2404 to 076 conversion

[Steve Gonzales]

I looked hi and low for a pair of 076 tweeters for my last (3rd) pair of L222/L220's to restore and found a wonderful compromise!. I had seen a 4612's in a car audio shop about a year back and asked the owner if he would sell them and he said he would think about it. Fast forward to the present. I could not get a handle on some 076's at all when I thought to check on the 4612's and see if I could at least buy them for the motors. After walking up and removing the grills (with permission) I was amazed to see that familiar little spun aluminum phase plug in the 2404H! He said, " I gotta have $200.00 for the pair"-DONE!!!!!!!!. I got them home and attached the pair of 076 lenses I had to the 2404H motors and WA-LA!! I then removed the original 076's from my L220's and popped the "Frankenstien" pair in to do an A-B test and am happy to report that they sound identical with the exception of being a bit more efficient. I sold the 4 2118J's to a friend for $200.00 so I got them for nothing. I just wanted to share this discovery with you all. I wish everyone Happy Holidays! ;)

[johnaec]

I believe the 4612's utilize the 2404H-1 HF, the difference being the the "-1" series uses the diapraghm from the 2402 instead of the 2405 diapraghm used in the regular 2404H. 'Couldn't tell you how different they'd sound, though, especially since I believe the original 076 used a special diapraghm to itself...


John

[Zilch]

Well, ain't THAT a kick!

Time to make up some 076/2403 lenses, perhaps. ;)

"Integrated Elliptical Radiator"

[I like 'em BOTH, tho....]

[Steve Gonzales]

Thanks John, you are right , they are H-1's and I can tell you that they sound IDENTICAL!!!, I am happy to report, The 076 did use it's very own specific diaphram and there are only about 10 left in the world from JBL as far as I know. I am so fortunate to find that this combination works perfectly and although the resale value is gone, the real world use is all I really wanted. Thank you for your input:)

Hey Zilch, is there someone who makes the lenses??????:confused:

BTW: As you see in my Avatar, my set up is perfect for doing an A-B test as the two pair are driven by identical amps.

[Zilch]

Hey Zilch, is there someone who makes the lenses??????:confused:Not that I know of, but 076/2403 being "dear" as they are, and rare, to boot, the interchangeability you cite brings forth the prospect of recreating them. It ain't as if there's very many lenses floating around out there. I'm surprised you had them, in fact.

2404's with busted horns are more common, for sure.

Not sure I understand the "H-1" deal, tho. Current data sheets spec 2402 at 2.5-15 kHz, 2404 at 3.0-21.5 kHz, and 2405 at 6.5-21.5 kHz. 2402 has 110 dB sensitivity, whereas both 2404 and 2405 are 105 dB....

[Robh3606]

Well that's good to know. I have seen the horns up on ebay a couple of times and wondered if you could convert them over. Thanks!


Rob:)

[johnaec]

Not sure I understand the "H-1" deal, tho. Current data sheets spec 2402 at 2.5-15 kHz, 2404 at 3.0-21.5 kHz, and 2405 at 6.5-21.5 kHz. 2402 has 110 dB sensitivity, whereas both 2404 and 2405 are 105 dB....Earl posted this back in January:

- I have 20 yr old ( Fall, 1983) JBL service info that supports a contention for a different diaphragm mass ( or maybe different coil - though not likely with the duplicated DCRs ) . It comes from a service bulletin ( # 231183 ) that describes the difference between the regular 2404 and the 2404H-1 ( as found in the 4612 ). The published statement is; the replacement of the regular D162405 diaphragm with a D8R075 ( giving a 2404H-1 ) enables a lower cross-over point that's 1000 hz lower than whats recommended for the typical 2404H .

Look for more info in this thread: http://audioheritage.org/vbulletin/showthread.php?s=&threadid=1462

John

[Steve Gonzales]

Yeah, I believe that the members have discussed this very subject AD NAUSEUM but thank you for the info. In my case, the drivers will be crossed over at 5K so minimum xover points are not a factor. What is great about this is that if you run into a set of lenses, you can fake it without the $800.00 + outlay and NEVER know the difference except on your BANK statement:cool:

[Steve Gonzales]

[QUOTE=Zilch]

Not sure I understand the "H-1" deal, tho. Current data sheets spec 2402 at 2.5-15 kHz, 2404 at 3.0-21.5 kHz, and 2405 at 6.5-21.5 kHz. 2402 has 110 dB sensitivity, whereas both 2404 and 2405 are 105 dB....

Must be DA HORNZ :D

[Zilch]

The 2404H's that several of us recently purchased on eBay include H-2's. That's printed on the back of one, Sharpied on the back of another, and two others had foilcals, now removed, i.e. unknown.

Anybody know what they are, then?

DCR: 6.8, 6.8, 5.9, 5.9

Curiously, the ones marked H-2 are 6.8 and 5.9, respectively. DUH!

6.8 is outta spec for either D8R075 or D16R2405 which is 5.7 ohms to 6.7 ohms....

[Earl K]

Maybe Not

In 1983,
healthy 2403(H), 2404H, or 2405(H) diaphragms, all had DCR ranges of 5.6 - 6.9 ohms

healthy 2402(H), 2404H-1 diaphragms, all had DCR ranges of 5.0 to 6.0 ohms ( 072 diaphragm )

So, my guess, is that the 2404s you just acquired, use an older 075 diaphragm ( before copper clad aluminum voice coils became the norm )

<. Earl K

ps - never heard of the 2404H-2,,, but that's beside the point .