275nd / S3100 compatibility

[Earl K]

I am not so sure about outing the titanium diaphragm to replace it with the aquaplased one as I envision possible problems there. As Zilch noted above it might no be as easy as it sounds. Also, I would then end up with a modified 3100 rather than an 'official' MK II. I think I would rather wait untill I get another 275nd complete and then do the swap. I am however,very interested in what you have to say about using the MKii network with the 2426 though.

- I can understand that / though / you may want to try a fitup of your 275nd diaphragm into a 2426 assembly at some time / just to get a feel for its' "different" sonic texture. .
- I suspect that Zilch has encountered a "QC" issue that's mostly the result of the application ( by hand ? ) of the aquaplas coating. My 2, 2450SL diaphragms are different enough from each other that they really require different amounts of HF compensation from my passive hipasses .
- ie; ( & because of this experience ) I don't consider these JBL-shipped, aquaplas diaphragms to be a "plug & play" remedy to much of anything. Their QC is about the same as buying a carton of stock D8R2425 diaphragms .

If I read you correctly I could build the network now, use it with the 2426 and then on that great day when I pick up the second 275nd, I'm in business. Would the MKii network require much modifying to work with the 2426?

- Sure, I'd recommend that you get a mkII network when you can and use it with your stock 2426 drivers. The voltage drives that Zilch produced ( above ) do indicate this newtork also gives more HF content ( it's a bit more tweeter like ).
I know this advice is in contrast to something I've said previously ( I can't find that post right now ) / but whatever it was that I was thinking at the time / I was wrong . The mkIIs' LCR notchfilters lineup well enough with some undulations in my 2344/2426 workup that I can see that they are more driver/horn specific than diaphragm specific .

- Here's a .gif that represents a blast from the past ( when the 275nd was available as a part ).

[Bernard Wolf]

$605.00..... Ouch ! ... Guess the $200.00 or whatever it was I paid off of Ebay was a steal considering it looks to be 'brand new'. OK then, as soon as I can I will be off to Solen here in Montreal and see what they will charge me to build the networks. As my stock x'overs are external swapping them out will be a piece of cake. So, I guess what you are saying is that they will not require any mods to work with the 2426... very interesting.

If I manage to get everything up and running by the time you show up here in Montreal I would be more than happy to have you come and have a listen. Even if not, by all means drop by and hear the 3100 as is. Have you ever heard them? I'm very curious to hear what other JBLer's with experience have to say about the 3100. I have never really heard any other JBL other than mine and so have no real idea as to were they stack up in comparison.

Thanks - Bernard

[Earl K]

Hi Bernard,

Thanks for the invite !

$605.00..... Ouch ! ... Guess the $200.00 or whatever it was I paid off of Ebay was a steal considering it looks to be 'brand new'.

- Yeh, I posted that pic for reference.

OK then, as soon as I can I will be off to Solen here in Montreal and see what they will charge me to build the networks. As my stock x'overs are external swapping them out will be a piece of cake.

- I think we'll all be interested at what Solens' pricing will be .

So, I guess what you are saying is that they will not require any mods to work with the 2426... very interesting.

Sorry : Actually, that's not really the case ( though a new plug & play may be close enough for R & R ).

Still :
- The LCR notches will still need to be tweaked to properly zone in on the peaks produced by your specific 2426 drivers. Additionally, because the DCR values of the coils in the mkII are unknown, the notches are likely going to end up deeper ( from a custom Solen build ) than they ought to be ( unless you transport a speaker over to Solen so that they measure the results as they go along ).
- Also, my own preference would be to redesign the padding network to simplify it, to make it conform with what I perceive to be , more typical Northridge network design practices ( I'm a liitle uncertain if this network is GTs' handiwork or someone elses / it looks to be someone elses through my wandering eyes ).
- Also, this mkII network may benifit from having a LCR impedance correction network added to it ( as is found in the original N3100 ). This means someone needs to build the mkII network / measure it's overall impedance with drivers in place / then decide if the LCR impedance correction is applicable .

[Zilch]

There is the remote chance that one or more MKII networks are available off the shelf somewhere within the JBL consumer parts system.

Part numbers 333938-001 (HF) and -002 (LF).

I've had some luck in the past with this sort of pursuit. The hard part is getting someone knowledgeable of what's where on the phone....

From the depth of the notches shown in my simulation, knowing the DCR of the inductors is crucial to getting it right, and even then, they will likely have to be custom optimized for the different driver/diaphragm combinations.

Agreeing with Earl, it's unlikely Solen will be able to do it without samples, but I'd be interested in knowing what they estimate as the cost. Biased and bypassed, that network is at the high end of construction complexity in my experience....

[Zilch]

Indeed.

