Hello! It's a privilege to make part of this group. My JBL history is, my father married my mother in 1977, and he took her for Honeymoon where? In California, just to see the JBL factory (she didn't knew that),
and he make some shop, now in 2010 he made an upgrade and changed his system to Wilson Audio Alexandrias and Holland amplifiers, and i'm lucky because i'm earned all his system, that i've always loved.
Since i've put my hand on it, i've saw a loooot of problems, and want to make some modifications, i would love to have some opinions on it. The system is:
2 2405 16 OHMS
2 JUBAL (077 TWEETERS + MEDIUM + 12"WOOFER 126A)
4 15" 16 OHMS WOOFERS (2 are passives, no wires)
2 HORNS 2440
2 LENSES 2310
LUXMAN VALVE CROSSOVER 2003
2 CROWN DC300A MONO - WOOFERS
1 CROWN D150A - HORNS
1 CROWN D60A - TWEETERS
1 CROWN D300A - JUBAL
My main problem is with the tweeters. When i've opened the Jubals, was one 077 tweeter and one 2405, and on the main system, one 077 and one 2405. i don't know why, and my father neither.
i've opened it and for my surprise, the kit on jubal was with blue diaphragm and cristal lenses, so i've figure that someone has made changes and don't know why someone has putted one blue diaphragm
on 2405 and the crystal lenses... I've taked to a repair center to see the impedance of the golden diaphragm and the blue diaphragm, the golden date of 1997 and the blue 1977, and supriselly
both are 8 ohms! I've saw someone here saying that is normal 2405 ship with 8 ohms diaphragm, i think is crazy, because it says 16 ohms, how you buy a tweeter and is different that shows.
He putted the blue diaphragm on the 077 and the golden on 2405, and i've opened now and saw that the polarity is inverted.
Sooo. Here are my questions:
1- De black dot on the Diaphagm is the negative or the positive?
2- the 4 diaphragms are in great condition, worth buy 2 - 16 ohms diaphragms for the 2405? will result in better sound, or something better? (i have separate amplifiers so i can adjust the gain)
or i can use this 8 ohms and it's the same of the 16 ohms in sound quality?
3- If i use this 8 ohms diaphragms in all of them (077 and 2405) with one is better? the blue dated 1977 or the gold dated 1997?
4- I simply LOVE the cristal point, my father said that the 2405 is newer and professional, so it has some difference in why they changed to metal, i don't know about that, so here i am
like a child asking, can i use the crystal point on the 2405? (that's because i'm guessing that the 2405 is better to use like my main tweeters, i don't know) or the metal is better? If i hit the
plastic part with my nail it sounds like TAC TAC, if i do the same on the metal part it does TINNNN TINNNN, i don't know if it's metal just because it's stronger and its the pro series, or it
make difference in the sound...
5- How can i figure it out that the golden diaphragm is from JBl and not aftermarket? The blue is different one from another, as the pictures show.
Here are some pictures, thank for your time and patience to make a very happy guy!