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View Full Version : L300/3133a Bi-amp question



pioneer
05-11-2007, 08:03 AM
An old subject but I have to ask.....I am in the process of having new crossovers made for me to bi-amp my L300's. We have the crossover points using the 3133a network at 800 and 8000 is that correct. The schematic makes reference to 500 at the low. Sorry if this a rehash of old posts but I could not find a clear answer.
thanks in advance
http://www.jblproservice.com/pdf/Network%20Schematics/3133A%20Network.pdf

Earl K
05-11-2007, 09:33 AM
In a word Project Everest is amazing.Today was press day at the suite which I was not aware of, but fortunately for me the Harman people took pity on me as the suite was on the far side of the Hilton way away from the main show floor and they allowed me to spend a truly unforgettable hour . I was given a seat dead center roughly 10 feet back and was treated to a wide variety of music that took the Project Everests to areas I have never visited in speakers before. I was fortunate that the press brought their own music (not that Mr. Timbers had a bad selection)and we went from vocals, Piano and violin, to Joni Mitchell (paved paradise) Grateful Dead (Uncle Johns Band ) The Who(Tommy) and many more which even brought all the Harman people to massive smiles most had not heard the Dead on the Everest yet. From the loud rock to the soft vocals the Everest are consistent. They have such a sweet high with the clearest and crispest bass I have ever heard and at all levels.
The cabinets workmanship is beautiful, unfortunately I did not have a camera but the pictures you have already seen will give you a good idea of the workmanship and they really do look better live.
Since I am at the show this is the best I can do on the fly as always the CES show is busy,but I will check in later if there is more I can add when I have some more time to think about it or hopefully others will chime in, but I can see others unable to be here wanted some info so I hope this helps a little.
In closing I left with a huge smile that stayed with me all day even though my feet are killing me(typical of this show).

- I took the liberty of reposting your listening impressions on the Everest II ( posted soon after you heard them at the 2007 CES show ) . The reason ( for the quote ) is a bit complex but in a nutshell I believe it may help you get additional responses to your query .


.....I am in the process of having new crossovers made for me to bi-amp my L300's. We have the crossover points using the 3133a network at 800 and 8000 is that correct. The schematic makes reference to 500 at the low.

- The L300a ( N333 ) schematic clearly states that the crossover points are 800 hz and 8500 hz.
- I don't know the source for your confusion and therefore the reason for your question ( still an assumption based on your exclusion of the usual question mark ) .

FWIW: The only place where 500 hz is almost mentioned in the schematic is where JBL states the "test range" of frequencies used when measuring the acoustic health of each individual driver/newtwork combo . Those test ranges are generically called "Sweep Frequency Hz" within the pdf file. The test frequencies 550 hz to 1200 hz are for the horn driver/network combo . A half competent tech ( not inferring you ) should be able to interpret this sort of techno-speak when it's included with a schematic.

- It does seem from the slant of your post that the person building your custom electronic crossovers isn't able to read JBLs' network schematics.
- If you feel that's a fair assessment then I'll also offer up, that you should be wary of paying for that persons' "design services" .
- Does this electronics contractor know how to run voltage drives ( for the N333 network ) / based on the extensive info given within the posted schematic ?


:)

pioneer
05-11-2007, 11:00 AM
Thanks Earl for the confirmation of the crossover points and I will assume that the crossover points are the same on the 3133a. I am sure being a very non-technical person with a background of only knowing what is pleasing to my ear that I asked the question the wrong way, my apologies.(That is always my fear of posting a question on this site). My tech is very knowledgeable knows how to read schematics and do the proper testing I do not and was asking the question just so that I know in my own mind that it is being built properly.

I am not sure why the quote from the Everest II thread was brought in, but if the reason was to remind me of how much I enjoyed hearing the Everest II in addition to having the pleasure to meet Greg Timbers and and John Eargle as well as the reviewers from Stereophile magazine, it has certainly brought back a fond memory. That listening session fed my desire to move forward on Bi-ampimg the L300's, especially after talking with Greg, he suggested that bi-amping would be a nice upgrade for them as I had explained to him that I felt the low end was lacking in my set-up.

Earl K
05-11-2007, 11:08 AM
My tech is very knowledgeable knows how to read schematics and do the proper testing I do not and was asking the question just so that I know in my own mind that it is being built properly.

- Okay ! Thanks for the clarification .
- I was afraid that you were asking these questions on behalf of your tech .


,,,, but if the reason was to remind me of how much I enjoyed hearing the Everest II in addition to having the pleasure to meet Greg Timbers and and John Eargle as well as the reviewers from Stereophile magazine, it has certainly brought back a fond memory.

- Yes, it's about the pleasure of listening to good things and wanting to capture that experience for all time .

:)

Zilch
05-11-2007, 11:09 AM
The relevance of E2 is charge-coupling.

If I were doing new crossovers to biamp 4333a, I'd be tracking down a charge-coupled equivalent (no tapped inductors) version network somewhere on this site....

hsmoller
05-11-2007, 06:18 PM
- It does seem from the slant of your post that the person building your custom electronic crossovers isn't able to read JBLs' network schematics.
- If you feel that's a fair assessment then I'll also offer up, that you should be wary of paying for that persons' "design services" .
- Does this electronics contractor know how to run voltage drives ( for the N333 network ) / based on the extensive info given within the posted schematic ?


:)[/quote]
After 20 years of being JBL trained and authorized servicer I think I should be able to read JBL schematics. Being here in the Philippines has not made me stupid just hot. The questions posed by my cousin are for his accumulation of knowledge on the subject which I have a great deal of respect for and so should you. I have spent a lot of time explaining the ins and outs.
Harv
who is now authorized servicer and installer for Johannus organs here
and restorer of the great Manila Cathedral 58 rank organ.