s' top end extension , I'd love to see what those 2431Hs are capable of on the H9800 . That would be a reasonable test / even with the tight back-cap . How about you and the Widget hooking up sometime in the future to suss this out ( or is the H9800 travelling ? ) Anyways
chow <>
1) DIY crossovers, nearly complete, await delivery of a few coils from Parts Express. N3134's (top) incorporate full original switching plus Zilch's new "Biwire" option using available 6th switch pole. AM version (bottom) for upgraded L200's is way simpler.
2) Switches for N3134 are prewired using 18 Ga. (16/30) hookup wire; 12 leads total required. They made construction a decidedly non-trivial endeavor. I had to break out the magnifying visor to build them, and it took over an hour apiece to do it. Wire colors denote six different switch functions, so the Zilchster gets the connections right.
3) Rear of N3134's prior to switch installation (bottom) and after (top). Bifurcated terminal ends (see unwired ones there) permit secure point-to-point wiring. Components are laid out to simplify it and minimize lead crossings, as if it were a printed circuit. 1/8" thick electrical-grade fiberglass substrate will mount on recessed rear panel per JBL convention. Boards are 7" square.
The input terminals used here are REdiculous. They'll accommodate lead wires the diameter of a pencil.
[Ordering up more of them for the AM boards, now.... ]
Nice work Zilch!
So you're not gonna bias the AM's?
The biased 4313 sounds so awesome that I gonna bias the 3135 and the AM's for sure.
BTW Horns are locked up in the custom. But no problem I'll get them out soon
Next project.Originally Posted by Guido
Thought we'd better get these "optimized" first.
Guido's gettin' his PT-H1010HF waveguides.Originally Posted by Guido
NOW this thread'll see some ACTION!
[Hopefully, he's got his 2431H drivers to go with 'em, too....]
Sonofagun's L200 grilles arrived today. Not glued to screens yet, they're just sittin' there lookin' like a million bucks! RTA finds them to be acoustically transparent.
While the texture is different, of course, the color is a close match to JBL Monitor Blue. Look closely at the closeup pic, and you'll see there's a swatch of factory grille cloth stuck on there for comparison.
Do we know the JBL Part# of those little plastic pinback logos? It'd be good to save forum members the embarassment of paying $25+ for them from the Orange County reconer guys....
Can ya hear 'em? That's Brian Ferry's "Frantic" they're playin'....
I have a pair of the original metal logos that are appropriate to the L100 and L200 among other JBLs of the era... If there were a number of members interested in them I could do a run of 20+ and they should be about $5 ea. maybe less.Originally Posted by Zilch
Widget
See pic in post #366. That's a 50 CFM Comair Rotron "Whisper XL" fan there, $27.40 at Digikey (#CR117-ND), plus $1.79 each for finger guards (2 required, #CR210-ND) and $1.80 for the 3' plug-on cord (#CR371-ND):
http://dkc3.digikey.com/PDF/T051/1372.pdf
Virtually silent in operation, it's just powerful enough to pull the solder fumes away without cooling the work. 70 and 83 CFM versions also listed there, same price, not so quiet, probably.
Ask at the target range if lead fumes are hazardous to your health. There's no sense breathing them directly....
I need to fill my wallet firstOriginally Posted by Zilch
Too many projects at the same time at the moment.
Buying a house (obviously the most cost effective )
Biasing 4313 clones
Building 2203 based Subs
Building the 4435 clones
I'll first test the Waveguides on 2426 and 2421 drivers in Ralf's 4430 clones.
You have NO sense of priority.Originally Posted by Guido
NOTHING matters but this....
We'll talk....Originally Posted by Mr. Widget
I've received several inquiries regarding my crossover construction method illustrated above. The push-in terminals I'm using were discontinued and the tooling destroyed 30 years ago. I only have enough stock for my own use presently.
BUT, I'm trying to round up more from surplus and grey-market sources right now. If there's enough interest, I'll consider making new tooling to produce them....
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