What would you do?

[Ralf]

I have still two old 075 alnico to lie here, which serve momentarily for my letters.
What would begin you thereby?
In former times JBL built these into two-way systems.

15kHz are not the top, but an attempt is it worth.

Greetings
Ralf

[Mr. Widget]

eBay

[Hofmannhp]

Originally posted by Ralf
I have still two old 075 alnico to lie here, which serve momentarily for my letters.
Ralf

Hi Ralf,

with ebay you can get max 160 Euros for a pair in working condition.
So ....here's my recommendation.......use it for your letters and be happy all days you can take a look to this parts.

Another idea is to buy some 077 or 2405 with cooked dias and use your dias for the 075. Otherwise you can use the horn and prism section of the 077 for the 075 and you got 20kHz.

HP

[Ralf]

Originally posted by Hofmannhp
Hi Ralf,

with ebay you can get max 160 Euros for a pair in working condition.
So ....here's my recommendation.......use it for your letters and be happy all days you can take a look to this parts.

Another idea is to buy some 077 or 2405 with cooked dias and use your dias for the 075. Otherwise you can use the horn and prism section of the 077 for the 075 and you got 20kHz.

HP

075 look nice but sound bad. For dividing they are too harm.

And Ebay? I have those already for 10 years. I cannot separate so simply from them.

ok. the letters are pleased about so mad parts...

[thevott]

I have a pair of 075s that I restored from burned-out and heavily-oxidized $10 thrift store artifacts into sparkling and sizzling showpieces with new JBL 16Ω diaphragms in grand hopes of someday building a Paragon around them . They do sound great as long as you stay within 1º of 'on-axis'! Anyway, I decided to experiment and found that when turned around backwards and reflected off a vintage Volkswagen/Porsche headlamp these tweeters actually achieve an acceptable horizontal and vertical dispersion pattern. When I get a chance I'll post of picture of this contraption which I showcased on my PA system once.

MP

[pangea]

Hi!

I'm a firm believer in "less is more". I have been experimenting a lot lately on how to make my gear sound as good as possible.

I have switched back and forth between 075 and 077's on top of my 2445J mounted on a pair of Selenium horns.

The setup that I find to be the absolute best combination thus far, is as follows.

My bass drivers 2231H and 2220A are bi-amped. (Soon there will be two 2123's taking care of the mid-bass from 250Hz to 1200Hz.)
My 2445J's are x-over'd at 1600Hz (6,5uF) first order, no lo-pass.
Then on top I chose the 075 for several reasons, one being similar in sensitivity, I have hi-passed them only using a 1 uF capacitor, 20 000Hz!!!
This somehow takes away the typical 075 hump and flattens out the response i.e. giving the 075 a "virtual" response up to 20k.
At the same time I still have the crispness and energy of the 075 which I LOVE so much. At 10k there is still 104 dB left!!! So it takes over from the 2445, when the response of the 2445 goes down a bit. It probably doesn't give a flat line response, but I don't think that's necessary on the other hand.

All together the music is so clean, detailed, accurate, unveiled and totally present, like NOTHING I have ever heard before or after. Each time I sit down and listen I'm completely blown away and flabbergasted by the soundstage. All my old records and CD's can now be played giving me a new experience and reveal nuances and details never heard before.

At one point I thought I would try to optimize the level on the 075's with a attenuation pot, but immediately had to disconnect it since the sound deteriorated severely, like a thick curtain was pulled in front of the speakers.
Finally I found a -3 dB fixed L-pad to be optimal for now.

Soon I will be able to measure everything properly, so maybe the values will change somewhat, although I doubt the changes will be significant.

I'm soooo pleased with the result already.

Has anyone done something similarly unorthodox?

BR
Roland

[pangea]

Originally posted by pangea
Hi!

Finally I found a -3 dB fixed L-pad to be optimal for now.

BR
Roland

The -3dB attenuation was put on the 2445's!!!

BR
Roland

[Alex Lancaster]

I have working, 2 pr of speakers with 3110 xovers (800Hz) to 2425J´s, 2312 horns and either 2402,4 or 5´s with just a 1 uF cap, the 2425´s are not cut off in the top end, and there is just no way the 2402´s will go as high as the others.

Alex.

[pangea]

Originally posted by Alex Lancaster
I have working, 2 pr of speakers with 3110 xovers (800Hz) to 2425J´s, 2312 horns and either 2402,4 or 5´s with just a 1 uF cap, the 2425´s are not cut off in the top end, and there is just no way the 2402´s will go as high as the others.

Alex.

Hi Alex!

I too have a pair of 2425J and these I have paired up with 077's, because I think they seem go together much better.
However I don't think the 2425J comes even close in comparison with the 2445J.
I don't know if it's the 2307 horn, or the 2425 itself that IMO sounds veiled and "cramped" in direct comparison, through A-B testing.

In my opinion the 075 complements the 2445 much better in every respect.

BR
Roland

[Speakertown]

Remember the 075 and 077's diaphragms have a
different alum. thickness. the 075's are thicker,
so you may not get the top end you want when
used with 077 assy.

[thevott]

When I replaced my 075/2402 bullet diaphrams they were the same part number as the 2405 slot and the 2404 butt-cheek.

MP

[Speakertown]

JBL may have come up with a compromise
one-fits-all replacement, they used to have
different pt. numbers. This was discussed here
last year, it was understood that they used
a certain mil thickness to match the horn
response. Of course, with aftermarket replacements, who knows what you'll get.

[thevott]

I'll try to dig up the JBL boxes and/or literature to verify my statement. I replaced the diaphrams in the mid '90s. Let's hope they defaulted to the lighter weight material. I haven't measured the response but they sure sound like they go all the way up.

MP

[thevott]

...All the way up if you are directly ion axis and don't budge one inch in either direction!

MP

[pangea]

Originally posted by thevott
...All the way up if you are directly ion axis and don't budge one inch in either direction!

MP

Hi MP!

Is that a proven fact, or is it something you just would like to think?

My 075's don't seem to be that stingy.
I have a fairly decent "sweetspot" and sure enough it's sufficient for me.

BR
Roland