Evolution of JBL 2" driver

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I am starting this thread just to collect information about the evoultion of JBL 2" drivers, with as much detail as possible regarding the different models.

Any help collecting informations is appreciated. For example, the spec sheets I have found doesn´t say anything about any aquaplas diaphragms. Pictures of drivers, outside, inside, diaphragms, are welcome.

JBL 375: 1954. Aluminium diaphragm. Compression factor 8:1. Alnico V magnet. 20000 Gauss. 60 watts. Original horn H-5039. 100Hz-10kHz?
Links:
http://www.lansingheritage.org/html/...e-comp/375.htm
http://www.audioheritage.org/html/hi...beginnings.htm
http://www.audioheritage.org/html/pr...hartsfield.htm

JBL 376: 1979. Same as 375 except: Aluminium diaphragm with diamond suspension. 18000 Gauss? 500Hz-18kHz?
Links:
http://www.audioheritage.org/html/pr...bl/paragon.htm
http://www.audioheritage.org/vbullet...ot-info-wanted

JBL 2440. Same as 375, just different number? 500Hz-12kHz.
Links: http://www.jblpro.com/pub/obsolete/2440.pdf

JBL 2441. Same as 376, just different number? 500Hz-18kHz. 18000 Gauss.
Links: http://www.audioheritage.org/vbullet...BL-375-vs-2441
http://www.jblpro.com/pub/obsolete/2441.pdf

JBL 2445. Basically the same as 2440 except: Ferrite magnet, Titanium diaphragm. 100 Watts. 500-20kHz. 19000 Gauss.
Links: http://www.lansingheritage.org/html/...comp/2445h.htm

JBL 2446. Same as 2445, except: Coherent phase plug. Ribbed titanium diaphragm.
Links: http://www.lansingheritage.org/html/...-comp/2446.htm

JBL 2447. Same as 2446, except: 1,5" exit throat. Plain titanium diaphragm?
Links: http://www.lansingheritage.org/html/...-comp/2447.htm

JBL 2450. Same as 2446, except: Neodynium magnet.
Links: http://www.lansingheritage.org/html/...-comp/2450.htm

JBL 2451. Same as 2450. Really?
Links: http://www.lansingheritage.org/html/...-comp/2451.htm

Dates for different drivers is will find here: http://www.audioheritage.org/html/wh...te-history.htm, and update this post.

[Harvey Gerst]

Technically, the 375 (and all of its derivations) was a 4" driver with a 2" throat.

The 175, 275, and LE85 all used the same 2" diaphragm with a 1" throat.

100 to 10,000 Hz would be a very generous spec for the 375; it was more like about 300 Hz to a little over 9,000 Hz. On a short horn, 500 Hz was about the lower limit for a 375.

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A better title would have been "Evolution of the JBL 4" driver. Any moderators around?

2440 appears in the 1976 catalog: http://www.lansingheritage.org/html/...s/1976-pro.htm, as well as the 2482.

JBL 2482: 1976. Same frame as 2440 but incompatible diaphragm. Phenolic diapragm. 17000 Gauss. 300hz-6kHz. 120W.
Links: http://www.jblpro.com/pub/obsolete/2482.pdf

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2480: 1970. Phenolic diaphragm. 300hz-6kHz. 20500 Gauss. 120W.
Links: http://www.lansingheritage.org/html/...-comp/2480.htm

2485: 1986. Phenolic diaphragm. 300hz-6kHz. 19000 Gauss. 120W.
Links: http://www.jblpro.com/pub/obsolete/2485.pdf.

2490: 1998. 3" throat. Compression ratio 5:1. New phase plug. 250hz-4kHz. Titanium diaphragm. 200 W. 15000 Gauss.
Links: http://www.jblpro.com/pages/pub/components/2490.pdf

1955 catalog, http://www.lansingheritage.org/image...1955/page4.jpg, lists 375.

1969 catalog, http://www.lansingheritage.org/image...ome/page25.jpg, lists 375

1971 catalog, http://www.lansingheritage.org/image...1955/page4.jpg, lists 2440 and 2480.

1974 catalog, http://www.lansingheritage.org/image...pro/page14.jpg, lists 2440 and 2482.

1976 home catalog, http://www.lansingheritage.org/images/jbl/catalogs/1976-comp/page5.jpg, lists 375.

1978 catalog, http://www.lansingheritage.org/image...pro/page17.jpg, lists 2440 and 2482.

1979 home catalog, http://www.lansingheritage.org/image...omp/page05.jpg, lists 375.

1980 catalog, http://www.lansingheritage.org/image...pro/page19.jpg, lists 2441 and 2482.

1984 catalog, http://www.lansingheritage.org/image...pro/page21.jpg, lists 2441, 2445 and 2482.

1986 catalog, http://www.lansingheritage.org/image...986_pro/b4.jpg lists 2445 and 2485.

1998 catalog, http://www.lansingheritage.org/image...pro/page40.jpg,http://www.lansingheritage.org/image...pro/page41.jpg lists 2446, 2447, 2450, 2451, 2485 and 2490.

375 manufactured between 1954 and 1979.
2440 from 1971 to 1978.
2441 from 1980 to 1984.
2445 from 1984 to ?
2480 from 1971 to 1973?
2482 from 1974 to 1984?
2485 from 1986 to ?