And other stuff, too....

[Earl K]

Orientation ; Zero Degrees to what ( horn edge & middle of slot ) ?

Also, what network is being used ?

[Zilch]

Hi, Earl.

0° is perpendicular to the horn face, and alignment is to the empirically determined (from impulse delay) acoustic center, which, best I can tell, is at the slot, NOT the driver voice coil or diaphragm.

Driver is offset 30° to the outside rear (left in the pic) by the throat.

Mic's at 30° in the pic, i.e., in line with the driver axis, orange curve, max SPL.

Filter is 18 dB/octave 1200 Hz FFBREQ in 5235.

Driver is BMS 4552nd-8.

Measuring distance is 44".

Unless I'm totally FUBAR here, the horn is amazing.

See CLIO Clinic for polar response measurement methodology:

http://audioheritage.org/vbulletin/s...442#post112442

Sitting at the apex of an equilateral triangle formed with a speaker pair, you'd be hearing the orange curve (30&#176, somewhat further back, the green (15&#176.

Then, as you move to one side, the nearer speaker goes toward the red (lower SPL) while the farther one goes toward orange (highest SPL), compensating for the change in distance and locking the image in place.

The effect remains operative even closer than the equilateral case due to the differential rates of SPL change with geometry.

[Bernard Wolf]

[
Sorry : Actually, that's not really the case ( though a new plug & play may be close enough for R & R ).

Still :
- The LCR notches will still need to be tweaked to properly zone in on the peaks produced by your specific 2426 drivers. Additionally, because the DCR values of the coils in the mkII are unknown, the notches are likely going to end up deeper ( from a custom Solen build ) than they ought to be ( unless you transport a speaker over to Solen so that they measure the results as they go along ).
- Also, my own preference would be to redesign the padding network to simplify it, to make it conform with what I perceive to be , more typical Northridge network design practices ( I'm a liitle uncertain if this network is GTs' handiwork or someone elses / it looks to be someone elses through my wandering eyes ).
- Also, this mkII network may benifit from having a LCR impedance correction network added to it ( as is found in the original N3100 ). This means someone needs to build the mkII network / measure it's overall impedance with drivers in place / then decide if the LCR impedance correction is applicable .

[/quote]

Very scary Earl... sorry to take so long getting back on this. Anyways, I have decided to leave well enough alone for the present as I am not really interested in experimenting right now. Besides which the 3100 sounds fabulous as is. I will just bide my time untill that second 275nd shows up. In the meantime, if you want to come over and take a listen while you are in Montreal that would be great. I have never heard any other JBL speakers and would be curious as to what your take on these would be.

PM me if you want to stop by and I will give you my coordinates.

Bernard

[Bernard Wolf]

Still :
- The LCR notches will still need to be tweaked to properly zone in on the peaks produced by your specific 2426 drivers. Additionally, because the DCR values of the coils in the mkII are unknown, the notches are likely going to end up deeper ( from a custom Solen build ) than they ought to be ( unless you transport a speaker over to Solen so that they measure the results as they go along ).
- Also, my own preference would be to redesign the padding network to simplify it, to make it conform with what I perceive to be , more typical Northridge network design practices ( I'm a liitle uncertain if this network is GTs' handiwork or someone elses / it looks to be someone elses through my wandering eyes ).
- Also, this mkII network may benifit from having a LCR impedance correction network added to it ( as is found in the original N3100 ). This means someone needs to build the mkII network / measure it's overall impedance with drivers in place / then decide if the LCR impedance correction is applicable .

Sorry to take so long responding to this post.. been rather busy...

The notion of doing all of the above is way beyond my needs/interests at this point in time... kind of scarry too ! Actually, I am more than thrilled with the 3100 as it is and so I will just sit tight and wait untill that day in the not too distant future - hopefully - when I do find that second 275.

In the meantime Earl, if you are in the area and would like to hear the 3100's please drop me a PM and we will work it out.

Thaanks - Bernard

[MatthiasA]

hello

i bought 2 H2600 for my two DIY S2600's
brand new from Harman Germany
but ive no idea where i can buy the adapter?
is there any part available in the USA?

Greetings Matthias

[Guido]

And they don't have the Adapter available?

[Jan Daugaard]

What does http://www.rw-soundsystem.de/ say who sold the H2600 horns to you?

[4313B]

- Here's a .gif that represents a blast from the past ( when the 275nd was available as a part ).

Yeah, I'm not real sure why they were discontinued. They were nice. I believe this one was the last one JBL had available and it went to France to another forum member. There are a few others at JBL, two in reference systems and one sitting on the shelf with all the other compression drivers they've ever made. I asked if I could shoot a picture of those shelves and the PWT. The answer was no.