375 vs 2440 What is the Difference

[mbottz]

Can any one out there tell me the differences between the 2440 and the 375. Is there a sound difference? Thanks for any info you can give.

[Mr. Widget]

They are functionally identical. They use the exact same diaphragm, throat, phase plug, magnet and cast return pot.

The differences are color, nameplate, terminals, and depending on the vintage, possibly the back cap shape.

In the voodoo that is audio, I am sure there are those that will tell you that one sounds better than the other. The 375 and all of the consumer versions of JBLs are more collectable and therefore more expensive on the used market than their pro counterparts. If you compare a 375 and a 2440 and they do sound different, which isn't that unlikely, it is because one or both are not operating up to spec. Intact "Red Wax Seals" is certainly no guarantee of condition.

Widget

[LE15-Thumper]

Intact "Red Wax Seals" is certainly no guarantee of condition.

Widget

I hear ya Widget. My LE85's would cut out on certain bass notes from the LE15's. Turned out the short 3" wiring inside the driver itself was loose under the screw terminals.
What can you do ? Had to pop those red cherries to fix 'em.

[Roddyama]

The chances that the used 2440's seen more rigorous service than the used 375 is probably pretty good.

[Steve Schell]

You have to be careful when buying these drivers used. As Rodd pointed out, many of these drivers have been used and abused for many years in professional systems. Some have been installed in outdoor systems and suffer from rusting of the internal parts. It is a bad sign if the external paint finish is coming loose and falling off.

One fellow I know has made quite a study of 375, 2440 and 2441 drivers. He often demagnetizes and disassembles them, blasts off the old paint, removes rust, remachines the mating surfaces if necessary, repaints, reassembles and remagnetizes them. He supplies them to another friend who builds complete systems. They were noticing large variations in response curves between drivers of different vintages, and began to notice differences in construction. Ultimately they identified seven distinct versions of the drivers; changes over time in the pole pieces, phasing plug geometries, etc. They found that it is necessary to pair up drivers with similar features in order to get stable imaging from a stereo pair.

The ones to look for should have close serial numbers and a nice external appearance. Chances are they have been used in a hi fi rather than a prosound application.

[Lancer]

Great information guys!

Thanks

[scott fitlin]

You have to be careful when buying these drivers used. As Rodd pointed out, many of these drivers have been used and abused for many years in professional systems. Some have been installed in outdoor systems and suffer from rusting of the internal parts. It is a bad sign if the external paint finish is coming loose and falling off.

One fellow I know has made quite a study of 375, 2440 and 2441 drivers. He often demagnetizes and disassembles them, blasts off the old paint, removes rust, remachines the mating surfaces if necessary, repaints, reassembles and remagnetizes them. He supplies them to another friend who builds complete systems. They were noticing large variations in response curves between drivers of different vintages, and began to notice differences in construction. Ultimately they identified seven distinct versions of the drivers; changes over time in the pole pieces, phasing plug geometries, etc. They found that it is necessary to pair up drivers with similar features in order to get stable imaging from a stereo pair.

The ones to look for should have close serial numbers and a nice external appearance. Chances are they have been used in a hi fi rather than a prosound application.

I have six 2441 drivers purchased new in 1979-80, I have two 2440 drivers I got with a pair of lenses, dated 1972! I have always said they sound different than the 2441 from 79, even with 2441J diaphragms! Everyone said they ( the driver itself ) is the same, except for the diaphragm! The older drivers have a slightly different gap width! THEY DO SOUND DIFFERENT! I never measured the differences, but to my ears, the older drivers with 2441 phragms sound sweeter, to me anyway!

Thank you Steve!