A little info on networks

[audioelmo]

I have installed a pair of the odd 2150 coax drivers into my newly acquired 1958 C-37's, they sound good to great, at least to my abused ears (36 years at a steel mill ),http://www.flickr.com/photos/57689236@N00/3302553946/ but they lack the highs above 6000 cps limited by those coax mids. I was wanting to add my set of slots tweeters, so I ask, can I use my pair of JBL N7000 crossovers, to divide the high side output of the 3125 crossover( cross at 1200 ) that the factory spec'd for the 2150's to feed the 077 slots?

What about a custom passive solution? Might someone suggest a drawing/parts list for such a home built 3 way network? I'm sure I could assemble it, US STEEL has me laid off right now, so I have more time than money, but I just don't have your knowledge to engineer/design it, or the sourcing for parts.
Any responses will be appreciated.

While here I just wanted to say, I have intently followed and enjoyed the threads of member "hjames" from her classic monitor purchase, their transport home, to the addition of the multi-amp rack solution, and how the members continue to help and advise, and her mettle to resist the condescending attitudes of some, and recognize that its really the music, the sounds, the result, not so much the buttons or the "stuff" as to why we enjoy what Jim and his older brother Altec started.:D

thank you all

Bob


My 2150 coax drivers

[Doc Mark]

Hey, Bob,

Just from my own experience with it, the 2405 sounds harsh, "spitty", and brittle, when crossed over at 7K. My very first 2405 came to me with a pair of 2130's, in a box, crossed over with a 3105, at 7K. Besides the huge hole in between the 2130 and the 2405, that slot tweeter sounded horrible to me, using that crossover!! I got the entire setup for $100, so I was glad to get it. But, after listening to it for a while, I incorrectly decided that the 2405's were horrible drivers. Imagine my surprise when I heard a pair of 077's (same basic driver) in a good setup, crossed above 8K! Sounded much better! I'd suggest crossing the 2405 no lower than 8K, and even better at 8.5K-10K. Makes a huge difference in the quality and smoothness of their performance, guaranteed!! Take care, and God Bless!

Every Good Wish,
Doc

[audioelmo]

Thank You for responding.

Would that harshness be the same with the bullet style ring unit?

What changes could be made to a n7000 to move that cross point?

On a connected issue, can these older/used networks benefit from fresh or modern type capacitors?

I have much to learn, and invite any who want to help,guide my early attempts to use available parts and my limited funds to get the best sound.

Thanks again.
Bob

[grumpy]

A contrarian view :):

Try the N7000. You might like it. If so, you're done.

...or look at MF/HF networks such as were used for the L65, as you
would be trying to match both a LE5-family driver response curve and
an 077/2405 curve and levels. If you like it, DIY the crossover and sell
the N7000's for cash.

I wouldn't bother modifying an N7000 unless it were already trashed.

-------------------
http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L65A%20Jubal%20ts.pdf

You'd need to leave out L4, and remove the high-pass bits of the MF section (C1) to use
with the 3125. Perhaps not optimum, but a fair start.

[audioelmo]

Hello Doc,
Nice of you to reply.
Terrific idea, this is why I'm here. The Jubal / L65 suggestion should be a close match.
Where does one find the individual parts at reasonable prices?
Yes, the N7000 are clean...and untouched. I'll keep for next project.

Thanks

[audioelmo]

In the past finding the inductors(coils),have been the hardest exact pieces to find. Where is the best place to buy single project quantities?
Bob

[grumpy]

Digikey, Parts Express, Newark, Solen, Madisound.... some are more DIY speaker
oriented, some more toward generic electrical parts. I'm sure there are hundreds of
others...

[grumpy]

Go crazy:

http://www.parts-express.com/speaker-building.cfm

but mind the "DCR" values if you're copying a JBL design.
Most are posted or buried here somewhere. If you get serious
about ordering parts, ask... someone will probably cough up
or measure a value for you.

[audioelmo]

Well,
There goes my afternoon...:)
I have plenty to look at now, start the wish lists.
Would it make sense to try JBL for factory replacements? They have some obsolete replacement parts.
Bob

[grumpy]

If you do, feel free to share your experience as another data point...
sometimes they pull through with bits I never would have guessed were
still available.

Might also try online auctions or listings for L65(a) or Jubal networks, as
these systems do get parted out from time to time. Could even be a member
here wants to sell one/some... I do not. Happy hunting.

[audioelmo]

I guess since the tent sale is down at JBL my goto guy has lost his job, or at least his company phone number. I left a message with the new guy, but no call back. Doubtful if that part is still on the shelf... I might try normal channels.
Bob